Microarray-based transcriptome analysis of the grass-endophyte association

FELITTI, S.A.; TIAN, P.; CHAPMAN, R.; ERWIN, T.; EDWARDS, D.; SPANGENBERG, G.C.

Adelaide, Australia

Congreso; 8th International Congress of Plant Molecular Biology; 2006

Sally Jay Conferences

Neotyphodium lolii, N. coenophialum and Epichloë festucae are common symbiotic fungal endophytes of the temperate pasture grasses perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea) and red fescue (Festuca rubra), respectively. No comprehensive genomic resource for Neotyphodium and Epichloë species has been generated until recently (http://hornbill.cspp.latrobe.edu.au/). The availability of expressed sequence tags (ESTs) corresponding to partially sequenced endophyte cDNA clones enables the construction of endophyte-specific microarrays. A genomic resource of 13,964 ESTs representing 7,585 unique genes has been established for Neotyphodium and Epichloë fungal endophytes. Two spotted cDNA-based microarrays have been generated, permitting the interrogation of 3,806 Neotyphodium genes (NchipTM microarray) and 4,195 Neotyphodium and 920 Epichloë genes (EndoChipTM microarray), respectively. The microarrays provide a tool for high-throughput endophyte transcriptomic analysis, including genome-specific gene expression studies, profiling of novel endophyte genes, and investigation of the host grass-symbiont interaction.  Comparative transcriptomic analysis was performed for different conditions of saprophytic growth, different asexual endophyte taxa (N. coenophialum and N. lolii) in liquid culture, different asexual and sexual endophyte taxa, and unmodified compared to transgene-containing asexual endophytes. The endophyte microarrays were also applied to detailed analysis of in planta gene expression using endophyte-infected and uninfected ryegrass plants in isogenic host genetic background. Conparative transcriptomic analysis was performed for different endophyte isolates and for different ryegrass organs using the EndoChipTM and the 15K Ryegrass unigene microarrays. Northern hybridisation analysis provided data for the validation of microarray-based gene expression studies.