Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India.
Appl Biochem Biotechnol. 2023 Aug;195(8):5158-5179. doi: 10.1007/s12010-023-04402-3. Epub 2023 Feb 28.
The major threat to mungbean (Vigna radiata L.) cultivation in the Indian subcontinent is yellow mosaic diseases (YMD), caused by Begomovirus containing bipartite genomes (DNA-A and DNA-B). In the current study, we address the epidemiology of begomoviruses infecting mungbean plants in three YMD hotspot regions of India. Full-length genomic components of the viruses from the symptomatic leaves were cloned by rolling circle amplification (RCA) and sequenced. Mungbean yellow mosaic virus (MYMV) was detected in Bihar and mungbean yellow mosaic India virus (MYMIV) in Assam and Orissa. Furthermore, we studied the population structure and genetic diversity of MYMV and MYMIV isolates of Vigna species reported to date from India. Interestingly, based on phylogenetics, we observed independent evolution of DNA-A and coevolution of DNA-B of MYMV and MYMIV. This finding is supported by the high mutation rate and recombination events in DNA-B, particularly in BV1 and BC1 genes over DNA-A, with high transition/transversion bias (R) for DNA-A over DNA-B. To investigate the effect of Begomovirus infection in plants, we constructed infectious clones (i.e. MYMV and MYMIV) and inoculated them to eight mungbean genotypes, cowpea (Vigna unguiculata L.) and tobacco (Nicotiana benthamiana) through agroinfiltration. The infected plants developed varying degrees of typical YMD symptoms. Based on the disease severity score and viral titre, mungbean genotypes were categorized as highly susceptible to MYMV (ML267) and MYMIV (K851) and immune to MYMV (PDM139, SML668) and MYMIV (Pusa Vishal). Conclusively, our findings may help prevent an epidemic of YMD in Vigna species and develop mungbean genotypes resistant to YMD via breeding programs.
印度次大陆绿豆（Vigna radiata L.）种植的主要威胁是黄化花叶病（YMD），由含有二分体基因组（DNA-A 和 DNA-B）的贝科病毒引起。在本研究中，我们调查了印度三个 YMD 热点地区感染绿豆植物的贝科病毒的流行病学。通过滚环扩增（RCA）克隆并测序了来自症状叶片的病毒全长基因组组件。在比哈尔邦检测到绿豆黄花叶病毒（MYMV），在阿萨姆邦和奥里萨邦检测到绿豆黄花叶印度病毒（MYMIV）。此外，我们研究了迄今为止从印度报道的 Vigna 种的 MYMV 和 MYMIV 分离物的种群结构和遗传多样性。有趣的是，基于系统发育，我们观察到 DNA-A 的独立进化和 MYMV 和 MYMIV 的 DNA-B 的共进化。这一发现得到了 DNA-B 中高突变率和重组事件的支持，特别是在 BV1 和 BC1 基因上，DNA-A 上的转换/颠换偏向性（R）高于 DNA-B。为了研究 Begomovirus 感染对植物的影响，我们构建了传染性克隆（即 MYMV 和 MYMIV），并通过农杆菌浸润将它们接种到 8 个绿豆基因型、豇豆（Vigna unguiculata L.）和烟草（Nicotiana benthamiana）上。受感染的植物表现出不同程度的典型 YMD 症状。根据疾病严重程度评分和病毒滴度，将绿豆基因型分为对 MYMV（ML267）和 MYMIV（K851）高度敏感，对 MYMV（PDM139、SML668）和 MYMIV（Pusa Vishal）免疫。总之，我们的研究结果可能有助于防止 Vigna 种中 YMD 的流行，并通过育成计划开发对 YMD 具有抗性的绿豆基因型。
