Magnaporthe grisea infection modifies expression of anti-oxidant genes in finger millet (Eleusine coracana (L.) Gaertn.)

Abstract

Magnaporthe grisea causes blast disease in finger millet, and has severe economic impact on the crop. Plant defense against fungal pathogens is a complex phenomenon, involving series of reorganizations at morphological and molecular levels. Among these, generation of reactive oxygen species (ROS) is one of the most significant events. The accumulation of ROS in plant cell is regulated by a set of well-known anti-oxidant enzymes. Differential expression of these enzymes at the transcriptional level determines the compatibility of a plant-pathogen interaction. We studied the differential expression of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), class III peroxidase (POX) and lipoxygenase (LOX) in a blast resistant and susceptible genotype at two time points after inoculation [48 h post inoculation (hpi) and 96 hpi] using quantitative PCR. There was an increase in fold expression of SOD between both time points in the resistant genotype and a uniform expression in the susceptible genotype. With regard to APX the resistant genotype showed an increase in expression with time while the susceptible genotype displayed a significant decline in fold expression. Expression of GPX, POX and LOX displayed a descending trend in the resistant genotype and ascending trend in the susceptible one from 48 hpi to 96 hpi.