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Ralph A Dean, Center for Integrated Fungal Research, Dept. Plant Pathology, North Carolina State University, Raleigh, NC 27606, USA, presents this Plant and Microbial Seminar on; “Next generation biology: novel insights into fungal pathogenicity.”
Abstract: My research explores the biology of the rice blast fungus Magnaporthe oryzae, the causal agent of rice blast disease. Rice blast is most devastating disease of rice worldwide and is a seminal model to elucidate the basis of pathogen–host interactions. Following the completion of the genome sequence, attention has focused on the transcriptome including non-coding RNA. Though analyses of small RNA, a novel class of small 5′ methylguanosine capped and 3′ polyadenylated RNAs (SCARs) were discovered that primarily map to transcription initiation and termination sites of protein coding genes. SCARs were positively correlated with gene expression, particularly for highly expressed genes including those encoding ribosomal proteins and genes involved in mycelial development. Further analyses of small RNA from infection cells and mycelia revealed evidence for siRNAs. SiRNAs mapping to repetitive elements were highly abundant in mycelia compared to infection cells. These data suggest small RNAs play an active role in regulating fungal growth and development. Whole genome microarray analysis of appressorium formation revealed a core set of differentially genes, which included numerous genes involved in protein turnover and amino acid catabolism. Functional analyses showed that protein catabolism, including endo-proteases and key enzymes involved in shuttling carbon back into the Kreb cycle, is critical for successful host infection. Other research efforts in my laboratory are currently focused on examination of transcriptional networks using protein arrays and protein-protein interactions to define the circuitry regulating the infection process.