AGRIS record. Record number, US1999002875. Titles, Biotechnology and the environment: challenges ... more AGRIS record. Record number, US1999002875. Titles, Biotechnology and the environment: challenges and opportunities. Personal Authors, Vickers, KM (University of California, Berkeley, CA.),Lemaux, PG. Publication Date, (Jul 1998). AGRIS Subj. Cat. ...
The ecology of fungi lags behind that of plants and animals because most fungi are microscopic an... more The ecology of fungi lags behind that of plants and animals because most fungi are microscopic and hidden in their substrates. Here, we address the basic ecological process of fungal succession in nature using the microscopic, arbuscular mycorrhizal fungi (AMF) that form essential mutualisms with 70-90% of plants. We find a signal for temporal change in AMF community similarity that is 40-fold stronger than seen in the most recent studies, likely due to weekly samplings of roots, rhizosphere and soil throughout the 17 weeks from seedling to fruit maturity and the use of the fungal DNA barcode to recognize species in a simple, agricultural environment. We demonstrate the patterns of nestedness and turnover and the microbial equivalents of the processes of immigration and extinction, that is, appearance and disappearance. We also provide the first evidence that AMF species co-exist rather than simply co-occur by demonstrating negative, density-dependent population growth for multiple ...
Proceedings of the National Academy of Sciences of the United States of America, May 16, 2018
Drought stress is a major obstacle to crop productivity, and the severity and frequency of drough... more Drought stress is a major obstacle to crop productivity, and the severity and frequency of drought are expected to increase in the coming century. Certain root-associated bacteria have been shown to mitigate the negative effects of drought stress on plant growth, and manipulation of the crop microbiome is an emerging strategy for overcoming drought stress in agricultural systems, yet the effect of drought on the development of the root microbiome is poorly understood. Through 16S rRNA amplicon and metatranscriptome sequencing, as well as root metabolomics, we demonstrate that drought delays the development of the early sorghum root microbiome and causes increased abundance and activity of monoderm bacteria, which lack an outer cell membrane and contain thick cell walls. Our data suggest that altered plant metabolism and increased activity of bacterial ATP-binding cassette (ABC) transporter genes are correlated with these shifts in community composition. Finally, inoculation experime...
Evidence shows that decreasing the light-harvesting antenna size of the photosystems in tobacco h... more Evidence shows that decreasing the light-harvesting antenna size of the photosystems in tobacco helps to increase the photosynthetic productivity and plant canopy biomass accumulation under high-density cultivation conditions. Decreasing, or truncating, the chlorophyll antenna size of the photosystems can theoretically improve photosynthetic solar energy conversion efficiency and productivity in mass cultures of algae or plants by up to threefold. A Truncated Light-harvesting chlorophyll Antenna size (TLA), in all classes of photosynthetic organisms, would help to alleviate excess absorption of sunlight and the ensuing wasteful non-photochemical dissipation of excitation energy. Thus, solar-to-biomass energy conversion efficiency and photosynthetic productivity in high-density cultures can be increased. Applicability of the TLA concept was previously shown in green microalgae and cyanobacteria, but it has not yet been demonstrated in crop plants. In this work, the TLA concept was applied in high-density tobacco canopies. The work showed a 25% improvement in stem and leaf biomass accumulation for the TLA tobacco canopies over that measured with their wild-type counterparts grown under the same ambient conditions. Distinct canopy appearance differences are described between the TLA and wild type tobacco plants. Findings are discussed in terms of concept application to crop plants, leading to significant improvements in agronomy, agricultural productivity, and application of photosynthesis for the generation of commodity products in crop leaves.
The production and marketing of horticultural crops is undergoing continuous change globally. Thi... more The production and marketing of horticultural crops is undergoing continuous change globally. This is due to the growing demands of consumers for safe and healthy foods, increased urbanisation of societies, the growth in scale and influence of supermarkets, the corporatisation of farming, changes in the availability of labour and the low priority given to food production by governments. Horticultural science can respond to many of these challenges through research and innovation that can seek to gain more efficient methods of crop production, refined post-harvest storage and handling methods, newer and higher value cultivars, demonstration of health benefits, and newer methods of knowledge dissemination.
