Zhang Chao, Xie Hui, Cheng Xi, Wang Dong-Wei, Li Yu, Xu Chun-Ling, Huang Xin
Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Guangdong Province Key Laboratory of Microbial Signals and Disease Control / Department of Plant Pathology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, People's Republic of China; Institute of Genetic Engineering, Southern Medical University, Guangzhou, Guangdong, People's Republic of China.
Laboratory of Plant Nematology and Research Center of Nematodes of Plant Quarantine, Guangdong Province Key Laboratory of Microbial Signals and Disease Control / Department of Plant Pathology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, People's Republic of China.
PLoS One. 2015 Mar 3;10(3):e0118414. doi: 10.1371/journal.pone.0118414. eCollection 2015.
Fatty acid- and retinoid-binding protein (FAR) is a nematode-specific protein expressed in the nematode hypodermis. It is involved in nematode development, reproduction, and infection and can disrupt the plant defense reaction. In this study, we obtained the full-length sequence of the far gene from Radopholus similis (Rs-far-1), which is 828 bp long and includes a 558 bp ORF encoding 186 amino acids. A protein homology analysis revealed that Rs-FAR-1 is 75% similar to Mj-FAR-1 from Meloidogyne javanica. A neighbor-joining phylogenetic tree was inferred and showed that Rs-FAR-1 is most similar to Pv-FAR-1 from Pratylenchus vulnus. A fluorescence-based ligand-binding analysis confirmed that Rs-FAR-1 can combine with fatty acids and retinol. qPCR was used to assess Rs-far-1 expression levels at different developmental stages in different R. similis populations, and its expression was 2.5 times greater in the highly pathogenic Rs-C population than in the less pathogenic Rs-P population. The highest expression was found in females, followed by eggs, juveniles and males. When R. similis was treated with Rs-far-1 dsRNA for 36 h, the reproduction and pathogenicity decreased significantly. In situ hybridization revealed Rs-far-1 transcripts in the R. similis hypodermis. Additionally, R. similis treated with Rs-far-1 dsRNA or water were inoculated into Arabidopsis thaliana. Allene oxide synthase (AOS) expression in A. thaliana was upregulated during early infection in both treatments and then returned to the expression levels of the control plant. Compared with the control plant, AOS expression significantly decreased in A. thaliana inoculated with water-treated R. similis but significantly increased in A. thaliana inoculated with Rs-far-1 dsRNA-treated R. similis. This finding indicates that Rs-far-1 regulates AOS expression in A. thaliana. Rs-FAR-1 plays a critical role in R. similis development, reproduction, and infection and can disturb the plant defense reaction. Therefore, Rs-far-1 is an important target gene to control R. similis.
脂肪酸和视黄醇结合蛋白（FAR）是一种在线虫皮下表达的线虫特异性蛋白。它参与线虫的发育、繁殖和感染，并能破坏植物的防御反应。在本研究中，我们从相似穿孔线虫（Rs-far-1）中获得了far基因的全长序列，其长度为828 bp，包含一个558 bp的开放阅读框，编码186个氨基酸。蛋白质同源性分析表明，Rs-FAR-1与爪哇根结线虫的Mj-FAR-1有75%的相似性。推断出的邻接法系统发育树表明，Rs-FAR-1与穿刺短体线虫的Pv-FAR-1最为相似。基于荧光的配体结合分析证实，Rs-FAR-1可以与脂肪酸和视黄醇结合。qPCR用于评估不同相似穿孔线虫种群在不同发育阶段的Rs-far-1表达水平，其在高致病性的Rs-C种群中的表达量是低致病性的Rs-P种群中的2.5倍。在雌性中表达最高，其次是卵、幼虫和雄性。当相似穿孔线虫用Rs-far-1双链RNA处理36小时后，其繁殖力和致病性显著下降。原位杂交显示相似穿孔线虫皮下有Rs-far-1转录本。此外，将用Rs-far-1双链RNA或水处理的相似穿孔线虫接种到拟南芥中。在两种处理的早期感染过程中，拟南芥中的丙二烯氧化物合酶（AOS）表达均上调，然后恢复到对照植物的表达水平。与对照植物相比，接种水处理的相似穿孔线虫的拟南芥中AOS表达显著下降，但接种Rs-far-1双链RNA处理的相似穿孔线虫的拟南芥中AOS表达显著增加。这一发现表明，Rs-far-1调节拟南芥中AOS的表达。Rs-FAR-1在相似穿孔线虫的发育、繁殖和感染中起关键作用，并能干扰植物的防御反应。因此，Rs-far-1是控制相似穿孔线虫的重要靶基因。
