Jianyuan Li, Xiaodong Wang, Lirong Zhang, Qingfang Meng, Na Zhang, Wenxiang Yang, Daqun Liu
Department of Plant Pathology, Agricultural University of Hebei, Biological Control Center of Plant Diseases and Plant Pests of Hebei Province, National Engineering Research Center for Agriculture in Northern Mountainous Areas, Baoding 071001, China.
Department of Plant Pathology, Agricultural University of Hebei, Biological Control Center of Plant Diseases and Plant Pests of Hebei Province, National Engineering Research Center for Agriculture in Northern Mountainous Areas, Baoding 071001, China.
Plant Physiol Biochem. 2017 Oct;119:1-8. doi: 10.1016/j.plaphy.2017.08.009. Epub 2017 Aug 15.
Wheat leaf rust, caused by Puccinia triticina (Pt), is one of the most severe fungal diseases on wheat globally. Rational utilization of wheat leaf rust resistance (Lr) genes is still the best choice for control this disease. Wheat seedlings carrying Lr19 showed a high resistance phenotype to all Pt races in China. So far, all the cloned seedling Lr genes including Lr1, Lr10 and Lr21, encode protein with NBS-LRR domain. In this study, a wheat gene with NBS-LRR domain from previously established Lr19-resistance-related cDNA library was cloned and designated as TaRGA19. Full length of this gene was amplified by rapid amplification of cDNA ends (RACE). By blast against IWGSC wheat genome database, we have noticed that TaRGA19 was located on chromosome 2DS, which was different from Lr19 located on chromosome 7DL. Compared with susceptible Thatcher line, expression level of TaRGA19 was upregulated in wheat isogenic lines carrying Lr19 (TcLr19) after inoculation of Pt race THTS. By particle bombardment, TaRGA19-GFP fused protein was localized on plasma membrane of epidermal cells. Using virus-induced gene silencing (VIGS), TaRGA19-knockdown plants of TcLr19 showed reduced resistance and few sporulation phenotype upon Pt challenge. Further histological observation indicated that Pt hyphal growth at the infection sites was less suppressed in the TaRGA19-knockdown plants. In conclusion, we speculate this TaRGA19 gene was involved in the Lr19-mediated resistance to wheat leaf rust along with other components.
由小麦叶锈菌（Puccinia triticina，Pt）引起的小麦叶锈病是全球小麦上最严重的真菌病害之一。合理利用小麦叶锈病抗性（Lr）基因仍然是防治该病的最佳选择。携带Lr19的小麦幼苗对中国所有的Pt小种都表现出高抗表型。到目前为止，所有已克隆的苗期Lr基因，包括Lr1、Lr10和Lr21，都编码具有NBS-LRR结构域的蛋白质。在本研究中，从先前建立的与Lr19抗性相关的cDNA文库中克隆了一个具有NBS-LRR结构域的小麦基因，并将其命名为TaRGA19。通过cDNA末端快速扩增（RACE）技术扩增了该基因的全长。通过与国际小麦基因组测序联盟（IWGSC）小麦基因组数据库进行比对，我们发现TaRGA19位于2DS染色体上，这与位于7DL染色体上的Lr19不同。与感病的Thatcher品系相比，在接种Pt小种THTS后，携带Lr19的小麦近等基因系（TcLr19）中TaRGA19的表达水平上调。通过粒子轰击，TaRGA19-GFP融合蛋白定位于表皮细胞的质膜上。利用病毒诱导基因沉默（VIGS）技术，TcLr19的TaRGA19基因沉默植株在受到Pt侵染时表现出抗性降低和产孢减少的表型。进一步的组织学观察表明，在TaRGA19基因沉默植株中，Pt在侵染部位的菌丝生长受到的抑制较小。总之，我们推测该TaRGA19基因与其他组分一起参与了Lr19介导的小麦叶锈病抗性反应。
