Phytophthora infestans associated global gene expression profile in a late blight resistant Indian potato cv. Kufri Girdhari

From the past late blight is one of the most dreaded diseases of potato worldwide. In this study, microarray-based gene expression was analysed in a late blight resistant Indian potato cultivar Kufri Girdhari upon Phytophthora infestans infection. A comprehensive transcriptional analysis was performed using cDNA microarrays, containing 70,083 ESTs (expressed sequence tag libraries) from plant leaf tissues collected at two stages: pre-inoculation (0 h, water spray as control) and post-inoculation (72 h after inoculation) by challenge inoculation of P. infestans. Microarray analysis using scatter plot revealed out of total statistically significant (P≤0.01) genes (#4622), a total of 2,344 resistance genes were up-regulated at post-inoculation stage compared to pre-inoculation. These significantly genes (#2,344) were greatly expressed at post-inoculation and contribute resistance in response to the challenge inoculation of P. infestans. Further, hierarchical clustering classified the genes (#2,344) expressions into 8 different clusters. Study revealed that molecular chaperones were found to be mainly controlling resistance mechanism in Kufri Girdhari and acted as downstream signalling pathway for defense related genes response to various mechanisms (stress/harmone/signalling genes/transporter/metabolism). The selected highly up-regulated genes were further validated for their expression in the cultivar by real-time (RT) PCR analysis. Thus study provides many candidate genes/transcripts for future characterization and functionality assay as initial starting point for research work.