Papers by Antonious al-Daoude
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
A proteomic analysis was conducted to map up events set off during the initial stages of interact... more A proteomic analysis was conducted to map up events set off during the initial stages of interaction between the fungal pathogen Cochliobolus sativus and the susceptible barley cultivar WI2291. Two-dimensional polyacrylamide gel electrophoresis experiments were carried to detect proteins differentially expressed under inoculated and non-inoculated conditions. Twenty-seven out of 100 protein spots were consistently observed as differential in the proteome profiles of the studied treatments. After tryptic digestion, MALDI-TOF/MS analysis and MASCOT database searching identified proteins with presumed functions relating to signal transduction, proteins involved in energy metabolism, secondary metabolism and protein synthesis. However, expression of genes involved in protection against cell damage was not detected, indicating that there may be a higher degradation of cellular components in the susceptible genotype. Proteomic results from this study indicate a complex response of suscept...
Leaf scald caused by the infection of Rhynchosporium secalis, is a worldwide crop disease resulti... more Leaf scald caused by the infection of Rhynchosporium secalis, is a worldwide crop disease resulting in sig-nificant loss of barley yield. In this study, a systematic sequencing of expressed sequence tags (ESTs) was cho-sen to obtain a global picture of the assembly of genes involved in pathogenesis. To identify a large number of plant ESTs, which are induced at different time points, an amplified fragment length polymorphism (AFLP) display of complementary DNA (cDNA) was utilized. Transcriptional changes of 140 ESTs were observed, of which 19 have no previously described function. Func-tional annotation of the transcripts revealed a variety of infection-induced host genes encoding classical patho-genesis-related (PR) or genes that play a role in the sig-nal transduction pathway. The expression analyses by a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) revealed that Rar1 and Rpg4 are defense inducible genes, and were consistent with the cDNA-AFLP data in...
Spot blotch caused by the hemibiotrophic pathogen Cochliobolus sativus has been the major yield-r... more Spot blotch caused by the hemibiotrophic pathogen Cochliobolus sativus has been the major yield-reducing factor for barley production during the last decade. Monitoring transcriptional reorganization triggered in response to this fungus is an essential first step for the functional analysis of genes involved in the pro-cess. To characterize the defense responses initiated by barley resistant and susceptible cultivars, a survey of transcript abundance at early time points of C. sativus inoculation was conducted. A notable number of tran-scripts exhibiting significant differential accumulations in the resistant and susceptible cultivars were detected compared to the non-inoculated controls. At the p-value of 0.0001, transcripts were divided into three general categories; defense, regulatory and unknown function, and the resistant cultivar had the greatest number of common transcripts at different time points. Quanti-ties of differentially accumulated gene transcripts in both cultivars...
Heavy metals are among the highly dangerous pollutants although various physical and chemical rem... more Heavy metals are among the highly dangerous pollutants although various physical and chemical remediation methods are available, phytoremediation is so far one of the easiest, safest, and cheapest methods for heavy metal remediation polluted sites. In this research, heavy metal phytoremediation potentials of the previously generated CYP4502E1 expressed in A. thaliana and S. grandiflora plants were evaluated. For this purpose, both transgenic plants were grown under greenhouse-controlled conditions. Firstly, plant phytoremediation potentials were evaluated under different irrigation inputs of Mn (75, 100, and 125 ppm); Cu (75, 100, and 125 ppm); and Pb (30, 40, and 50 ppm). Additionally, plants phytoremediation potentials of Zn (41.9 ppm) and Br (51.3 ppm) removal were evaluated overtime after 5, 10, and 15 days of growth. Results showed a significant increase in Mn, Cu, and Pb plant content in both plants with increasing contaminant inputs. Pb content in pot soil where S. grandiflor...
