Leibman Diana, Pashkovsky Ekaterina, Shnaider Yulia, Shtarkman Meital, Gaba Victor, Gal-On Amit
Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O. Box 15159, Rishon LeZion 7505101, Israel.
Plants (Basel). 2022 Jul 7;11(14):1795. doi: 10.3390/plants11141795.
RNA-dependent RNA polymerase 1 (RDR1) plays a crucial defense role against plant viruses by secondary amplification of viral double-stranded RNA in the gene-silencing pathway. In this study, it was found that melon encodes four RDR1 genes ( and similar to the gene family of cucumber (. ). However, in contrast to cucumber, melon harbors a truncated gene. In healthy plants, was expressed, whereas the expression of was not detected. expression level increased 20-fold upon cucumber mosaic virus (CMV) infection and was not increased in melon plants infected with zucchini yellow mosaic virus (ZYMV), cucumber vein yellowing virus (CVYV) and cucumber green mottle mosaic virus (CGMMV). The expression of genes was induced differentially by infection with viruses from different families: high levels of ~340-, 172- and 115-fold increases were induced by CMV, CVYV and CGMMV, respectively, and relatively low-level increases by potyvirus infection (4- to 6-fold). CMV mutants lacking the viral silencing suppressor 2b protein did not cause increased expression; knockout of by CRISPR/Cas9 increased susceptibility to CMV but not to ZYMV. Therefore, it is suggested that the sensitivity of melon to viruses from different families is a result of the loss of function of .
RNA依赖的RNA聚合酶1（RDR1）通过在基因沉默途径中对病毒双链RNA进行二次扩增，在植物抵御病毒方面发挥着关键的防御作用。在本研究中，发现甜瓜编码四个RDR1基因（与黄瓜的基因家族相似）。然而，与黄瓜不同的是，甜瓜含有一个截短的基因。在健康植株中，基因表达，而未检测到基因的表达。黄瓜花叶病毒（CMV）感染后，基因表达水平增加了20倍，而感染小西葫芦黄花叶病毒（ZYMV）、黄瓜叶脉黄化病毒（CVYV）和黄瓜绿斑驳花叶病毒（CGMMV）的甜瓜植株中该基因表达未增加。不同病毒家族感染对基因的表达诱导存在差异：CMV、CVYV和CGMMV分别诱导基因表达水平高水平增加约340倍、172倍和115倍，而马铃薯Y病毒感染诱导的增加水平相对较低（4至6倍）。缺乏病毒沉默抑制子2b蛋白的CMV突变体不会导致基因表达增加；通过CRISPR/Cas9敲除基因会增加对CMV的易感性，但对ZYMV的易感性未增加。因此，表明甜瓜对不同病毒家族的敏感性是基因功能丧失的结果。
