Identification of defense-related genes in sorghum responding to the challenge by Colletotrichum sublineolum

Abstract

Sorghum is one of the five top cereal crops in the world. It is an annual grass that is extremely drought tolerant, making it an excellent choice for arid and dry areas. Colletotriclum sublineolum, one of the more important genera of plant pathogenic fungi, causes anthracnose in sorghum, affecting leaves, stems, peduncles, panicles and grains, either separately or all together. Sorghum anthracnose, one of the most important sorghum diseases, limits grain production in most growing regions around the world. Suppression subtractive hybridization was used to identify sorghum genes induced in defense response. Two cDNA libraries enriched for transcripts differentially expressed in C. sublineolum -infected and uninfected sorghum (cultivar DK18, which is resistant to C. sublineolum) were generated. After differentially screening by membrane-based hybridization and subsequent confirmation by reverse northern blot analysis, selected clones were sequenced and analyzed. Seventy-five unique cDNA clones were obtained and assigned into fourteen different groups according to the putative functions of their homologous genes in the database. Most of these clones were not previously classified as being induced in response to pathogens. Further analysis and characterisation will be discussed.