Mandy Hsia | Cal State LA (original) (raw)
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Brachypodium distachyon has been widely adopted as a pathosystem for study of cereal pathogens. F... more Brachypodium distachyon has been widely adopted as a pathosystem for study of cereal pathogens. Fusarium crown rot (FCR), primarily caused by the necrotrophic fungal pathogen Fusarium pseudograminearum, constitutes a major disease risk for the Australian wheat industry. The aim of this work was to assess whether species in the genus Brachypodium will be a useful model for characterizing the molecular basis for resistance to F. pseudograminearum. Two Brachypodium species were found to be readily infected by F. pseudograminearum producing similar symptoms and disease progression to that observed in wheat and barley. A large number of Turkish natural accessions were screened for FCR susceptibility and several ecotypes were found to differ significantly in disease severity. Brachypodium hybridium accessions exhibited significantly greater quantitative resistance compared with B. distachyon accessions. RNAseq was utilized to observe the host molecular response during FCR infection in whe...
ABSTRACT Difficulties in understanding the molecular basis of resistance to necrotrophic pathogen... more ABSTRACT Difficulties in understanding the molecular basis of resistance to necrotrophic pathogens of cereals arise from the highly quantitative nature of resistance, further compounded by host genomic complexity. The aim of this project is to develop Brachypodium distachyon, the genetic model for Pooid grasses, as a pathosystem to study the host molecular response during infection by Fusarium pseudograminearum (Fp), the predominant cause of Fusarium crown rot, costing the Australian wheat industry A$79 million/annum. A transcriptomic approach using RNAseq (Illumina HiSeq2000) was adopted to comparatively analyse global gene expression in wheat and Brachypodium seedlings three days after inoculation with Fp. Four biological replicates of two treatments (Fp and mock-inoculated), each consisting of 16 and 32 plants for wheat and Brachypodium respectively, were sequenced and differential gene expression was assessed using the Tuxedo Suite bioinformatics package. Approximately 10% of annotated canonical transcripts showed differential expression in both species with 2234 wheat genes (1521 up- and 713 down-regulated) and 2292 Brachypodium genes (1316 up- and 976 down-regulated) differentially expressed during infection. Shared responses activated during pathogen challenge include expression of defence proteins, production of phytoalexins, mycotoxin detoxification and systemic defence signalling pathway activation. Comparative analysis of wheat and Brachypodium transcriptomes reveal close functional overlap between the gene sets and reveal a high degree of sequence identity for homologous of differentially expressed genes between species, highlighting the suitability of Brachypodium as a model for this system. Further work will exploit established transformational and mutant resources to characterize Brachypodium genes of interest emerging from this study.
ABSTRACT. In model plants, strong resistance to necrotrophic pathogens has been achieved via inac... more ABSTRACT. In model plants, strong resistance to necrotrophic pathogens has been achieved via inactivation of host susceptibility genes. We are exploring the inactivation of susceptibility genes as a strategy to achieve novel resistance to crown rot. Initially, six candidate genes were selected from research in model plants, and wheat lines lacking these genes were identified within a mutant population. Furthermore, to attempt to overcome functional redundancy in hexaploid wheat, a crossing strategy was used to combine ...
Journal of Biological Chemistry, 2010
Annals of botany, 2015
Cereal diseases cause tens of billions of dollars of losses annually and have devastating humanit... more Cereal diseases cause tens of billions of dollars of losses annually and have devastating humanitarian consequences in the developing world. Increased understanding of the molecular basis of cereal host-pathogen interactions should facilitate development of novel resistance strategies. However, achieving this in most cereals can be challenging due to large and complex genomes, long generation times and large plant size, as well as quarantine and intellectual property issues that may constrain the development and use of community resources. Brachypodium distachyon (brachypodium) with its small, diploid and sequenced genome, short generation time, high transformability and rapidly expanding community resources is emerging as a tractable cereal model. Recent research reviewed here has demonstrated that brachypodium is either susceptible or partially susceptible to many of the major cereal pathogens. Thus, the study of brachypodium-pathogen interactions appears to hold great potential t...
