Transcriptome-wide identification and transcriptional profiling reveal remarkable expression modulation of redox genes in Zingiber zerumbet against Pythium myriotylum

Abstract

Using a transcriptome-based bioinformatics approach coupled with custom gene expression microarray we studied the expression of redox genes in a resistant accession of Zingiber zerumbet (L.) in response to the oomycete pathogen Pythium myriotylum Drechsler. Expression of 97 genes comprising of 11 RBOHs, two CATs, three AOXs, four SODs, five APXs, two FERs, three PrxRs, five GPXs, eight GSTs, 15 GRXs, 16 POXs, and 23 TRXs was examined at 18 h, 36 h and 48 h post-inoculation with P. myriotylum. Microarray data revealed significant (p ≤ 0.05) modulation of 41 genes belonging to 10 gene families. The RT-qPCR analysis and enzyme activity assays of selected redox candidates corroborated the microarray data. The genes encoding extracellular ROS generators RBOHD, RBOHB and POX57 were significantly induced. Among the ROS scavengers, while the gene encoding chloroplast localized Cu–Zn SOD and peroxisomal CAT2 were significantly upregulated, the gene producing chloroplast localized APX6 and APXT and mitochondrial AOX1a and AOX1b were significantly declined. Similarly, the expression of certain members belonging to the cellular redox regulators GST, GRX, and TRX were also modulated. The results highlight the involvement of a large-scale transcriptional reprogramming of redox machinery in Z. zerumbet in mounting host defence against P. myriotylum.