Journal of Plant Diseases and Protection, 2017
Late blight, caused by Phytophthora infestans (Mont.) de Bary, is a devastating disease found wor... more Late blight, caused by Phytophthora infestans (Mont.) de Bary, is a devastating disease found worldwide. During 2011, 2013 and 2014 cropping seasons, prevalence of potato late blight in all survived areas throughout the interior of Syria was examined and the disease incidence varied and ranged from 0 to 85.71%. Potato leave samples showing late blight symptoms were collected from five different regions known to grow potato intensively. Based on their morphological characteristics, 22 isolates were distinguished as P. infestans. Using two fungal specific primers, ITS3 and PINF2 in a PCR assay, all isolates were confirmed as P. infestans, while they produce * 450 bp band. Similarly, all confirmed P. infestans isolates were able to produce a 170-bp band when INF-1 and INF-2 primers were deployed indicating that studied isolates had merely mating type A1 and no isolate with mating type A2 was found which might explain the absence of oospores in considered areas.
Powdery mildew, caused by Blumeria graminis f. sp. hordei (Bgh) is a common foliar disease of bar... more Powdery mildew, caused by Blumeria graminis f. sp. hordei (Bgh) is a common foliar disease of barley worldwide. To better understand barley mechanisms to resist this disease, compatible/incompatible barley-Bgh interactions and some marker genes involved in salicylic acid (SA) pathway were evaluated using qRT-PCR across four-time points after pathogen challenge. Data showed that SA level contents of tolerant and susceptible genotypes increased one day post inoculation (dpi) in comparison with non-inoculated plants, and that the tolerant genotype contained three-fold of total SA than the susceptible one. This might be evidence that SA plays a positive role in signaling events during fungal infection by Bgh. In general, our study shows a remarkable discrepancy in the expression pattern of those marker genes between compatible and incompatible barley-Bgh interactions. The results of qPCR revealed that the defense-related genes PR2, PAL and LSD1 were expressed in the tolerant genotype ov...
A proteomic analysis was conducted to map up events set off during the initial stages of interact... more A proteomic analysis was conducted to map up events set off during the initial stages of interaction between the fungal pathogen Cochliobolus sativus and the susceptible barley cultivar WI2291. Two-dimensional polyacrylamide gel electrophoresis experiments were carried to detect proteins differentially expressed under inoculated and non-inoculated conditions. Twenty-seven out of 100 protein spots were consistently observed as differential in the proteome profiles of the studied treatments. After tryptic digestion, MALDI-TOF/MS analysis and MASCOT database searching identified proteins with presumed functions relating to signal transduction, proteins involved in energy metabolism, secondary metabolism and protein synthesis. However, expression of genes involved in protection against cell damage was not detected, indicating that there may be a higher degradation of cellular components in the susceptible genotype. Proteomic results from this study indicate a complex response of suscept...
Spot blotch (SB) caused by the fungus Cochliobolus sativus, is an economically important disease ... more Spot blotch (SB) caused by the fungus Cochliobolus sativus, is an economically important disease on barley worldwide. Molecular analysis of SB resistance using quantitative trait locus (QTL) analysis can improve the efficiency of the breeding process. In the current work, and to accelerate development of SB-resistant barley cultivars, AFLP markers linked to SB resistance have been identified by using F2 recombinant inbred lines derived from a cross between the resistant barley cv. Banteng and the susceptible cv. WI2291. Single marker analysis (SMA) based on t-test revealed that out of 82 AFLP markers; five AFLP markers AAC × CTG (700 bp), ACT × CAT (600 bp), ACT × CAT (400 bp), ACT × CTG (550 bp) and AGG × CAG (490 bp) were identified. The data showed that SMA-based t-test could be a useful analysis for dominant markers such AFLP in breeding programs, and that the AFLP detected markers can be employed in genomics-assisted breeding for selection of SB-resistant barley genotypes.
