The unprecedented decline in biodiversity during the past few decades calls for immediate thoroug... more The unprecedented decline in biodiversity during the past few decades calls for immediate thorough review of biological wealth and proper conservation strategies of genetic-diversity. Despite huge economic potential, inadequate characterization of tropical bamboo leads to indiscriminate use of this 'green gold', posing potential threat to the tropical gene pool. Identification of bamboo is difficult due to lack of reproductive structure for its unusually long flowering cycle. This book provides a comprehensive characterization protocol (morphological and molecular) for bamboo species/genotype including development, characterization and screening strategies involving species- and genotype-specific molecular markers. Superiority of bamboo fibers from several natural habitats was assessed as a pilot study and molecular-marker- based screening strategy was described with genomic insights controlling the supremacy. This book should help academicians interested in molecular taxonomy, marker technology and genetic diversity assessment as well as quality-control personnel in paper and pulp industry for selecting superior fiber yielding genotypes with low downstream processing. Link to the book at Amazon: http://www.amazon.com/Tropical-Bamboo-Molecular-Profiling-Diversity/dp/3838374223
Background: Verticillium dahliae (Vd) is a soil-borne vascular pathogen which causes severe wilt ... more Background: Verticillium dahliae (Vd) is a soil-borne vascular pathogen which causes severe wilt symptoms in a wide range of plants. The microsclerotia produced by the pathogen survive in soil for more than 15 years. Results: Here we demonstrate that an exudate preparation induces cytoplasmic calcium elevation in Arabidopsis roots, and the disease development requires the ethylene-activated transcription factor EIN3. Furthermore, the beneficial endophytic fungus Piriformospora indica (Pi) significantly reduced Vd-mediated disease development in Arabidopsis. Pi inhibited the growth of Vd in a dual culture on PDA agar plates and pretreatment of Arabidopsis roots with Pi protected plants from Vd infection. The Pi-pretreated plants grew better after Vd infection and the production of Vd microsclerotia was dramatically reduced, all without activating stress hormones and defense genes in the host. Conclusions: We conclude that Pi is an efficient biocontrol agent that protects Arabidopsis from Vd infection. Our data demonstrate that Vd growth is restricted in the presence of Pi and the additional signals from Pi must participate in the regulation of the immune response against Vd.
Background: Arabidopsis root growth is stimulated by Piriformospora indica, phosphate limitation ... more Background: Arabidopsis root growth is stimulated by Piriformospora indica, phosphate limitation and inactivation of the WRKY6 transcription factor. Combinations of these factors induce unexpected alterations in root and shoot growth, root architecture and root gene expression profiles. Results: The results demonstrate that P. indica promotes phosphate uptake and root development under Pi limitation in wrky6 mutant. This is associated with the stimulation of PHOSPHATE1 expression and ethylene production. Expression profiles from the roots of wrky6 seedlings identified genes involved in hormone metabolism, transport, meristem, cell and plastid proliferation, and growth regulation. 25 miRNAs were also up-regulated in these roots. We generated and discuss here a list of common genes which are regulated in growing roots and which are common to all three growth stimuli investigated in this study.
[Abstract] In this protocol, determination of seed paternity by microsatellite markers in Nicotia... more [Abstract] In this protocol, determination of seed paternity by microsatellite markers in Nicotiana attenuata is described. However, this does not include a protocol for the novel marker selection/identification, but rather exploits the markers generated for a closely related species N.
The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fire... more The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity.
Many plants use sophisticated strategies to maximize their reproductive success via outcrossing. ... more Many plants use sophisticated strategies to maximize their reproductive success via outcrossing. Nicotiana attenuata flowers produce nectar with nicotine at concentrations that are repellent to hummingbirds, increasing the number of flowers visited per plant. In choice tests using native hummingbirds, we show that these important pollinators learn to tolerate high-nicotine nectar but prefer low-nicotine nectar, and show no signs of nicotine addiction. Nectar nicotine concentrations, unlike those of other vegetative tissues, are unpredictably variable among flowers, not only among populations, but also within populations, and even among flowers within an inflorescence. To evaluate whether variations in nectar nicotine concentrations increase outcrossing, polymorphic microsatellite markers, optimized to evaluate paternity in native N. attenuata populations, were used to compare outcrossing in plants silenced for expression of a biosynthetic gene for nicotine production (Napmt1/2) and in control empty vector plants, which were antherectomized and transplanted into native populations. When only exposed to hummingbird pollinators, seeds produced by flowers with nicotine in their nectar had a greater number of genetically different sires, compared to seeds from nicotine-free flowers. As the variation in nectar nicotine levels among flowers in an inflorescence decreased in N. attenuata plants silenced in various combinations of three Dicer-like (DCL) proteins, small RNAs are probably involved in the unpredictable variation in nectar nicotine levels within a plant.
