Institute of Agrobiological Sciences, NARO (NIAS), Tsukuba, Japan.
RIKEN Yokohama, Tsurumi, Yokohama, Japan.
Sci Rep. 2019 Jan 24;9(1):587. doi: 10.1038/s41598-018-37365-1.
The fungal pathogen Rhizoctonia solani causes devastating diseases in hundreds of plant species. Among these, R. solani causes sheath blight, one of the three major diseases in rice. To date, few genes have been reported that confer resistance to R. solani. Here, rice-FOX Arabidopsis lines identified as having resistance to a bacterial pathogen, Pseudomonas syringae pv. tomato DC3000, and a fungal pathogen, Colletotrichum higginsianum were screened for disease resistance to R. solani. BROAD-SPECTRUM RESISTANCE2 (BSR2), a gene encoding an uncharacterized cytochrome P450 protein belonging to the CYP78A family, conferred resistance to R. solani in Arabidopsis. When overexpressed in rice, BSR2 also conferred resistance to two R. solani anastomosis groups. Both Arabidopsis and rice plants overexpressing BSR2 had slower growth and produced longer seeds than wild-type control plants. In contrast, BSR2-knockdown rice plants were more susceptible to R. solani and displayed faster growth and shorter seeds in comparison with the control. These results indicate that BSR2 is associated with disease resistance, growth rate and seed size in rice and suggest that its function is evolutionarily conserved in both monocot rice and dicot Arabidopsis.
真菌病原体立枯丝核菌会引起数百种植物物种的毁灭性疾病。在这些物种中，立枯丝核菌会引起叶鞘腐烂病，这是水稻的三大病害之一。迄今为止，仅有少数基因被报道能够赋予植物对立枯丝核菌的抗性。在这里，我们筛选了对细菌病原体丁香假单胞菌 pv. tomato DC3000 和真菌病原体炭疽菌具有抗性的水稻-FOX 拟南芥品系，以检测它们对立枯丝核菌的抗性。BSR2 基因编码一种未被鉴定的细胞色素 P450 蛋白，属于 CYP78A 家族，该基因赋予拟南芥对立枯丝核菌的抗性。当在水稻中过表达时，BSR2 也赋予了对两种立枯丝核菌吻合群的抗性。过表达 BSR2 的拟南芥和水稻植株的生长速度比野生型对照植株慢，种子也更长。相比之下，与对照相比，bsr2 敲低的水稻植株更容易感染立枯丝核菌，生长速度更快，种子更短。这些结果表明，BSR2 与水稻的抗病性、生长速度和种子大小有关，并表明其功能在单子叶水稻和双子叶拟南芥中是进化保守的。