Proceedings of the National Academy of Sciences of the United States of America, Jul 18, 2017
Barley is the cornerstone of the malting and brewing industry. It is known that 250 quantitative ... more Barley is the cornerstone of the malting and brewing industry. It is known that 250 quantitative trait loci (QTLs) of the grain are associated with 19 malting-quality phenotypes. However, only a few of the contributing genetic components have been identified. One of these, on chromosome 4H, contains a major malting QTL, QTL2, located near the telomeric region that accounts, respectively, for 28.9% and 37.6% of the variation in the β-glucan and extract fractions of malt. In the current study, we dissected the QTL2 region using an expression- and microsynteny-based approach. From a set of 22 expressed sequence tags expressed in seeds at the malting stage, we identified a candidate gene, TLP8 (thaumatin-like protein 8), which was differentially expressed and influenced malting quality. Transcript abundance and protein profiles of TLP8 were studied in different malt and feed varieties using quantitative PCR, immunoblotting, and enzyme-linked immunosorbent assay (ELISA). The experiments ...
Plant transformation has enabled fundamental insights into plant biology and revolutionized comme... more Plant transformation has enabled fundamental insights into plant biology and revolutionized commercial agriculture. Unfortunately, for most crops, transformation and regeneration remain arduous even after more than thirty years of technological advances. Genome editing provides new opportunities to enhance crop productivity, but relies on genetic transformation and plant regeneration, which are bottlenecks in the process. Herein we review the state of plant transformation and point to innovations needed to enable genome editing in crops. Plant tissue culture methods need optimization and simplification for efficiency and minimize time in culture. Currently, specialized facilities exist for crop transformation. Single cell and robotic techniques should be developed for high throughput genomic screens. Utilization of plant genes involved in developmental reprogramming, wound response, and/or homologous recombination could boost recovery of transformed plants. Engineering universal Agr...
Recent results reveal that high frequencies of cytogenetic abnormalities occur in transgenic barl... more Recent results reveal that high frequencies of cytogenetic abnormalities occur in transgenic barley, oat and orchardgrass plants generated from either immature embryos or highly regenerative, green tissues via microprojectile bombardment, compared with nontransgenic plants: ...
AGRIS record. Record number, US1999002875. Titles, Biotechnology and the environment: challenges ... more AGRIS record. Record number, US1999002875. Titles, Biotechnology and the environment: challenges and opportunities. Personal Authors, Vickers, KM (University of California, Berkeley, CA.),Lemaux, PG. Publication Date, (Jul 1998). AGRIS Subj. Cat. ...
The ecology of fungi lags behind that of plants and animals because most fungi are microscopic an... more The ecology of fungi lags behind that of plants and animals because most fungi are microscopic and hidden in their substrates. Here, we address the basic ecological process of fungal succession in nature using the microscopic, arbuscular mycorrhizal fungi (AMF) that form essential mutualisms with 70-90% of plants. We find a signal for temporal change in AMF community similarity that is 40-fold stronger than seen in the most recent studies, likely due to weekly samplings of roots, rhizosphere and soil throughout the 17 weeks from seedling to fruit maturity and the use of the fungal DNA barcode to recognize species in a simple, agricultural environment. We demonstrate the patterns of nestedness and turnover and the microbial equivalents of the processes of immigration and extinction, that is, appearance and disappearance. We also provide the first evidence that AMF species co-exist rather than simply co-occur by demonstrating negative, density-dependent population growth for multiple ...
Proceedings of the National Academy of Sciences of the United States of America, May 16, 2018
Drought stress is a major obstacle to crop productivity, and the severity and frequency of drough... more Drought stress is a major obstacle to crop productivity, and the severity and frequency of drought are expected to increase in the coming century. Certain root-associated bacteria have been shown to mitigate the negative effects of drought stress on plant growth, and manipulation of the crop microbiome is an emerging strategy for overcoming drought stress in agricultural systems, yet the effect of drought on the development of the root microbiome is poorly understood. Through 16S rRNA amplicon and metatranscriptome sequencing, as well as root metabolomics, we demonstrate that drought delays the development of the early sorghum root microbiome and causes increased abundance and activity of monoderm bacteria, which lack an outer cell membrane and contain thick cell walls. Our data suggest that altered plant metabolism and increased activity of bacterial ATP-binding cassette (ABC) transporter genes are correlated with these shifts in community composition. Finally, inoculation experime...
