Chen Tingting, Xiao Jin, Xu Jun, Wan Wentao, Qin Bi, Cao Aizhong, Chen Wei, Xing Liping, Du Chen, Gao Xiquan, Zhang Shouzhong, Zhang Ruiqi, Shen Wenbiao, Wang Haiyan, Wang Xiue
The State Key Laboratory of Crop Genetics and Germplasm Enhancement, Cytogenetics Institute, Nanjing Agricultural University/JCIC-MCP, Nanjing, Jiangsu, 210095, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Sciences, Anyang, Henan, 455000, China.
BMC Plant Biol. 2016 Jan 25;16:27. doi: 10.1186/s12870-016-0713-8.
Powdery mildew, caused by Blumeria graminearum f.sp. tritici (Bgt), is one of the most severe fungal diseases of wheat. The exploration and utilization of new gene resources is the most effective approach for the powdery mildew control.
We report the cloning and functional analysis of two wheat LRR-RLKs from T. aestivum c.v. Prins- T. timopheevii introgression line IGV1-465, named TaRLK1 and TaRLK2, which play positive roles in regulating powdery mildew resistance in wheat. The two LRR-RLKs contain an ORF of 3,045 nucleotides, encoding a peptide of 1014 amino acids, with seven amino acids difference. Their predicted proteins possess a signal peptide, several LRRs, a trans-membrane domain, and a Ser/Thr protein kinase domain. In response to Bgt infection, the TaRLK1/2 expression is up-regulated in a developmental-stage-dependent manner. Single-cell transient over-expression and gene-silencing assays indicate that both genes positively regulate the resistance to mixed Bgt inoculums. Transgenic lines over-expressing TaRLK1 or TaRLK2 in a moderate powdery mildew susceptible wheat variety Yangmai 158 led to significantly enhanced powdery mildew resistance. Exogenous applied salicylic acid (SA) or hydrogen peroxide (H2O2) induced the expression of both genes, and H2O2 had a higher accumulation at the Bgt penetration sites in RLK over-expression transgenic plants, suggesting a possible involvement of SA and altered ROS homeostasis in the defense response to Bgt infection. The two LRR-RLKs are located in the long arm of wheat chromosome 2B, in which the powdery mildew resistance gene Pm6 is located, but in different regions.
Two members of TaRLK family were cloned from IGV1-465. TaRLK1 and TaRLK2 contribute to powdery mildew resistance of wheat, providing new resistance gene resources for wheat breeding.
由小麦白粉病菌（Blumeria graminearum f.sp. tritici，Bgt）引起的白粉病是小麦最严重的真菌病害之一。探索和利用新的基因资源是防治白粉病最有效的途径。
我们报道了从小麦品种普林斯 - 提莫菲维小麦渗入系IGV1 - 465中克隆并对两个小麦LRR - RLK基因进行功能分析，分别命名为TaRLK1和TaRLK2，它们在调控小麦对白粉病的抗性中发挥正向作用。这两个LRR - RLK基因含有一个3045个核苷酸的开放阅读框，编码一个1014个氨基酸的肽段，两者相差7个氨基酸。它们预测的蛋白质具有一个信号肽、几个富含亮氨酸重复序列（LRR）、一个跨膜结构域和一个丝氨酸/苏氨酸蛋白激酶结构域。响应Bgt感染，TaRLK1/2的表达以发育阶段依赖的方式上调。单细胞瞬时过表达和基因沉默试验表明，这两个基因均正向调控对混合Bgt接种物的抗性。在中度感白粉病的小麦品种扬麦158中过表达TaRLK1或TaRLK2的转基因株系对白粉病的抗性显著增强。外源施加水杨酸（SA）或过氧化氢（H2O2）诱导了这两个基因的表达，并且在RLK过表达转基因植株的Bgt侵染位点H2O2积累更高，这表明SA和ROS内稳态改变可能参与了对Bgt感染的防御反应。这两个LRR - RLK基因位于小麦2B染色体长臂上，其中白粉病抗性基因Pm6也位于该染色体上，但在不同区域。
从IGV1 - 465中克隆了TaRLK家族的两个成员。TaRLK1和TaRLK2有助于小麦对白粉病的抗性，为小麦育种提供了新的抗性基因资源。
