Yong Hoon Lee
Chonbuk National University, Republic of Korea
Title: Differences of genomic and phenomic responses in resistant and susceptible rice varieties to bacterial leaf blight
Biography
Biography: Yong Hoon Lee
Abstract
Bacterial leaf blight (BLB) causes severe yield losses in temperate and tropical rice-growing regions. To reduce the occurrence of BLB, disease resistant rice cultivars are developed by introducing resistant genes. In this study, near-isogenic rice genotypes, IRBB21and IR24, which are resistant and susceptible to BLB, respectively were challenge inoculated with Xanthomonas oryzae pv. oryzae (Xoo) races, K1, K2, and K3 by scissor clip method. IR24 was susceptible to all the inoculated Xoo races (S interaction), but IRBB21was highly resistant to K2 and K3 (R interaction), and moderately resistant to K1 race (MR interaction). The influence on photosynthesis in the various combinations was measured using Chlorophyll Fluorometer. The Fv/Fm was significantly decreased in leaves of S and MR interaction. However, there was no drastic fluctuation in the leaves of R interaction. The effective PSII quantum yield (ΦPSII) value decreased severely in S interaction, but slightly in R interaction at 2 days after inoculation (dai) before symptoms were developed. ΦPSII value in S interaction significantly decreased till 7 dai, while an increase was observed in R interaction. To better understand the difference in response of R and S interactions, we investigated the expression levels of defense-related genes. The expression of OsPR1a, OsPR1b, and OsPR10a significantly increased in S interaction at 2 dai and then downregulated at 5 dai. The expression of the genes in R interaction increased significantly from 2 to 5 dai. Furthermore, we obtained hyperspectral images from the Xoo inoculated rice leaves and analyzed by principal component analysis. The difference in the images between resistant and susceptible variety was observed from 2 dai, which would help us to screen resistant crops in early stage of infection. The underlying proteomic and metabolomic differences need to be further explored.