ldentication of Early Stress – induced Genes from Rice lnfected with Rice Blast Pathogen (Pyricularia grisea (Cook) Sacc.)

Abstract

is a devastating fungal pathogen of rice that severely causes a reduction of grain yield in certain regions of Thailand. To elucidate the fungal-plant interaction   during  pathosystem   in  order  to  identify genes associated    with  early  stages  of  rice  infection, cDNA  libraries  were   constructed    from 3-week  old  rice   seedling (lndica   cultivar Hahng-Yi 71, a  resistant  variety) at 6 and 24 hours  after  artificial  inoculation  with   fungal   spores  at  the concentration  of 1x 10⁶ spores  per  ml.  The experiments were  conducted   at  the   Plant   Protection  Research  and  Development   Office  and  the  Biotechnology  Research  and Development   Office, Department  of  Agriculture   during October 2500 to   September   2007. From  resistant  libraries, named  OSHy71/EST6  and  OSHy71/EST24  obtained  from Hahng Yi-71, a total  of  sixty  cDNA  clones  of   each library are randomly chosen  and  used  to  estimate  the  average insert size  of  the  cDNA  clones  which  are  approximately 2.5-kb and  1.5-kb in  size,  respectively. To identify candidate  genes associated  with   disease  resistance,  twenty-five  ESTs (from  OSHy71/EST24) had  been  further  single-passed sequenced  and   compared   with  GenBank database.  The putative functional classification  of  these  twenty-five genes display   the   majority   of  them are associated with hypothetical proteins, ligand binder/carrier functions (Ulp 1 protease-like protein, glycosylphos phatidylinositol anchor attachment 1-like protein, cytochrome P450 monooxygenase), transcription factor (NAC 2, NAM-like protein, enamelin), retrotransposon (Retrosat 1/ retrotransposon and Ty 3 Gypsy-type Retrosat 2 retrotransposon), and importantly previously reported disease resistant genes NBS-LRR resistance gene (RGH 1) and RPM 1 in rice.