Broad spectrum of different fungal pathogenic lifestyles can infect barley plants, most of which ... more Broad spectrum of different fungal pathogenic lifestyles can infect barley plants, most of which are responsible for significant annual crop losses. Understanding of gene expression that take place at the earliest stages of infection would be a necessary step for describing the initial mechanism between barley and the pathogen interactions. The purpose of the present work was to monitor the expression of some well-identified genes PR1, PR2, PR3,PR5, PAL and SGT1 during interaction of resistant barley plants with three economically important diseases viz. spot blotch (Cochliobolus sativus), scald (Rhynchosporium secalis) and powdery mildew (Blumeria graminis) at very early stages of disease development. Data demonstrated a remarkable contradiction in the gene expression patterns between barley and pathogens interactions 12 and 24 hours post inoculation (hpi), and all of them showed significant differential expressions compared to the control plants. The most significant differences w...
Cereal Research Communications
Barley plants can be infected by a variety of fungal pathogens with different lifestyles. The bio... more Barley plants can be infected by a variety of fungal pathogens with different lifestyles. The biotrophic Blumeria graminis, necrotrophic Pyrenopora teres, and hemibiotrophic Cochliobolus sativus are economically important pathogens of barley worldwide. Currently, the mechanisms underlying resistance to these diseases are still largely unknown. In the current study, expression patterns of some well-known pathogenesis-related (PR) genes were monitored at early points of infection in resistant and susceptible barley genotypes using quantitative PCR method. Data showed earlier and higher accumulation of PR transcripts in the resistant genotype as compared with the susceptible one, and the expression patterns of the same defense-associated genes were altered in adaptation to each pathogen. The most outstanding differences were observed in PR1 and PR5 genes that were highly activated in resistant plants infected with the hemibiotrophic pathogen rather than the biotrophic and necrotrophic ones. The barley defense response mechanisms against these pathogens could be in agreement with the well-accepted concept that these events are intense in the resistant cultivar. This work might provide useful information for a deeper molecular research on barley defense responses toward pathogens with different lifestyles.
Hellenic Plant Protection Journal
Net blotch (NB), caused by the necrotrophic fungal pathogen Pyrenophora teres f. teres, substanti... more Net blotch (NB), caused by the necrotrophic fungal pathogen Pyrenophora teres f. teres, substantially reduces barley grain yield and quality worldwide. The role of salicylic acid (SA) signaling in NB resistance has been poorly documented. In this study, SA levels as well as the expression of the SA-responsive gene PR2 were monitored in infected leaves of two barley genotypes, Banteng (resistant) and WI2291 (susceptible), at different time points of infection. SA signaling was activated in bothgenotypes 24 hours post infection (hpi) as compared with non-inoculated plants. However, with or without pathogen pretreatment, SA signifi cantly increased (P=0.001) in Banteng comparing with WI2291. RT-PCR analysis revealed that PR2 expression increases in the resistant and susceptible genotypes over the inoculation time points, with maximum expression (6.4 and 1.99-fold, respectively) observed 6 dpi. PR2 expression was paralleled by an increase in leaf SA content as shown by the test coincide...
Hellenic Plant Protection Journal
Rhynchosporium secalis, the causal agent of barley scald disease, is a fungus commonly found in t... more Rhynchosporium secalis, the causal agent of barley scald disease, is a fungus commonly found in the environment. Disease spread within a field and between fields occurs through the aerial dispersal of the fungal spores. However, not much is known about the survival potential of fungal conidia exposed to solar radiation. In the present study, detached conidia of R. secalis were exposed simultaneously in the field to direct sunlight or placed in an adjacent ventilated enclosure in the dark for periods ranging from 0.5 to 8h. In addition, conidia were either exposed or not exposed to UV-C light (254 nm) for periods ranging between 0.5 and 60 min in the laboratory. After exposure, conidia were placed on water agar Petri dishes and allowed to germinate for 24h. Germinability of conidia was reduced by up to 94% after 8h of exposure to solar irradiance (670-860 Wm-2) in the field in comparison to the non-exposed control. Germinability of conidia in the laboratory was reduced up to ~100% by...
