Siskos Lampros, Antoniou Maria, Riado Jose, Enciso Montserrat, Garcia Carlos, Liberti Daniele, Esselink Danny, Baranovskiy Andrey G, Tahirov Tahir H, Visser Richard G F, Kormelink Richard, Bai Yuling, Schouten Henk J
Laboratory of Plant Breeding, Wageningen University and Research, Wageningen, Netherlands.
Sakata Vegetables Europe, Almeria, Spain.
Front Plant Sci. 2023 Mar 17;14:1130723. doi: 10.3389/fpls.2023.1130723. eCollection 2023.
The family of consists of more than 500 circular single-stranded (ss) DNA viral species that can infect numerous dicot and monocot plants. Geminiviruses replicate their genome in the nucleus of a plant cell, taking advantage of the host's DNA replication machinery. For converting their DNA into double-stranded DNA, and subsequent replication, these viruses rely on host DNA polymerases. However, the priming of the very first step of this process, i.e. the conversion of incoming circular ssDNA into a dsDNA molecule, has remained elusive for almost 30 years. In this study, sequencing of melon () accession K18 carrying the Tomato leaf curl New Delhi virus (ToLCNDV) recessive resistance quantitative trait locus (QTL) in chromosome 11, and analyses of DNA sequence data from 100 melon genomes, showed a conservation of a shared mutation in the () of all accessions that exhibited resistance upon a challenge with ToLCNDV. Silencing of (native) and subsequent challenging with three different geminiviruses showed a severe reduction in titers of all three viruses, altogether emphasizing an important role of in geminiviral replication. A model is presented explaining the role of during initiation of geminiviral DNA replication, i.e. as a regulatory subunit of primase that generates an RNA primer at the onset of DNA replication in analogy to -mediated initiation of DNA replication in all living organisms.
双生病毒科由500多种环状单链（ss）DNA病毒组成，这些病毒可感染多种双子叶和单子叶植物。双生病毒利用宿主的DNA复制机制在植物细胞核中复制其基因组。为了将其DNA转化为双链DNA并随后进行复制，这些病毒依赖宿主DNA聚合酶。然而，这个过程第一步（即将进入的环状ssDNA转化为dsDNA分子）的引发机制在近30年里一直未被揭示。在本研究中，对11号染色体上携带番茄卷叶新德里病毒（ToLCNDV）隐性抗性数量性状位点（QTL）的甜瓜（）种质K18进行测序，并对来自100个甜瓜基因组的DNA序列数据进行分析，结果表明，所有在受到ToLCNDV攻击时表现出抗性的种质，其（）中存在一个共享突变。对（天然的）进行沉默，随后用三种不同的双生病毒进行攻击，结果显示这三种病毒的滴度均大幅降低，这突出了在双生病毒复制中的重要作用。本文提出了一个模型，解释了在双生病毒DNA复制起始过程中的作用，即作为引发酶的调节亚基，在DNA复制开始时生成RNA引物，类似于所有生物体中由介导的DNA复制起始。