Evidence shows that decreasing the light-harvesting antenna size of the photosystems in tobacco h... more Evidence shows that decreasing the light-harvesting antenna size of the photosystems in tobacco helps to increase the photosynthetic productivity and plant canopy biomass accumulation under high-density cultivation conditions. Decreasing, or truncating, the chlorophyll antenna size of the photosystems can theoretically improve photosynthetic solar energy conversion efficiency and productivity in mass cultures of algae or plants by up to threefold. A Truncated Light-harvesting chlorophyll Antenna size (TLA), in all classes of photosynthetic organisms, would help to alleviate excess absorption of sunlight and the ensuing wasteful non-photochemical dissipation of excitation energy. Thus, solar-to-biomass energy conversion efficiency and photosynthetic productivity in high-density cultures can be increased. Applicability of the TLA concept was previously shown in green microalgae and cyanobacteria, but it has not yet been demonstrated in crop plants. In this work, the TLA concept was applied in high-density tobacco canopies. The work showed a 25% improvement in stem and leaf biomass accumulation for the TLA tobacco canopies over that measured with their wild-type counterparts grown under the same ambient conditions. Distinct canopy appearance differences are described between the TLA and wild type tobacco plants. Findings are discussed in terms of concept application to crop plants, leading to significant improvements in agronomy, agricultural productivity, and application of photosynthesis for the generation of commodity products in crop leaves.
The production and marketing of horticultural crops is undergoing continuous change globally. Thi... more The production and marketing of horticultural crops is undergoing continuous change globally. This is due to the growing demands of consumers for safe and healthy foods, increased urbanisation of societies, the growth in scale and influence of supermarkets, the corporatisation of farming, changes in the availability of labour and the low priority given to food production by governments. Horticultural science can respond to many of these challenges through research and innovation that can seek to gain more efficient methods of crop production, refined post-harvest storage and handling methods, newer and higher value cultivars, demonstration of health benefits, and newer methods of knowledge dissemination.
Proceedings of the National Academy of Sciences of the United States of America, Jul 18, 2017
Barley is the cornerstone of the malting and brewing industry. It is known that 250 quantitative ... more Barley is the cornerstone of the malting and brewing industry. It is known that 250 quantitative trait loci (QTLs) of the grain are associated with 19 malting-quality phenotypes. However, only a few of the contributing genetic components have been identified. One of these, on chromosome 4H, contains a major malting QTL, QTL2, located near the telomeric region that accounts, respectively, for 28.9% and 37.6% of the variation in the β-glucan and extract fractions of malt. In the current study, we dissected the QTL2 region using an expression- and microsynteny-based approach. From a set of 22 expressed sequence tags expressed in seeds at the malting stage, we identified a candidate gene, TLP8 (thaumatin-like protein 8), which was differentially expressed and influenced malting quality. Transcript abundance and protein profiles of TLP8 were studied in different malt and feed varieties using quantitative PCR, immunoblotting, and enzyme-linked immunosorbent assay (ELISA). The experiments ...
Plant transformation has enabled fundamental insights into plant biology and revolutionized comme... more Plant transformation has enabled fundamental insights into plant biology and revolutionized commercial agriculture. Unfortunately, for most crops, transformation and regeneration remain arduous even after more than thirty years of technological advances. Genome editing provides new opportunities to enhance crop productivity, but relies on genetic transformation and plant regeneration, which are bottlenecks in the process. Herein we review the state of plant transformation and point to innovations needed to enable genome editing in crops. Plant tissue culture methods need optimization and simplification for efficiency and minimize time in culture. Currently, specialized facilities exist for crop transformation. Single cell and robotic techniques should be developed for high throughput genomic screens. Utilization of plant genes involved in developmental reprogramming, wound response, and/or homologous recombination could boost recovery of transformed plants. Engineering universal Agr...
Recent results reveal that high frequencies of cytogenetic abnormalities occur in transgenic barl... more Recent results reveal that high frequencies of cytogenetic abnormalities occur in transgenic barley, oat and orchardgrass plants generated from either immature embryos or highly regenerative, green tissues via microprojectile bombardment, compared with nontransgenic plants: ...
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Papers by Peggy Lemaux