Acta Phytopathologica et Entomologica Hungarica
The seed-borne (Pyrenophora graminea; Pg) and foliar (Blumeria graminis; Bg) are two economically... more The seed-borne (Pyrenophora graminea; Pg) and foliar (Blumeria graminis; Bg) are two economically important fungal pathogens of barley worldwide. Barley plant resistance genes, as the pathogenesis related proteins play an important role in defense mechanisms. This study aimed to monitor the expression of PR2 and PAL pathogenesis related genes during compatible/incompatible barley interaction with Pg and Bg at different time points of disease development using the Quantitative Real-time PCR technique (qRT-PCR). Comparison of data showed that PR2 and PAL were significantly over expressed in infected resistant and susceptible plants as against their lower expression in controls,. Upregulation of these defense-related genes during Pg and Bg infections was companied with a slow development of disease symptoms at the time course in the resistant genotype. qRT-PCR analysis revealed higher gene expression in resistant barley plants inoculated with Pg as compared with Bg, with a maximum expression for PR2 (13.8 and 5.06-fold) and PAL (14.8 and 4.51-fold) respectively, at the latest stage of each disease development. It was also noteworthy that PR2 and PAL genes, had higher constitutive expression and faster induction for the both pathogens in the resistant genotype as compared with the susceptible one. Obtained results suggest that both genes, PR2 and PAL, positively regulate Pg-and Bg-resistance in barley plants during disease progress. These expression patterns can provide useful insights to better understanding of the barley-fungus interactions with different fungal lifestyles.
Cereal Research Communications
The biotrophic Blumeria graminis (Bg) and the necrotrophic Cochliobolus sativus; (Cs) are economi... more The biotrophic Blumeria graminis (Bg) and the necrotrophic Cochliobolus sativus; (Cs) are economically important fungal pathogens of barley globally. To better understand barley mechanisms to resist these pathogens, changes in salicylic acid (SA) and its responsive genes particularly the pathogenesis related PR1, PR2, PR3 and PR5 were evaluated using qRT-PCR across four time points post infection. Data showed that SA contents significantly increased (P = 0.001) in infected plants of both resistant and susceptible genotypes 24 h post inoculation in comparison with non-infected controls. In addition, time-course tests revealed a notable contradiction in the defense-related genes expression patterns between barley and Bg and Cs interactions, showing that expression patterns of the same defense-associated genes were altered in adaptation to different pathogens. PR1 and PR2 genes were highlyactivated inresistant plants infected with the necrotrophic pathogen Cs rather than of the biotrophic one. The uniformity in barley defense response mechanisms could be in convention with the well-accepted notion that these responses are high intense in the resistant genotype. Our work provides useful information on the expected role of SA pathways in barley towards biotrophic and necroptrophic pathogens with different lifestyles.
Cereal Research Communications
Spot blotch (SB) caused by the hemibiotrophic fungal pathogen Cochliobolus sativus is a destructi... more Spot blotch (SB) caused by the hemibiotrophic fungal pathogen Cochliobolus sativus is a destructive disease of barley worldwide. To better understand the mechanisms of resistance to this disease, the involvements of salicylic acid (SA), hydrogen peroxide (H 2 O 2) and ion fluxes during the interaction between resistant and susceptible barley seedlings and C. sativus were investigated. Early SA accumulation in leaf tissues was accompanied with an increase in H 2 O 2 concentration in both compatible and incompatible interactions. The resistant cultivar constitutively contained higher levels of H 2 O 2 and SA, as well as during the 72 h as compared with the un-infected control (0 h). However, levels increased rapidly upon infection in both cultivars. Moreover, a markedly greater increase in ion fluxes from the compatible material compared with the incompatible one was observed. Results suggest that SA and H 2 O 2 accumulation are important during both compatible and incompatible barley-C. sativus interactions.
