Papers by Chanthini KANAGARAJ
Efficacy of Precocene I from Desmosstachya bipinnata as an Effective Bioactive Molecules against the Spodoptera litura Fab. and Its Impact on Eisenia fetida Savigny, 2021
The sustainability of agroecosystems are maintained with agro-chemicals. However, after
more than... more The sustainability of agroecosystems are maintained with agro-chemicals. However, after
more than 80 years of intensive use, many pests and pathogens have developed resistance to the
currently used chemistries. Thus, we explored the isolation and bioactivity of a chemical compound,
Precocene I, isolated from the perennial grass, Desmosstachya bipinnata (L.) Stapf. Fractions produced
from chloroform extractions showed suppressive activity on larvae of Spodoptera litura (Lepidoptera:
Noctuidae), the Oriental armyworm. Column chromatography analyses identified Precocene I
confirmed using FTIR, HPLC and NMR techniques. The bioactivity of the plant-extracted Dp-
Precocene I was compared to a commercially produced Precocene I standard. The percentage of
mortality observed in insects fed on plant tissue treated with 60 ppm Db-Precocene I was 97, 87 and
81, respectively, for the second, third and fourth instar larvae. The LC50 value of third instars was
23.2 ppm. The percentages of survival, pupation, fecundity and egg hatch were altered at sub-lethal
concentrations of Db-Precocene I (2, 4, 6 and 8 ppm, sprays on castor leaves). The observed effects
were negatively correlated with concentration, with a decrease in effects as concentrations increased.
Distinct changes in feeding activity and damage to gut tissues were observed upon histological
examination of S. litura larvae after the ingestion of Db-Precocene I treatments. Comparative analyses
of mortality on a non-target organism, the earthworm, Eisenia fetida, at equal concentrations of
Precocene I and two chemical pesticides (cypermethrin and monocrotophos) produced mortality
only with the chemical pesticide treatments.
Systemic defense induced by fatty acid compounds from marine macroalgae, Chaetomorpha antennina in tomato (Solanum lycopersicum) plants alters the susceptibility of the polyphagous agricultural pest, Spodoptera litura Fab, 2024
Background Seaweeds contain a widespread range of fatty acids (FA), and several of them have pote... more Background Seaweeds contain a widespread range of fatty acids (FA), and several of them have potential
bioactivity. FAs are dynamic members of all biota, as well as being acknowledged for their critical function
in initiating phytohormone interactions and acting as important participants in many defense signalling pathways
of the plant system. The current study looks at the defense-eliciting potentials of fatty acids from the green seaweed
Chaetomorpha antennina (Bory) Kützing and their impact on the polyphagous insect pest Spodoptera litura (Fab).
Results The seaweed was detected with 19 fatty acids, with larger proportion of hexa and octadecanoic and linoleic
acids. The algal fatty acid compounds (CFA) were successful in eliciting salicylic acid and phenolic compounds
biosynthesis along with defense enzymes peroxidase (PO) and polyphenol oxidase (PPO). CFA enhanced the synthesis
of defense enzymes, PO and PPO and phenols, post infestation with S. litura (> 50%) compared to control plants
exposed to the pest. CFA was also effective in causing direct mortalities (96–98%) to the larvae (II-V instars). S.
litura larvae exposed to elicited tomato plants displayed physiological incursions that extended larval-pupal
duration to 26–28 days, preventing both morphogenetic transitions as well as affecting their morphology, that lead
to the emergence of adults with malformed wings, legs. As a consequence, the fecundity was reduced by 60%
affecting the reproductive performances of second-generation adults. The consumption rate (RCR) of larvae
exposed to CFA was decreased by 84%, depicting feeding deterrence. These larvae were also observed with > 50%
reduction in the levels of phosphatase enzyme secretion, bringing down larval growth rate from 0.58 to 0.34 mg/day.
Histological analysis of exposed larvae displayed midgut cell disruption.
Conclusion Hence, the study finally confirms the elicitor potentials of fatty acid compounds from C.
antennina, by inducing natural systemic defenses. This investigation unlocks novel forecasts besides delivering
an unconventional method for crop protection to moderate or interchange the solicitation of chemical pesticides.
Inhibition of pathogen and induction of resistance against early blight: Alternaria solani Sorauer in tomato plants (Solanum lycopersicum L.) through external application of compounds from seaweed Chaetomorpha antennina Bory, 2023
Background The indiscriminate application of pesticides has depleted soil fertility. Marine algae... more Background The indiscriminate application of pesticides has depleted soil fertility. Marine algae are regarded
as excellent sources of bioactive compounds that can stimulate plant growth and also enhance their resistance
against biotic and abiotic stressors. Compounds derived from the marine algae Chaetomorpha antennina (Cladophoraceae)
were analysed for their biocontrol efficiency against the tomato disease pathogen Alternaria solani
as an alternate technique to preserve agricultural output sustainability.
Results The active fraction from the methanol extract of C. antennina (CA-F8) proved effective against the pathogen
in vitro by affecting A. solani’s spore germination (92.13%) along with their mycelial growth thereby decreasing their
dry weight (44.71%). GC–MS examination revealed the presence of fatty acids (defence pathway activators), terpenes
(antimicrobial compound) and antioxidants (deactivators of pathogen enzymes). Seaweed compounds also elicited
polyphenol oxidase (PPO) (78.8%) and peroxidase (PO) (54.6%) synthesis, along with stimulating the accumulation
of foliar phenols (67.5%) that are components of jasmonic acid defense pathway, higher compared to control plants.
