Identification of genes differentially expressed in maize (Zea mays L.) during Rhizoctonia Solani Kühn infection by suppression subtractive hybridization

Abstract

Banded leaf and sheath blight (BLSB) caused by Rhizoctonia solani Kuhn is an emerging problem in maize worldwide. To study gene expression in maize plants infected by R. solani Kuhn, we constructed two suppression subtractive hybridization (SSH) library using complementary DNA (cDNA) from uninoculated plants as a driver and those from inoculated plants as a tester. After two cycles of hybridization, 84 cDNA clones from the forward and reverse SSH library were obtained and sequenced. Gene analysis indicated that these clones represented 51 single genes, and the functions of 35 genes could be assigned using existing databases. Thirty-five expression sequences tags (ESTs) were classified in fuctional categories, such as: transcription, regulation, protein processing, metabolism, defense, disease response and other functions. The expression of 15 genes was analyzed by semi-quantitative reverse-transcription-polymerase chain reaction (RT-PCR) and found to be up-regulated or down-regulated in response to R. solani Kuhn re-infection. In conclusion, this study provides a basis for a molecular understanding of host reaction in response to pathogen. Key words: Banded leaf and sheath blight, expressed sequence tag, gene expression, maize, suppression subtractive hybridization.