Cereal Research Communications
Scald (Rhynchosporium secalis; Rs) and spot blotch (Cochliobolus sativus; Cs) are important disea... more Scald (Rhynchosporium secalis; Rs) and spot blotch (Cochliobolus sativus; Cs) are important diseases of barley (Hordeum vulgare L.) worldwide. Similar mechanisms and gene transcripts are assumed to be involved in the barley defense response since both these pathogens are necrotrophic fungi. In the current study, the transcriptome in leaves of the same barley genotype WI2291 inoculated with Rs and Cs was compared at different times postinoculation. Comparison of data for barley Rs-and Cs-inoculated plants with mockinoculated plants revealed gene expression changes that included basal defense transcripts and transcripts specific to the establishment of a necrotrophic interaction with associated fungi. During barley-pathogen interaction pathway, WI2291 activated a higher number of genes and pathways in response to Rs infection than in response to Cs invasion. However, families of genes encoding pectin-degrading enzymes, secondary metabolism enzymes, transporters and peptidases are expanded to cover Rs and Cs at an early stage following inoculation. Our results demonstrate differences in the pathways and activated genes of barely cv. WI291challenged by Rs and Cs, and that expression patterns of the same defenseassociated genes were altered in adaptation to different pathogens. Our work provides new insights into the underlying mechanisms related to regulation of different pathways in response to fungal infection.
JOURNAL OF PLANT PATHOLOGY
A total of 75 Erwinia amylovora isolates, collected primarily from fire blighted quince (Cydonia ... more A total of 75 Erwinia amylovora isolates, collected primarily from fire blighted quince (Cydonia oblonga) and pear (Pyrus syriaca and P. communis) shoots, were tested for copper resistance and streptomycin sensitivity. Sixty eight isolates, representing 90.6% of the total were inhibited by 10 μg/ml streptomycin and were thus regarded as streptomycin sensitive. On the contrary, three isolates that were not inhibited by 2000 μg/ml streptomycin were considered as resistant. Fifteen isolates grew well on casitone yeast extract medium in the presence of 1.2 mM copper sulfate and none survived on the same medium containing 2.4 mM copper sulfate, indicating that most of the Syrian E. amylovora isolates are copper tolerant and could cause severe problems even in copper heavily sprayed orchards.. The use of both bactericides in controlling fire blight disease in Syria is discussed.
JOURNAL OF PLANT PATHOLOGY
Thirty Erwinia amylovora strains, collected from the main rosaceous crop-growing regions of Syria... more Thirty Erwinia amylovora strains, collected from the main rosaceous crop-growing regions of Syria, were chosen as representatives of all major pathogenicity groups and were genetically studied by AFLP. Eight primer combinations were utilized and approximately 300 scorable bands in total were generated. Based on similarity coefficient, E. amylovora strains were placed into a main cluster containing two sub-clusters, indicating very low genetic variations among the studied pathogen. The existence of two plasmids, pEA29 (present in nearly all E. amylovora isolates) and pEL60 (present mainly in Lebanese strains), was confirmed using multiplex PCR in all tested Syrian E. amylovora strains, indicating that Lebanese and Syrian isolates may share a common origin.
Under natural conditions, plants are frequently subjected to biotic (i.e., pathogen infection, he... more Under natural conditions, plants are frequently subjected to biotic (i.e., pathogen infection, herbivores, etc..) and abiotic (i.e., low or high temperature, drought and salinity) constraints that cause considerable damage and limit plant productivity worldwide. A wide range of biotic and abiotic stresses results in the accumulation of Reactive Oxygen Species, ROS (H2O2, O2), Nitric Oxide ( NO) and cytosolic calcium ( Ca2+), indicating that plant responses to diseases and drought may operate, at least in part, through common molecular pathways. Additionally, stress-inducible genes have been categorised in two different groups: (a) genes that directly protect against environmental stresses and (b) genes that encode protein kinases. Intriguingly, protein kinases are also involved in disease resistance since many resistance genes (R genes) are in fact kinases. Here, we describe an interactor hunt using the bacterial virulent gene, VirPphA as a bait to screen an Arabidopsis thaliana cDN...
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Papers by Antonious al-Daoude