Salicylic acid was detected only in treated plants, thereby offering efficient disease control.
Conclusions By triggering natural systemic defences, salicylate (SA) and jasmonate (JA) mediated pathways;
the study demonstrates the elicitor potentials of chemicals from C. antennina that was efficient in controlling early
blight (EB) disease. In addition to providing a different method for crop protection to reduce or replace the demand
for chemical pesticides, this study reveals unique projections
Biological activity of chitosan inducing resistance efficiency of rice (Oryza sativa L.) after treatment with fungal based chitosan, 2021
Reduced pathogen resistance and management of the left-over rice stubble are among the most
impor... more Reduced pathogen resistance and management of the left-over rice stubble are among the most
important challenges faced in rice cultivation. A novel and eco-friendly strategy to synthesise ‘Fungal
Chitosan’ (FC) from Aspergillus niger using rice straw could serve as a sustainable treatment approach
to improve both disease resistance and yields, while also effectively managing the rice stubble waste.
The FC treatment promoted germination as well as growth parameters in rice varieties, TN1 (high
yielding-susceptible) and PTB33 (low yielding-resistant) better than a commercial chitosan (PC).
Treatments of exogenously applied FC to plants produced direct toxicity to Xoo, and reduced the
BLB disease index by 39.9% in TN1. The capability of FC to trigger a cascade of defense pathways
was evident from the measurable changes in the kinetics of defense enzymes, peroxidase (POD)
and polyphenol oxidase (PPO). FC treatment increased levels of POD in TN1 by 59.4%, which was
35.3% greater than that of untreated PTB33. Therefore, the study demonstrated the effectiveness
of FC treatments for use in agriculture as a potential biostimulant as well as protective agent against
bacterial leaf blight, BLB, of rice (Oryza sativa) that could be produced from stubble waste and
improve rice stubble management strategies.
Chaetomorpha antennina (Bory) Kützing derived seaweed liquid fertilizers as prospective bio-stimulant for Lycopersicon esculentum (Mill), 2019
Plant nutrition serve as critical factors that influences plant growth and yield. Global fertiliz... more Plant nutrition serve as critical factors that influences plant growth and yield. Global fertilizer production and
application is growing in surplus amounts, increasing the agricultural expenses and damaging the environment.
Organic fertilizers, obtained from natural sources, encompass all essential plant nutrients. Application of aqueous
seaweed extracts are regarded as potential plant biostimulant agents. The liquid seaweed extract of green
seaweed Chaetomorpha antennina (CA-LSE) were evaluated for their biostimulant activity on seed germination
and growth of tomato. The CA-LSEs were able to stimulate early emergence of tomato seeds, in addition to
increasing their germination percentage and energy. They also exerted a positive influence on the vegetative
growth, resulting in increased plant height, leaf-branch number and yield. The CA-LSEs were influence the
plant's biochemical profile and displayed a linear increase in pigment contents (chlorophyll a & b and carotenoids),
total soluble solids (TSS), phenols as well as ascorbic acid contents. The bio-stimulant potential was
attributed to the elements present in CA-LSEs, elucidated by EDX analysis that revealed the presence of six
elements (O, Na, Mg, S, Cl and Ca), that were essentially plant nutrients. These results support the bio-stimulant
potential of C. antennina, which can be applied as a prospective bio-fertilizer that is economic, renewable,
efficient and eco-friendly, and also can be regarded as a potential catalyst for the betterment of sustainable
agricultural food production.
Sustainable Agronomic Strategies for Enhancing the Yield and Nutritional Quality ofWild Tomato, Solanum Lycopersicum (l) Var Cerasiforme Mill, 2019
Urbanization and global climate change have constrained plant development and yield.
Utilization ... more Urbanization and global climate change have constrained plant development and yield.
Utilization of wild gene pool, together with the application of sustainable and eco-friendly agronomic
crop improvement strategies, is being focused on to tackle mounting food insecurity issues. In this
aspect, the green seaweed, Ulva flexuosa, was assessed for plant biostimulant potential on cherry
tomato, in terms of seed priming e ects, nutrition and yield. SEM-EDX analysis of U. flexuosa
presented the occurrence of cell wall elements (O, Na, Mg, S, Cl, K and Ca). The phytochemical
analyses of liquid seaweed extract (EF-LSE) revealed the presence of carbohydrates, protein, phenols,
flavonoids, saponins, tannins and coumarins. The EF-LSEs were found to stimulate seed germination
in a dose-dependent manner, recording higher seed germination, and biomass and growth parameters.
The seedlings of treated seeds altered the biochemical profile of the fruit, in terms of TSS (93%),
phenol (92%), lycopene (12%) and ascorbic acid (86.8%). The EF-LSEs positively influenced fruit
yield (97%). Henceforth, this investigation brings to light the plant biostimulant potential of the
under-utilized seaweed source, U. flexuosa, to be useful as a bio fertilizer in agronomic fields for a
cumulative enhancement of crop vigour as well as yields to meet the growing food demands.
