Would Combination of Drought QTLs and Rice Xa Genes Be Suitable to Control Bacterial Blight under Climate Change?
C. Sylvestre Gerbert Dossa1, M. Casiana Vera Cruz1, Amelia Henry1, Rolando Torres1, Arvind Kumar1, Ricardo Oliva1, Edgar Maiss2, Kerstin Wydra3
1International Rice Research Institute (IRRI), Philippines
Environmental changes, such as water scarcity and high temperature negatively affect plant growth, production and response to biotic stress. Drought and high temperature in the future will considerably influence rice R gene's response to bacterial blight (BB) caused by Xanthomonas oryza pv. oryzae (Xoo). To understand the outcome of the interaction between rice, drought and bacterial blight, comparative analysis of single and double stress responses by field and greenhouse studies were conducted. Sixteen rice genotypes (drought QTLs, Xa-genes, Xa-gene + drought QTLs and drought/BB susceptible check) were screened under field drought and irrigated conditions with Xoo strains PXO61 and PXO86 (field) and PXO61, PXO86, PXO99 and PXO145 (greenhouse). Our results showed lines with drought QTLs being susceptible to BB under drought and irrigated conditions although disease severity was less in drought treatment compared to irrigated one. Near isogenic lines carrying Xa-genes revealed effective under drought except Xa4 which showed disease increase with PXO61 (avrXa4 strain). Combination of drought QTLs and Xa4 gene revealed more effective compared to drought QTLs genotypes. Our results also showed significant difference between disease severity at 14 and disease severity at 21 days post inoculation.
Keywords: Bacterial blight, climate changes, drought QTLs, rice, Xa-genes
Contact Address: Kerstin Wydra, Erfurt University of Applied Sciences, Horticulture - Plant Production and Climate Change, Leipziger Str. 77, 99085 Erfurt, Germany, e-mail: kerstin.wydrafh-erfurt.de