Expression analysis of NBS resistance gene analogs from chewing cane under two sugarcane diseases stress

Expression analysis of NBS resistance gene anologs（ RGA） from chewing cane under infection of Drechslera sacchari（ Butler） Subram. and Jain and Leptosphaeria sacchari Breda de Haan，respectively，were performed in order to provide theoretical basis for cloning disease resistance genes and studying disease resistance mechanism. seven cloned chewing cane RGAs were considered as 3 gene fragments. The 2 pathogenic bacteria were inoculated into leaves of the susceptible genotype QT 3 and the disease resistant genotype QT 5 using needle puncturing method respectively，all 3 chewing cane RGAs were up-regulated in the initial infection. The response of RGA12478 to the two diseases was the most rapid while the expression of RGA5 was the highest. Especially under the infection of L. sacchari，the expression of RGA12478 at 12h was about 16 and 6 times of RGA5 and RGA36 expression at the same time point respectively. Therefore，RGA5 was considered to be a key disease resistance gene fragment from chewing cane playing a major role in resisting the infection of D. sacchari and L. sacchari in the initial infection stage respectively. To study the overall disease resistance mechanism of RGA5， follow-up research should includ cloning the full-length gene using RACE technology，analysis of gene function and expression level under exogenous signal factor treatments.