Biologically active toxin from macroalgae Chaetomorpha antennina Bory, against the lepidopteran Spodoptera litura Fab. and evaluation of toxicity to earthworm, Eudrilus eugeniae Kinb, 2021
Background: Seaweeds harbour a wide array of bioactive compounds shown to be effective in support... more Background: Seaweeds harbour a wide array of bioactive compounds shown to be effective in support of sustainable
agricultural practices. The green seaweed Chaetomorpha antennina found in abundance in coastal areas of India
has been reported with various bioactivities. Owing to the requirement of alternative and economical natural pest
control method to be applied in sustainable agronomic strategies, the current study attempts to evaluate the efficacy
of chemical toxins from C. antennina, as insecticidal agents, by inspecting their effects on the physiology, biochemistry,
immune system, and histology of one of the most important insect pests of agricultural crops in the Asian tropics,
the polyphagous lepidopteran Spodoptera litura.
Results: The active fraction 5 isolated from C. antennina using methanol extraction produced significant mortality
rates of S. litura among all the other fractions obtained. GC–MS analysis revealed the presence of various pesticide
compounds. The toxin compounds (active fraction 5) were found to negatively influence the pest’s immune system
performance at sub-lethal concentrations (
LC50 38.73and LC90
53.60 ppm), affecting insect development, reducing
the haemocyte count (69.24%) and reduced the activity of major defence enzyme phenoloxidase decreased posttreatments.
Digestive phosphatase enzymes, acid phosphatase, ACP, alkaline phosphatase, ALP, and ATPase were
demodulated by 37.5, 39, and 23.9% compared with untreated. Increase in detoxification enzymes coupled with midgut
collapse are indicative of the toxicity of the compounds. Earthworms exposed to seaweed compounds displayed
no debarring effects.
Conclusion: Extracted seaweed compounds produced significant lethal effect on the insect larvae, affecting the
immune as well as digestive systems of the pest. However, no such toxicity was observed in earthworms treated with
the seaweed fraction supporting their environmentally benign nature. Since the insect immune system is responsible for the development of resurgence against pesticides, suppression of immunological activities by seaweed toxins
indicate the long-term applicability of these compounds as prospective pesticides. The results support the potential
of chemicals from C. antennina for biopesticide development to manage economically important agricultural pests.
The Macroalgal Biostimulant Improves the Functional Quality of Tomato Fruits Produced from Plants Grown under Salt Stress, 2022
Among the most perilous factors affecting tomato plant functioning and yield is salinity.
The eff... more Among the most perilous factors affecting tomato plant functioning and yield is salinity.
The efficacy of halotolerant marine macroalgal extract of Chaetomorpha antennina (Seaweed Extract—
SWE) in mitigating the toxic effects of salt stress (150 mM) in tomato plants to promote and enhance
both plant functionality and yield was tested. It was evident that salt stress undesirably affected
germination and plant growth in terms of quality and quantity. Treatment with SWE improved the
functionality of salt-strained tomato plants by enhancing their germination indexes, growth and
morphological traits, and photosynthetic pigments, as well as protein and phenol concentrations. SWE
also exerted a positive influence on protecting the plant against salt stress by increasing the synthesis
and accumulation of antioxidant enzymes, superoxide dismutase and lipoxygenase enzymes, along
with the contents of lycopene and vitamin C. SWE also increased the nutraceutical quality, flavour and
organolepty of emerged tomato fruits. GCMS analysis of fruit pericarp showed increased siloxane,
phenol, antioxidant and indole acetic acid compounds, along with aromatic benzene compounds.
These results indicate the potentiality of SWE in protecting plants against salt stress induced toxicities
by prompting the synthesis of protective compounds such as siloxane and antioxidant enzymes.
It was also noted that SWE plays a crucial role in promoting plant growth and survivability by
improving plant functionality, yield and nutrition, by promoting cultivation in saline soils in an
eco-friendly and sustainable manner.
Aqueous Seaweed Extract Alleviates Salinity-Induced Toxicities in Rice Plants (Oryza sativa L.) by Modulating Their Physiology and Biochemistry, 2022
Around the world, salinity a critical limiting factor in agricultural productivity. Plant
growth ... more Around the world, salinity a critical limiting factor in agricultural productivity. Plant
growth is affected by salt stress at all stages of development. The contemporary investigation focused
on Chaetomorpha antennina aqueous extracts (SWEs) to decrease the effects of salt strain on rice germination,
growth, yield, and the production of key biological and biochemical characters of the rice,
Oryza sativa L. (Poaceae). SWE improved the germination capacities of rice seedlings by promoting
their emergence 36.27 h prior to those that had been exposed to saline stress. The creation of 79.647%
longer radicles by SWE treatment on salt-stressed seeds which boosted the establishment effectiveness
of seeds produced under salt stress longer radicles resulted in plants that were 64.8% taller. SWE
treatment was effective in revoking the levels of protein (26.9%), phenol (35.54%), and SOD (41.3%)
enzyme levels that were previously constrained by salinity stress. Additionally, SWE were also
efficient in retaining 82.6% of leaf water content and enhancing the production of photosynthetic
pigments affected by salt exposure earlier. The improvement in plant functionality was evident from
the display of increase in tiller numbers/hill (62.36%), grain yield (58.278%), and weight (56.502%).
The outcome of our research shows that SWEs protected the plants from the debarring effects of salinity
by enhancing the plant functionality and yield by mechanistically enriching their physiological
(germination and vegetative growth) and biochemical attributes (leaf RWC, photosynthetic pigments,
protein, phenol, and SOD). Despite the increase in TSS and starch levels in rice grain exposed to
salinity stress, SWE improved the grain protein content thus cumulatively enhancing rice nutrition
and marketability. The current investigation reveals that the extracts of C. antennina can help alleviate
rice plants from salt stress in an efficient, eco-friendly, as well as economical way.