The unprecedented decline in biodiversity during the past few decades calls for immediate thoroug... more The unprecedented decline in biodiversity during the past few decades calls for immediate thorough review of biological wealth and proper conservation strategies of genetic-diversity. Despite huge economic potential, inadequate characterization of tropical bamboo leads to indiscriminate use of this 'green gold', posing potential threat to the tropical gene pool. Identification of bamboo is difficult due to lack of reproductive structure for its unusually long flowering cycle. This book provides a comprehensive characterization protocol (morphological and molecular) for bamboo species/genotype including development, characterization and screening strategies involving species- and genotype-specific molecular markers. Superiority of bamboo fibers from several natural habitats was assessed as a pilot study and molecular-marker- based screening strategy was described with genomic insights controlling the supremacy. This book should help academicians interested in molecular taxonomy, marker technology and genetic diversity assessment as well as quality-control personnel in paper and pulp industry for selecting superior fiber yielding genotypes with low downstream processing. Link to the book at Amazon: http://www.amazon.com/Tropical-Bamboo-Molecular-Profiling-Diversity/dp/3838374223
Background: Verticillium dahliae (Vd) is a soil-borne vascular pathogen which causes severe wilt ... more Background: Verticillium dahliae (Vd) is a soil-borne vascular pathogen which causes severe wilt symptoms in a wide range of plants. The microsclerotia produced by the pathogen survive in soil for more than 15 years. Results: Here we demonstrate that an exudate preparation induces cytoplasmic calcium elevation in Arabidopsis roots, and the disease development requires the ethylene-activated transcription factor EIN3. Furthermore, the beneficial endophytic fungus Piriformospora indica (Pi) significantly reduced Vd-mediated disease development in Arabidopsis. Pi inhibited the growth of Vd in a dual culture on PDA agar plates and pretreatment of Arabidopsis roots with Pi protected plants from Vd infection. The Pi-pretreated plants grew better after Vd infection and the production of Vd microsclerotia was dramatically reduced, all without activating stress hormones and defense genes in the host. Conclusions: We conclude that Pi is an efficient biocontrol agent that protects Arabidopsis from Vd infection. Our data demonstrate that Vd growth is restricted in the presence of Pi and the additional signals from Pi must participate in the regulation of the immune response against Vd.
Background: Arabidopsis root growth is stimulated by Piriformospora indica, phosphate limitation ... more Background: Arabidopsis root growth is stimulated by Piriformospora indica, phosphate limitation and inactivation of the WRKY6 transcription factor. Combinations of these factors induce unexpected alterations in root and shoot growth, root architecture and root gene expression profiles. Results: The results demonstrate that P. indica promotes phosphate uptake and root development under Pi limitation in wrky6 mutant. This is associated with the stimulation of PHOSPHATE1 expression and ethylene production. Expression profiles from the roots of wrky6 seedlings identified genes involved in hormone metabolism, transport, meristem, cell and plastid proliferation, and growth regulation. 25 miRNAs were also up-regulated in these roots. We generated and discuss here a list of common genes which are regulated in growing roots and which are common to all three growth stimuli investigated in this study.
[Abstract] In this protocol, determination of seed paternity by microsatellite markers in Nicotia... more [Abstract] In this protocol, determination of seed paternity by microsatellite markers in Nicotiana attenuata is described. However, this does not include a protocol for the novel marker selection/identification, but rather exploits the markers generated for a closely related species N.
