Two Rice Major Xa Genes: Xa4 and Xa7 Showed Complementary Effects to Combined Stresses of Bacterial Blight and High Temperature
C. Sylvestre Gerbert Dossa1, Kerstin Wydra2, Johnny Balidion1, Ricardo Oliva1, Edgar Maiss3, M. Casiana Vera Cruz1
1International Rice Research Institute (IRRI), Plant Breeding, Genetics and Biotechnology, Philippines
Ambient temperature is predicted to increase, and global warming with amplitude of heat episodes affects different physiological processes in crops. Rice is one of the most important cereal crops used as model crops for genomics and genetics studies. Although elevated temperature influences resistance (R) genes, the effect of heat on rice Xa-gene mediated resistance to Xanthomonas oryzae pv. oryzae (Xoo) remains to be elucidated. In this study, in IR24 near-isogenic-lines, IRBB4 (IR24+Xa4), IRBB7 (IR24+Xa7), and IRBB67 (IR24 +Xa4+Xa7) complementary effects of Xa4 on Xa7 in pyramided line IRBB67 were shown, and less effectiveness of single Xa4 gene to bacterial blight when ambient temperature increased from 29/21°C (day/night temperatures) to 35/31°C. The bacterial spread was limited in IRBB7 at high temperature, but no differences were observed between IR24 (no effective R gene) and IRBB4.
Keywords: Bacterial blight, High temperature, rice, Xa4, Xa7
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