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Papers by Chanthini KANAGARAJ
more than 80 years of intensive use, many pests and pathogens have developed resistance to the
currently used chemistries. Thus, we explored the isolation and bioactivity of a chemical compound,
Precocene I, isolated from the perennial grass, Desmosstachya bipinnata (L.) Stapf. Fractions produced
from chloroform extractions showed suppressive activity on larvae of Spodoptera litura (Lepidoptera:
Noctuidae), the Oriental armyworm. Column chromatography analyses identified Precocene I
confirmed using FTIR, HPLC and NMR techniques. The bioactivity of the plant-extracted Dp-
Precocene I was compared to a commercially produced Precocene I standard. The percentage of
mortality observed in insects fed on plant tissue treated with 60 ppm Db-Precocene I was 97, 87 and
81, respectively, for the second, third and fourth instar larvae. The LC50 value of third instars was
23.2 ppm. The percentages of survival, pupation, fecundity and egg hatch were altered at sub-lethal
concentrations of Db-Precocene I (2, 4, 6 and 8 ppm, sprays on castor leaves). The observed effects
were negatively correlated with concentration, with a decrease in effects as concentrations increased.
Distinct changes in feeding activity and damage to gut tissues were observed upon histological
examination of S. litura larvae after the ingestion of Db-Precocene I treatments. Comparative analyses
of mortality on a non-target organism, the earthworm, Eisenia fetida, at equal concentrations of
Precocene I and two chemical pesticides (cypermethrin and monocrotophos) produced mortality
only with the chemical pesticide treatments.
bioactivity. FAs are dynamic members of all biota, as well as being acknowledged for their critical function
in initiating phytohormone interactions and acting as important participants in many defense signalling pathways
of the plant system. The current study looks at the defense-eliciting potentials of fatty acids from the green seaweed
Chaetomorpha antennina (Bory) Kützing and their impact on the polyphagous insect pest Spodoptera litura (Fab).
Results The seaweed was detected with 19 fatty acids, with larger proportion of hexa and octadecanoic and linoleic
acids. The algal fatty acid compounds (CFA) were successful in eliciting salicylic acid and phenolic compounds
biosynthesis along with defense enzymes peroxidase (PO) and polyphenol oxidase (PPO). CFA enhanced the synthesis
of defense enzymes, PO and PPO and phenols, post infestation with S. litura (> 50%) compared to control plants
exposed to the pest. CFA was also effective in causing direct mortalities (96–98%) to the larvae (II-V instars). S.
litura larvae exposed to elicited tomato plants displayed physiological incursions that extended larval-pupal
duration to 26–28 days, preventing both morphogenetic transitions as well as affecting their morphology, that lead
to the emergence of adults with malformed wings, legs. As a consequence, the fecundity was reduced by 60%
affecting the reproductive performances of second-generation adults. The consumption rate (RCR) of larvae
exposed to CFA was decreased by 84%, depicting feeding deterrence. These larvae were also observed with > 50%
reduction in the levels of phosphatase enzyme secretion, bringing down larval growth rate from 0.58 to 0.34 mg/day.
Histological analysis of exposed larvae displayed midgut cell disruption.
Conclusion Hence, the study finally confirms the elicitor potentials of fatty acid compounds from C.
antennina, by inducing natural systemic defenses. This investigation unlocks novel forecasts besides delivering
an unconventional method for crop protection to moderate or interchange the solicitation of chemical pesticides.
as excellent sources of bioactive compounds that can stimulate plant growth and also enhance their resistance
against biotic and abiotic stressors. Compounds derived from the marine algae Chaetomorpha antennina (Cladophoraceae)
were analysed for their biocontrol efficiency against the tomato disease pathogen Alternaria solani
as an alternate technique to preserve agricultural output sustainability.
Results The active fraction from the methanol extract of C. antennina (CA-F8) proved effective against the pathogen
in vitro by affecting A. solani’s spore germination (92.13%) along with their mycelial growth thereby decreasing their
dry weight (44.71%). GC–MS examination revealed the presence of fatty acids (defence pathway activators), terpenes
(antimicrobial compound) and antioxidants (deactivators of pathogen enzymes). Seaweed compounds also elicited
polyphenol oxidase (PPO) (78.8%) and peroxidase (PO) (54.6%) synthesis, along with stimulating the accumulation
of foliar phenols (67.5%) that are components of jasmonic acid defense pathway, higher compared to control plants.
Salicylic acid was detected only in treated plants, thereby offering efficient disease control.
Conclusions By triggering natural systemic defences, salicylate (SA) and jasmonate (JA) mediated pathways;
the study demonstrates the elicitor potentials of chemicals from C. antennina that was efficient in controlling early
blight (EB) disease. In addition to providing a different method for crop protection to reduce or replace the demand
for chemical pesticides, this study reveals unique projections
important challenges faced in rice cultivation. A novel and eco-friendly strategy to synthesise ‘Fungal
Chitosan’ (FC) from Aspergillus niger using rice straw could serve as a sustainable treatment approach
to improve both disease resistance and yields, while also effectively managing the rice stubble waste.