Brachypodium distachyon has been widely adopted as a pathosystem for study of cereal pathogens. F... more Brachypodium distachyon has been widely adopted as a pathosystem for study of cereal pathogens. Fusarium crown rot (FCR), primarily caused by the necrotrophic fungal pathogen Fusarium pseudograminearum, constitutes a major disease risk for the Australian wheat industry. The aim of this work was to assess whether species in the genus Brachypodium will be a useful model for characterizing the molecular basis for resistance to F. pseudograminearum. Two Brachypodium species were found to be readily infected by F. pseudograminearum producing similar symptoms and disease progression to that observed in wheat and barley. A large number of Turkish natural accessions were screened for FCR susceptibility and several ecotypes were found to differ significantly in disease severity. Brachypodium hybridium accessions exhibited significantly greater quantitative resistance compared with B. distachyon accessions. RNAseq was utilized to observe the host molecular response during FCR infection in whe...
ABSTRACT Difficulties in understanding the molecular basis of resistance to necrotrophic pathogen... more ABSTRACT Difficulties in understanding the molecular basis of resistance to necrotrophic pathogens of cereals arise from the highly quantitative nature of resistance, further compounded by host genomic complexity. The aim of this project is to develop Brachypodium distachyon, the genetic model for Pooid grasses, as a pathosystem to study the host molecular response during infection by Fusarium pseudograminearum (Fp), the predominant cause of Fusarium crown rot, costing the Australian wheat industry A$79 million/annum. A transcriptomic approach using RNAseq (Illumina HiSeq2000) was adopted to comparatively analyse global gene expression in wheat and Brachypodium seedlings three days after inoculation with Fp. Four biological replicates of two treatments (Fp and mock-inoculated), each consisting of 16 and 32 plants for wheat and Brachypodium respectively, were sequenced and differential gene expression was assessed using the Tuxedo Suite bioinformatics package. Approximately 10% of annotated canonical transcripts showed differential expression in both species with 2234 wheat genes (1521 up- and 713 down-regulated) and 2292 Brachypodium genes (1316 up- and 976 down-regulated) differentially expressed during infection. Shared responses activated during pathogen challenge include expression of defence proteins, production of phytoalexins, mycotoxin detoxification and systemic defence signalling pathway activation. Comparative analysis of wheat and Brachypodium transcriptomes reveal close functional overlap between the gene sets and reveal a high degree of sequence identity for homologous of differentially expressed genes between species, highlighting the suitability of Brachypodium as a model for this system. Further work will exploit established transformational and mutant resources to characterize Brachypodium genes of interest emerging from this study.
ABSTRACT. In model plants, strong resistance to necrotrophic pathogens has been achieved via inac... more ABSTRACT. In model plants, strong resistance to necrotrophic pathogens has been achieved via inactivation of host susceptibility genes. We are exploring the inactivation of susceptibility genes as a strategy to achieve novel resistance to crown rot. Initially, six candidate genes were selected from research in model plants, and wheat lines lacking these genes were identified within a mutant population. Furthermore, to attempt to overcome functional redundancy in hexaploid wheat, a crossing strategy was used to combine ...
Journal of Biological Chemistry, 2010
Annals of botany, 2015
Cereal diseases cause tens of billions of dollars of losses annually and have devastating humanit... more Cereal diseases cause tens of billions of dollars of losses annually and have devastating humanitarian consequences in the developing world. Increased understanding of the molecular basis of cereal host-pathogen interactions should facilitate development of novel resistance strategies. However, achieving this in most cereals can be challenging due to large and complex genomes, long generation times and large plant size, as well as quarantine and intellectual property issues that may constrain the development and use of community resources. Brachypodium distachyon (brachypodium) with its small, diploid and sequenced genome, short generation time, high transformability and rapidly expanding community resources is emerging as a tractable cereal model. Recent research reviewed here has demonstrated that brachypodium is either susceptible or partially susceptible to many of the major cereal pathogens. Thus, the study of brachypodium-pathogen interactions appears to hold great potential t...