College of Plant Protection, Shenyang Agricultural University, Shenyang, 110866, China.
Key Laboratory of Tobacco Pest Monitoring, Controlling & Integrated Management, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
BMC Microbiol. 2020 Mar 6;20(1):55. doi: 10.1186/s12866-020-01725-7.
Major latex proteins (MLPs) belong to the MLP subfamily in Bet v 1 protein family and respond to both biotic and abiotic stresses, which play critical roles in plant disease resistance. As the type species of widely distributed and economically devastating Potyvirus, Potato virus Y (PVY) is one of the major constraints to important crop plants including tobacco (Nicotiana benthamiana) worldwide. Despite the great losses owing to PVY infection in tobacco, there is no previous study investigating the potential role of MLPs in developing resistance to viral infection.
In this study, for the first time we have identified and functionally analyzed the MLP-like protein 28 from N. benthamiana, denoted as NbMLP28 and investigated its role in conferring resistance to N. benthamiana against PVY infection. NbMLP28 was localized to the plasmalemma and nucleus, with the highest level in the root. NbMLP28 gene was hypothesized to be triggered by PVY infection and was highly expressed in jasmonic acid (JA) signaling pathway. Further validation was achieved through silencing of NbMLP28 through virus-induced gene silencing (VIGS) that rendered N. benthamiana plants more vulnerable to PVY infection, contrary to overexpression that enhanced resistance.
Taken together, this is the first study describing the role of NbMLP28 in tobacco against PVY infection and provide a pivotal point towards obtaining pathogen-resistant tobacco varieties through constructing new candidate genes of MLP subfamily.
主要乳胶蛋白（MLPs）属于 Bet v 1 蛋白家族的 MLP 亚科，对生物和非生物胁迫均有反应，在植物抗病性中起着关键作用。作为广泛分布且具有经济破坏性的 Potyvirus 的模式种，马铃薯 Y 病毒（PVY）是包括烟草（Nicotiana benthamiana）在内的全球重要作物植物的主要限制因素之一。尽管由于 PVY 感染烟草造成了巨大损失，但之前没有研究调查 MLPs 在抗病毒感染方面的潜在作用。
在这项研究中，我们首次鉴定并功能分析了 N. benthamiana 中的 MLP 样蛋白 28，称为 NbMLP28，并研究了其在赋予烟草对 PVY 感染的抗性中的作用。NbMLP28 定位于质膜和核，在根中含量最高。假设 NbMLP28 基因是由 PVY 感染触发的，并在茉莉酸（JA）信号通路中高度表达。通过病毒诱导的基因沉默（VIGS）沉默 NbMLP28 进一步验证了这一点，这使得 N. benthamiana 植物更容易受到 PVY 感染，而不是通过过表达增强抗性。
总之，这是第一项描述 NbMLP28 在烟草中对 PVY 感染作用的研究，并为通过构建 MLP 亚科的新候选基因获得抗病原体烟草品种提供了一个关键点。