The FC treatment promoted germination as well as growth parameters in rice varieties, TN1 (high
yielding-susceptible) and PTB33 (low yielding-resistant) better than a commercial chitosan (PC).
Treatments of exogenously applied FC to plants produced direct toxicity to Xoo, and reduced the
BLB disease index by 39.9% in TN1. The capability of FC to trigger a cascade of defense pathways
was evident from the measurable changes in the kinetics of defense enzymes, peroxidase (POD)
and polyphenol oxidase (PPO). FC treatment increased levels of POD in TN1 by 59.4%, which was
35.3% greater than that of untreated PTB33. Therefore, the study demonstrated the effectiveness
of FC treatments for use in agriculture as a potential biostimulant as well as protective agent against
bacterial leaf blight, BLB, of rice (Oryza sativa) that could be produced from stubble waste and
improve rice stubble management strategies.
application is growing in surplus amounts, increasing the agricultural expenses and damaging the environment.
Organic fertilizers, obtained from natural sources, encompass all essential plant nutrients. Application of aqueous
seaweed extracts are regarded as potential plant biostimulant agents. The liquid seaweed extract of green
seaweed Chaetomorpha antennina (CA-LSE) were evaluated for their biostimulant activity on seed germination
and growth of tomato. The CA-LSEs were able to stimulate early emergence of tomato seeds, in addition to
increasing their germination percentage and energy. They also exerted a positive influence on the vegetative
growth, resulting in increased plant height, leaf-branch number and yield. The CA-LSEs were influence the
plant's biochemical profile and displayed a linear increase in pigment contents (chlorophyll a & b and carotenoids),
total soluble solids (TSS), phenols as well as ascorbic acid contents. The bio-stimulant potential was
attributed to the elements present in CA-LSEs, elucidated by EDX analysis that revealed the presence of six
elements (O, Na, Mg, S, Cl and Ca), that were essentially plant nutrients. These results support the bio-stimulant
potential of C. antennina, which can be applied as a prospective bio-fertilizer that is economic, renewable,
efficient and eco-friendly, and also can be regarded as a potential catalyst for the betterment of sustainable
agricultural food production.
Utilization of wild gene pool, together with the application of sustainable and eco-friendly agronomic
crop improvement strategies, is being focused on to tackle mounting food insecurity issues. In this
aspect, the green seaweed, Ulva flexuosa, was assessed for plant biostimulant potential on cherry
tomato, in terms of seed priming e ects, nutrition and yield. SEM-EDX analysis of U. flexuosa
presented the occurrence of cell wall elements (O, Na, Mg, S, Cl, K and Ca). The phytochemical
analyses of liquid seaweed extract (EF-LSE) revealed the presence of carbohydrates, protein, phenols,
flavonoids, saponins, tannins and coumarins. The EF-LSEs were found to stimulate seed germination
in a dose-dependent manner, recording higher seed germination, and biomass and growth parameters.
The seedlings of treated seeds altered the biochemical profile of the fruit, in terms of TSS (93%),
phenol (92%), lycopene (12%) and ascorbic acid (86.8%). The EF-LSEs positively influenced fruit
yield (97%). Henceforth, this investigation brings to light the plant biostimulant potential of the
under-utilized seaweed source, U. flexuosa, to be useful as a bio fertilizer in agronomic fields for a
cumulative enhancement of crop vigour as well as yields to meet the growing food demands.
agricultural practices. The green seaweed Chaetomorpha antennina found in abundance in coastal areas of India
has been reported with various bioactivities. Owing to the requirement of alternative and economical natural pest
control method to be applied in sustainable agronomic strategies, the current study attempts to evaluate the efficacy
of chemical toxins from C. antennina, as insecticidal agents, by inspecting their effects on the physiology, biochemistry,
immune system, and histology of one of the most important insect pests of agricultural crops in the Asian tropics,
the polyphagous lepidopteran Spodoptera litura.
Results: The active fraction 5 isolated from C. antennina using methanol extraction produced significant mortality
rates of S. litura among all the other fractions obtained. GC–MS analysis revealed the presence of various pesticide
compounds. The toxin compounds (active fraction 5) were found to negatively influence the pest’s immune system
performance at sub-lethal concentrations (
LC50 38.73and LC90
53.60 ppm), affecting insect development, reducing
the haemocyte count (69.24%) and reduced the activity of major defence enzyme phenoloxidase decreased posttreatments.
Digestive phosphatase enzymes, acid phosphatase, ACP, alkaline phosphatase, ALP, and ATPase were
demodulated by 37.5, 39, and 23.9% compared with untreated. Increase in detoxification enzymes coupled with midgut
collapse are indicative of the toxicity of the compounds. Earthworms exposed to seaweed compounds displayed
no debarring effects.
Conclusion: Extracted seaweed compounds produced significant lethal effect on the insect larvae, affecting the
immune as well as digestive systems of the pest. However, no such toxicity was observed in earthworms treated with
the seaweed fraction supporting their environmentally benign nature. Since the insect immune system is responsible for the development of resurgence against pesticides, suppression of immunological activities by seaweed toxins
indicate the long-term applicability of these compounds as prospective pesticides. The results support the potential
of chemicals from C. antennina for biopesticide development to manage economically important agricultural pests.
