Huangfu Jiayi, Li Jiancai, Li Ran, Ye Meng, Kuai Peng, Zhang Tongfang, Lou Yonggen
State Key Laboratory of Rice Biology, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China.
Int J Mol Sci. 2016 May 31;17(6):697. doi: 10.3390/ijms17060697.
WRKY transcription factors play a central role not only in plant growth and development but also in plant stress responses. However, the role of WRKY transcription factors in herbivore-induced plant defenses and their underlying mechanisms, especially in rice, remains largely unclear. Here, we cloned a rice WRKY gene OsWRKY45, whose expression was induced by mechanical wounding, by infestation of the brown planthopper (BPH, Nilaparvata lugens) and by treatment with jasmonic acid (JA) or salicylic acid (SA). The antisense expression of OsWRKY45 (as-wrky) enhanced BPH-induced levels of H₂O₂ and ethylene, reduced feeding and oviposition preference as well as the survival rate of BPH, and delayed the development of BPH nymphs. Consistently, lower population densities of BPH on as-wrky lines, compared to those on wild-type (WT) plants, were observed in field experiments. On the other hand, as-wrky lines in the field had lower susceptibility to sheath blight (caused by Rhizoctonia solani) but higher susceptibility to rice blast (caused by Magnaporthe oryzae) than did WT plants. These findings suggest that OsWRKY45 plays important but contrasting roles in regulating the resistance of rice to pathogens and herbivores, and attention should be paid if OsWRKY45 is used to develop disease or herbivore-resistant rice.
WRKY转录因子不仅在植物生长发育中起核心作用，还在植物应激反应中发挥关键作用。然而，WRKY转录因子在食草动物诱导的植物防御中的作用及其潜在机制，尤其是在水稻中，仍 largely不清楚。在这里，我们克隆了一个水稻WRKY基因OsWRKY45，其表达受到机械损伤、褐飞虱（BPH，Nilaparvata lugens）侵染以及茉莉酸（JA）或水杨酸（SA）处理的诱导。OsWRKY45的反义表达增强了BPH诱导的H₂O₂和乙烯水平，降低了BPH的取食和产卵偏好以及存活率，并延缓了BPH若虫的发育。一致地，在田间试验中观察到，与野生型（WT）植株相比，as-wrky株系上的BPH种群密度较低。另一方面，田间的as-wrky株系对纹枯病（由立枯丝核菌引起）的易感性较低，但对稻瘟病（由稻瘟病菌引起）的易感性高于WT植株。这些发现表明，OsWRKY45在调节水稻对病原体和食草动物的抗性中起重要但相反的作用，如果利用OsWRKY45培育抗病或抗食草动物的水稻，应予以关注。
