INRA, UMR 1332 de Biologie du fruit et Pathologie, Villenave d'Ornon, France.
PLoS One. 2012;7(6):e39169. doi: 10.1371/journal.pone.0039169. Epub 2012 Jun 18.
The non conventional RTM (Restricted Tobacco etch virus Movement) resistance which restricts long distance movement of some plant viruses in Arabidopsis thaliana is still poorly understood. Though at least three RTM genes have been identified, their precise role(s) in the process as well as whether other genes are involved needs to be elucidated.
METHODOLOGY/PRINCIPAL FINDINGS: In this study, the natural variation of the RTM genes was analysed at the amino acid level in relation with their functionality to restrict the long distance movement of Lettuce mosaic potyvirus (LMV). We identified non-functional RTM alleles in LMV-susceptible Arabidopsis accessions as well as some of the mutations leading to the non-functionality of the RTM proteins. Our data also indicate that more than 40% of the resistant accessions to LMV are controlled by the RTM genes. In addition, two new RTM loci were genetically identified.
CONCLUSIONS/SIGNIFICANCE: Our results show that the RTM resistance seems to be a complex biological process which would involves at least five different proteins. The next challenges will be to understand how the different RTM protein domains are involved in the resistance mechanism and to characterise the new RTM genes for a better understanding of the blocking of the long distance transport of plant viruses.
非传统 RTM（限制烟草蚀纹病毒运动）抗性限制了一些植物病毒在拟南芥中的远距离运动，但目前对此了解甚少。尽管已经鉴定出至少三个 RTM 基因，但它们在该过程中的精确作用以及是否涉及其他基因仍需要阐明。
方法/主要发现：在这项研究中，分析了 RTM 基因在氨基酸水平上的自然变异与限制莴苣花叶病毒（LMV）长距离运动的功能之间的关系。我们在 LMV 敏感的拟南芥品系中鉴定到了无功能的 RTM 等位基因，以及导致 RTM 蛋白无功能的一些突变。我们的数据还表明，超过 40%的 LMV 抗性品系受 RTM 基因控制。此外，还遗传鉴定出了两个新的 RTM 基因座。
结论/意义：我们的结果表明，RTM 抗性似乎是一个复杂的生物学过程，至少涉及五个不同的蛋白质。接下来的挑战将是了解不同的 RTM 蛋白结构域如何参与抗性机制，并对新的 RTM 基因进行特征描述，以更好地理解植物病毒长距离运输的阻断。