The efficacy of halotolerant marine macroalgal extract of Chaetomorpha antennina (Seaweed Extract—
SWE) in mitigating the toxic effects of salt stress (150 mM) in tomato plants to promote and enhance
both plant functionality and yield was tested. It was evident that salt stress undesirably affected
germination and plant growth in terms of quality and quantity. Treatment with SWE improved the
functionality of salt-strained tomato plants by enhancing their germination indexes, growth and
morphological traits, and photosynthetic pigments, as well as protein and phenol concentrations. SWE
also exerted a positive influence on protecting the plant against salt stress by increasing the synthesis
and accumulation of antioxidant enzymes, superoxide dismutase and lipoxygenase enzymes, along
with the contents of lycopene and vitamin C. SWE also increased the nutraceutical quality, flavour and
organolepty of emerged tomato fruits. GCMS analysis of fruit pericarp showed increased siloxane,
phenol, antioxidant and indole acetic acid compounds, along with aromatic benzene compounds.
These results indicate the potentiality of SWE in protecting plants against salt stress induced toxicities
by prompting the synthesis of protective compounds such as siloxane and antioxidant enzymes.
It was also noted that SWE plays a crucial role in promoting plant growth and survivability by
improving plant functionality, yield and nutrition, by promoting cultivation in saline soils in an
eco-friendly and sustainable manner.
growth is affected by salt stress at all stages of development. The contemporary investigation focused
on Chaetomorpha antennina aqueous extracts (SWEs) to decrease the effects of salt strain on rice germination,
growth, yield, and the production of key biological and biochemical characters of the rice,
Oryza sativa L. (Poaceae). SWE improved the germination capacities of rice seedlings by promoting
their emergence 36.27 h prior to those that had been exposed to saline stress. The creation of 79.647%
longer radicles by SWE treatment on salt-stressed seeds which boosted the establishment effectiveness
of seeds produced under salt stress longer radicles resulted in plants that were 64.8% taller. SWE
treatment was effective in revoking the levels of protein (26.9%), phenol (35.54%), and SOD (41.3%)
enzyme levels that were previously constrained by salinity stress. Additionally, SWE were also
efficient in retaining 82.6% of leaf water content and enhancing the production of photosynthetic
pigments affected by salt exposure earlier. The improvement in plant functionality was evident from
the display of increase in tiller numbers/hill (62.36%), grain yield (58.278%), and weight (56.502%).
The outcome of our research shows that SWEs protected the plants from the debarring effects of salinity
by enhancing the plant functionality and yield by mechanistically enriching their physiological
(germination and vegetative growth) and biochemical attributes (leaf RWC, photosynthetic pigments,
protein, phenol, and SOD). Despite the increase in TSS and starch levels in rice grain exposed to
salinity stress, SWE improved the grain protein content thus cumulatively enhancing rice nutrition
and marketability. The current investigation reveals that the extracts of C. antennina can help alleviate
rice plants from salt stress in an efficient, eco-friendly, as well as economical way.
more than 80 years of intensive use, many pests and pathogens have developed resistance to the
currently used chemistries. Thus, we explored the isolation and bioactivity of a chemical compound,
Precocene I, isolated from the perennial grass, Desmosstachya bipinnata (L.) Stapf. Fractions produced
from chloroform extractions showed suppressive activity on larvae of Spodoptera litura (Lepidoptera:
Noctuidae), the Oriental armyworm. Column chromatography analyses identified Precocene I
confirmed using FTIR, HPLC and NMR techniques. The bioactivity of the plant-extracted Dp-
Precocene I was compared to a commercially produced Precocene I standard. The percentage of
mortality observed in insects fed on plant tissue treated with 60 ppm Db-Precocene I was 97, 87 and
81, respectively, for the second, third and fourth instar larvae. The LC50 value of third instars was
23.2 ppm. The percentages of survival, pupation, fecundity and egg hatch were altered at sub-lethal
concentrations of Db-Precocene I (2, 4, 6 and 8 ppm, sprays on castor leaves). The observed effects
were negatively correlated with concentration, with a decrease in effects as concentrations increased.
Distinct changes in feeding activity and damage to gut tissues were observed upon histological
examination of S. litura larvae after the ingestion of Db-Precocene I treatments. Comparative analyses
of mortality on a non-target organism, the earthworm, Eisenia fetida, at equal concentrations of
Precocene I and two chemical pesticides (cypermethrin and monocrotophos) produced mortality
only with the chemical pesticide treatments.
bioactivity. FAs are dynamic members of all biota, as well as being acknowledged for their critical function
in initiating phytohormone interactions and acting as important participants in many defense signalling pathways
of the plant system. The current study looks at the defense-eliciting potentials of fatty acids from the green seaweed
Chaetomorpha antennina (Bory) Kützing and their impact on the polyphagous insect pest Spodoptera litura (Fab).
Results The seaweed was detected with 19 fatty acids, with larger proportion of hexa and octadecanoic and linoleic
acids. The algal fatty acid compounds (CFA) were successful in eliciting salicylic acid and phenolic compounds
biosynthesis along with defense enzymes peroxidase (PO) and polyphenol oxidase (PPO). CFA enhanced the synthesis
of defense enzymes, PO and PPO and phenols, post infestation with S. litura (> 50%) compared to control plants
exposed to the pest. CFA was also effective in causing direct mortalities (96–98%) to the larvae (II-V instars). S.
litura larvae exposed to elicited tomato plants displayed physiological incursions that extended larval-pupal
duration to 26–28 days, preventing both morphogenetic transitions as well as affecting their morphology, that lead
to the emergence of adults with malformed wings, legs. As a consequence, the fecundity was reduced by 60%
affecting the reproductive performances of second-generation adults. The consumption rate (RCR) of larvae
exposed to CFA was decreased by 84%, depicting feeding deterrence. These larvae were also observed with > 50%
reduction in the levels of phosphatase enzyme secretion, bringing down larval growth rate from 0.58 to 0.34 mg/day.
