Global Approaches to Identify Genes Involved during Infection Structure Formation in Rice Blast Fungus,Magnaporthe grisea

Choi, Woo Bong

The Plant Pathology Journal 2003;19(1):34-42.
Published online February 28, 2003.

Global Approaches to Identify Genes Involved during Infection Structure Formation in Rice Blast Fungus,Magnaporthe grisea

Woo Bong Choi

Abstract

The ascomycete Magnaporthe grisea is a pathogen of rice blast and is known to form specialized infection structures called appressoria for successful infection into host cells. To understand the molecular mechanism underlying infection process, appressorium-related genes were identified through global approaches including EST sequencing, differential hybridization, and suppression subtractive hybridization. EST database was generated on >2,000 cDNA clones randomly selected from appressorium stage cDNA library. Large number of ESTs showed homology to known proteins possibly involved in infection-related cellular development (attachment, germination, appressorium formation, and colonization) of rice blast fungus. The 1051 ESTs showing significant homology to known genes were assigned to 11 functional categories. Differential hybridization and suppression subtractive hybridization were applied to identify genes showing an appressorium stage specific expression pattern. A number of genes were selected as up-regulated during appressorium formation compared with the vegetative growing stage. Clones from various cDNA libraries constructed in different developmental stages were arrayed on slide glass for further expression profiling study. Functional characterization of genes identified from these global approaches may lead to a better understanding of the infection process of this devastating plant disease, and the development of novel ways to protect host plant.

Key Words: appressorium, differential hybridization, EST, rice blast fungus, suppression subtractive hybridization