The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fire... more The self-compatible plant Nicotiana attenuata grows in genetically diverse populations after fires, and produces flowers that remain open for 3 days and are visited by assorted pollinators. To determine whether and when post-pollination non-random mate selection occurs among self and non-self pollen, seed paternity and semi-in vivo pollen tube growth were determined in controlled single/mixed pollinations. Despite all pollen sources being equally proficient in siring seeds in single-genotype pollinations, self pollen was consistently selected in mixed pollinations, irrespective of maternal genotype. However, clear patterns of mate discrimination occurred amongst non-self pollen when mixed pollinations were performed soon after corollas open, including selection against hygromycin B resistance (transformation selectable marker) in wild-type styles and for it in transformed styles. However, mate choice among pollen genotypes was completely shut down in plants transformed to be unable to produce (irACO) or perceive (ETR1) ethylene. The post-pollination ethylene burst, which originates primarily from the stigma and upper style, was strongly correlated with mate selection in single and mixed hand-pollinations using eight pollen donors in two maternal ecotypes. The post-pollination ethylene burst was also negatively correlated with the continuation of emission of benzylacetone, the most abundant pollinator-attracting corolla-derived floral volatile. We conclude that ethylene signaling plays a pivotal role in mate choice, and the post-pollination ethylene burst and the termination of benzylacetone release are accurate predictors, both qualitatively and quantitatively, of pre-zygotic mate selection and seed paternity.
Many plants use sophisticated strategies to maximize their reproductive success via outcrossing. ... more Many plants use sophisticated strategies to maximize their reproductive success via outcrossing. Nicotiana attenuata flowers produce nectar with nicotine at concentrations that are repellent to hummingbirds, increasing the number of flowers visited per plant. In choice tests using native hummingbirds, we show that these important pollinators learn to tolerate high-nicotine nectar but prefer low-nicotine nectar, and show no signs of nicotine addiction. Nectar nicotine concentrations, unlike those of other vegetative tissues, are unpredictably variable among flowers, not only among populations, but also within populations, and even among flowers within an inflorescence. To evaluate whether variations in nectar nicotine concentrations increase outcrossing, polymorphic microsatellite markers, optimized to evaluate paternity in native N. attenuata populations, were used to compare outcrossing in plants silenced for expression of a biosynthetic gene for nicotine production (Napmt1/2) and in control empty vector plants, which were antherectomized and transplanted into native populations. When only exposed to hummingbird pollinators, seeds produced by flowers with nicotine in their nectar had a greater number of genetically different sires, compared to seeds from nicotine-free flowers. As the variation in nectar nicotine levels among flowers in an inflorescence decreased in N. attenuata plants silenced in various combinations of three Dicer-like (DCL) proteins, small RNAs are probably involved in the unpredictable variation in nectar nicotine levels within a plant.
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Link to the book at Amazon:
http://www.amazon.com/Tropical-Bamboo-Molecular-Profiling-Diversity/dp/3838374223
wide range of plants. The microsclerotia produced by the pathogen survive in soil for more than 15 years.
Results: Here we demonstrate that an exudate preparation induces cytoplasmic calcium elevation in Arabidopsis
roots, and the disease development requires the ethylene-activated transcription factor EIN3. Furthermore, the
beneficial endophytic fungus Piriformospora indica (Pi) significantly reduced Vd-mediated disease development in
Arabidopsis. Pi inhibited the growth of Vd in a dual culture on PDA agar plates and pretreatment of Arabidopsis
roots with Pi protected plants from Vd infection. The Pi-pretreated plants grew better after Vd infection and the
production of Vd microsclerotia was dramatically reduced, all without activating stress hormones and defense genes
in the host.
Conclusions: We conclude that Pi is an efficient biocontrol agent that protects Arabidopsis from Vd infection.
Our data demonstrate that Vd growth is restricted in the presence of Pi and the additional signals from Pi must
participate in the regulation of the immune response against Vd.
Link to the book at Amazon:
http://www.amazon.com/Tropical-Bamboo-Molecular-Profiling-Diversity/dp/3838374223
wide range of plants. The microsclerotia produced by the pathogen survive in soil for more than 15 years.
Results: Here we demonstrate that an exudate preparation induces cytoplasmic calcium elevation in Arabidopsis
roots, and the disease development requires the ethylene-activated transcription factor EIN3. Furthermore, the
beneficial endophytic fungus Piriformospora indica (Pi) significantly reduced Vd-mediated disease development in
Arabidopsis. Pi inhibited the growth of Vd in a dual culture on PDA agar plates and pretreatment of Arabidopsis
roots with Pi protected plants from Vd infection. The Pi-pretreated plants grew better after Vd infection and the
production of Vd microsclerotia was dramatically reduced, all without activating stress hormones and defense genes
in the host.
Conclusions: We conclude that Pi is an efficient biocontrol agent that protects Arabidopsis from Vd infection.
Our data demonstrate that Vd growth is restricted in the presence of Pi and the additional signals from Pi must
participate in the regulation of the immune response against Vd.