Histological analysis of exposed larvae displayed midgut cell disruption.
Conclusion Hence, the study finally confirms the elicitor potentials of fatty acid compounds from C.
antennina, by inducing natural systemic defenses. This investigation unlocks novel forecasts besides delivering
an unconventional method for crop protection to moderate or interchange the solicitation of chemical pesticides.
as excellent sources of bioactive compounds that can stimulate plant growth and also enhance their resistance
against biotic and abiotic stressors. Compounds derived from the marine algae Chaetomorpha antennina (Cladophoraceae)
were analysed for their biocontrol efficiency against the tomato disease pathogen Alternaria solani
as an alternate technique to preserve agricultural output sustainability.
Results The active fraction from the methanol extract of C. antennina (CA-F8) proved effective against the pathogen
in vitro by affecting A. solani’s spore germination (92.13%) along with their mycelial growth thereby decreasing their
dry weight (44.71%). GC–MS examination revealed the presence of fatty acids (defence pathway activators), terpenes
(antimicrobial compound) and antioxidants (deactivators of pathogen enzymes). Seaweed compounds also elicited
polyphenol oxidase (PPO) (78.8%) and peroxidase (PO) (54.6%) synthesis, along with stimulating the accumulation
of foliar phenols (67.5%) that are components of jasmonic acid defense pathway, higher compared to control plants.
Salicylic acid was detected only in treated plants, thereby offering efficient disease control.
Conclusions By triggering natural systemic defences, salicylate (SA) and jasmonate (JA) mediated pathways;
the study demonstrates the elicitor potentials of chemicals from C. antennina that was efficient in controlling early
blight (EB) disease. In addition to providing a different method for crop protection to reduce or replace the demand
for chemical pesticides, this study reveals unique projections
important challenges faced in rice cultivation. A novel and eco-friendly strategy to synthesise ‘Fungal
Chitosan’ (FC) from Aspergillus niger using rice straw could serve as a sustainable treatment approach
to improve both disease resistance and yields, while also effectively managing the rice stubble waste.
The FC treatment promoted germination as well as growth parameters in rice varieties, TN1 (high
yielding-susceptible) and PTB33 (low yielding-resistant) better than a commercial chitosan (PC).
Treatments of exogenously applied FC to plants produced direct toxicity to Xoo, and reduced the
BLB disease index by 39.9% in TN1. The capability of FC to trigger a cascade of defense pathways
was evident from the measurable changes in the kinetics of defense enzymes, peroxidase (POD)
and polyphenol oxidase (PPO). FC treatment increased levels of POD in TN1 by 59.4%, which was
35.3% greater than that of untreated PTB33. Therefore, the study demonstrated the effectiveness
of FC treatments for use in agriculture as a potential biostimulant as well as protective agent against
bacterial leaf blight, BLB, of rice (Oryza sativa) that could be produced from stubble waste and
improve rice stubble management strategies.
application is growing in surplus amounts, increasing the agricultural expenses and damaging the environment.
Organic fertilizers, obtained from natural sources, encompass all essential plant nutrients. Application of aqueous
seaweed extracts are regarded as potential plant biostimulant agents. The liquid seaweed extract of green
seaweed Chaetomorpha antennina (CA-LSE) were evaluated for their biostimulant activity on seed germination
and growth of tomato. The CA-LSEs were able to stimulate early emergence of tomato seeds, in addition to
increasing their germination percentage and energy. They also exerted a positive influence on the vegetative
growth, resulting in increased plant height, leaf-branch number and yield. The CA-LSEs were influence the
plant's biochemical profile and displayed a linear increase in pigment contents (chlorophyll a & b and carotenoids),
total soluble solids (TSS), phenols as well as ascorbic acid contents. The bio-stimulant potential was
attributed to the elements present in CA-LSEs, elucidated by EDX analysis that revealed the presence of six
elements (O, Na, Mg, S, Cl and Ca), that were essentially plant nutrients. These results support the bio-stimulant
potential of C. antennina, which can be applied as a prospective bio-fertilizer that is economic, renewable,
efficient and eco-friendly, and also can be regarded as a potential catalyst for the betterment of sustainable
agricultural food production.
Utilization of wild gene pool, together with the application of sustainable and eco-friendly agronomic
crop improvement strategies, is being focused on to tackle mounting food insecurity issues. In this
aspect, the green seaweed, Ulva flexuosa, was assessed for plant biostimulant potential on cherry
tomato, in terms of seed priming e ects, nutrition and yield. SEM-EDX analysis of U. flexuosa
presented the occurrence of cell wall elements (O, Na, Mg, S, Cl, K and Ca). The phytochemical
analyses of liquid seaweed extract (EF-LSE) revealed the presence of carbohydrates, protein, phenols,
flavonoids, saponins, tannins and coumarins. The EF-LSEs were found to stimulate seed germination
in a dose-dependent manner, recording higher seed germination, and biomass and growth parameters.
The seedlings of treated seeds altered the biochemical profile of the fruit, in terms of TSS (93%),
phenol (92%), lycopene (12%) and ascorbic acid (86.8%). The EF-LSEs positively influenced fruit
yield (97%). Henceforth, this investigation brings to light the plant biostimulant potential of the
under-utilized seaweed source, U. flexuosa, to be useful as a bio fertilizer in agronomic fields for a
cumulative enhancement of crop vigour as well as yields to meet the growing food demands.
agricultural practices. The green seaweed Chaetomorpha antennina found in abundance in coastal areas of India
has been reported with various bioactivities. Owing to the requirement of alternative and economical natural pest
control method to be applied in sustainable agronomic strategies, the current study attempts to evaluate the efficacy
of chemical toxins from C. antennina, as insecticidal agents, by inspecting their effects on the physiology, biochemistry,
immune system, and histology of one of the most important insect pests of agricultural crops in the Asian tropics,
the polyphagous lepidopteran Spodoptera litura.
Results: The active fraction 5 isolated from C. antennina using methanol extraction produced significant mortality
rates of S. litura among all the other fractions obtained. GC–MS analysis revealed the presence of various pesticide
compounds. The toxin compounds (active fraction 5) were found to negatively influence the pest’s immune system
performance at sub-lethal concentrations (
LC50 38.73and LC90
53.60 ppm), affecting insect development, reducing
the haemocyte count (69.24%) and reduced the activity of major defence enzyme phenoloxidase decreased posttreatments.
Digestive phosphatase enzymes, acid phosphatase, ACP, alkaline phosphatase, ALP, and ATPase were
demodulated by 37.5, 39, and 23.9% compared with untreated. Increase in detoxification enzymes coupled with midgut
collapse are indicative of the toxicity of the compounds. Earthworms exposed to seaweed compounds displayed
no debarring effects.
Conclusion: Extracted seaweed compounds produced significant lethal effect on the insect larvae, affecting the
immune as well as digestive systems of the pest. However, no such toxicity was observed in earthworms treated with
the seaweed fraction supporting their environmentally benign nature. Since the insect immune system is responsible for the development of resurgence against pesticides, suppression of immunological activities by seaweed toxins
indicate the long-term applicability of these compounds as prospective pesticides. The results support the potential
of chemicals from C. antennina for biopesticide development to manage economically important agricultural pests.
The efficacy of halotolerant marine macroalgal extract of Chaetomorpha antennina (Seaweed Extract—
SWE) in mitigating the toxic effects of salt stress (150 mM) in tomato plants to promote and enhance
both plant functionality and yield was tested. It was evident that salt stress undesirably affected
germination and plant growth in terms of quality and quantity. Treatment with SWE improved the
functionality of salt-strained tomato plants by enhancing their germination indexes, growth and
morphological traits, and photosynthetic pigments, as well as protein and phenol concentrations. SWE
also exerted a positive influence on protecting the plant against salt stress by increasing the synthesis
and accumulation of antioxidant enzymes, superoxide dismutase and lipoxygenase enzymes, along
with the contents of lycopene and vitamin C. SWE also increased the nutraceutical quality, flavour and
organolepty of emerged tomato fruits. GCMS analysis of fruit pericarp showed increased siloxane,
phenol, antioxidant and indole acetic acid compounds, along with aromatic benzene compounds.
These results indicate the potentiality of SWE in protecting plants against salt stress induced toxicities
by prompting the synthesis of protective compounds such as siloxane and antioxidant enzymes.
It was also noted that SWE plays a crucial role in promoting plant growth and survivability by
improving plant functionality, yield and nutrition, by promoting cultivation in saline soils in an
eco-friendly and sustainable manner.
growth is affected by salt stress at all stages of development. The contemporary investigation focused
on Chaetomorpha antennina aqueous extracts (SWEs) to decrease the effects of salt strain on rice germination,
growth, yield, and the production of key biological and biochemical characters of the rice,
Oryza sativa L. (Poaceae). SWE improved the germination capacities of rice seedlings by promoting
their emergence 36.27 h prior to those that had been exposed to saline stress. The creation of 79.647%
longer radicles by SWE treatment on salt-stressed seeds which boosted the establishment effectiveness
of seeds produced under salt stress longer radicles resulted in plants that were 64.8% taller. SWE
treatment was effective in revoking the levels of protein (26.9%), phenol (35.54%), and SOD (41.3%)
enzyme levels that were previously constrained by salinity stress. Additionally, SWE were also
efficient in retaining 82.6% of leaf water content and enhancing the production of photosynthetic
pigments affected by salt exposure earlier. The improvement in plant functionality was evident from
the display of increase in tiller numbers/hill (62.36%), grain yield (58.278%), and weight (56.502%).
The outcome of our research shows that SWEs protected the plants from the debarring effects of salinity
by enhancing the plant functionality and yield by mechanistically enriching their physiological
(germination and vegetative growth) and biochemical attributes (leaf RWC, photosynthetic pigments,
protein, phenol, and SOD). Despite the increase in TSS and starch levels in rice grain exposed to
salinity stress, SWE improved the grain protein content thus cumulatively enhancing rice nutrition
and marketability. The current investigation reveals that the extracts of C. antennina can help alleviate
rice plants from salt stress in an efficient, eco-friendly, as well as economical way.