Ahsan Muhammad, Ashfaq Muhammad, Amer Mahmoud Ahmed, Shakeel Muhammad Taimoor, Mehmood Mirza Abid, Umar Muhammad, Al-Saleh Mohammed Ali
Institute of Environmental and Agricultural Sciences, University of Okara, Okara 56300, Pakistan.
Department of Plant Pathology, Balochistan Agriculture College, Quetta 87100, Pakistan.
Plants (Basel). 2023 Oct 8;12(19):3503. doi: 10.3390/plants12193503.
(ZYMV) is a severe threat to cucurbit crops worldwide, including Pakistan. This study was pursued to evaluate the prevalence, geographic distribution, and molecular diversity of ZYMV isolates infecting cucurbits in Pakistan's Pothwar region. Almost all the plant viruses act as a biotic stress on the host plants, which results in a yield loss. These viruses cause losses in single-infection or in mixed-infection cucurbit crops, and we have found a number of mixed-infected samples belonging to the family. Serological detection of the tested potyviruses in the collected cucurbit samples revealed that ZYMV was the most prevalent virus, with a disease incidence (DI) at 35.2%, followed by (PRSV) with an incidence of 2.2%, and (WMV) having an incidence as little as 0.5% in 2016. In the year 2017, a relatively higher disease incidence of 39.7%, 2.4%, and 0.3% for ZYMV, WMV, and PRSV, respectively, was recorded. ZYMV was the most prevalent virus with the highest incidence in Attock, Rawalpindi, and Islamabad, while PRSV was observed to be the highest in Islamabad and Jhelum. WMV infection was observed only in Rawalpindi and Chakwal. Newly detected Pakistani ZYMV isolates shared 95.8-97.0% nucleotide identities among themselves and 77.1-97.8% with other isolates retrieved from GenBank. Phylogenetic relationships obtained using different ZYMV isolates retrieved from GenBank and validated by in silico restriction analysis revealed that four Pakistani isolates clustered with other ZYMV isolates in group IIb with Chinese, Italian, Polish, and French isolates, while another isolate (MK848239) formed a separate minor clade within IIb. The isolate MK8482490, reported to infect bitter gourd in Pakistan, shared a minor clade with a Chinese isolate (KX884570). Recombination analysis revealed that the recently found ZYMV isolate (MK848239) is most likely a recombinant of Pakistani (MK848237) and Italian (MK956829) isolates, with a recombinant breakpoint between 266 and 814 nucleotide positions. Local isolate comparison and recombination detection may aid in the development of a breeding program that identifies resistant sources against recombinant isolates because the ZYMV is prevalent in a few cucurbit species grown in the surveyed areas and causes heavy losses and economic damage to the agricultural community.
小西葫芦黄花叶病毒（ZYMV）对包括巴基斯坦在内的全球葫芦科作物构成严重威胁。本研究旨在评估感染巴基斯坦波特瓦尔地区葫芦科作物的ZYMV分离株的流行情况、地理分布和分子多样性。几乎所有植物病毒都会对寄主植物造成生物胁迫，从而导致产量损失。这些病毒在单一感染或混合感染的葫芦科作物中都会造成损失，而且我们发现了许多属于该科的混合感染样本。对采集的葫芦科样本中检测的马铃薯Y病毒进行血清学检测发现，ZYMV是最普遍的病毒，发病率为35.2%，其次是番木瓜环斑病毒（PRSV），发病率为2.2%，西瓜花叶病毒（WMV）在2016年的发病率低至0.5%。2017年，ZYMV、WMV和PRSV的发病率相对较高，分别为39.7%、2.4%和0.3%。ZYMV是最普遍的病毒，在阿托克、拉瓦尔品第和伊斯兰堡发病率最高，而PRSV在伊斯兰堡和杰赫勒姆发病率最高。仅在拉瓦尔品第和查克瓦尔观察到WMV感染。新检测到的巴基斯坦ZYMV分离株彼此之间的核苷酸同一性为95.8 - 97.0%，与从GenBank检索到的其他分离株的同一性为77.1 - 97.8%。使用从GenBank检索到的不同ZYMV分离株获得的系统发育关系，并通过电子限制分析验证，结果显示四个巴基斯坦分离株与中国、意大利、波兰和法国的分离株在IIb组中与其他ZYMV分离株聚类，而另一个分离株（MK848239）在IIb组内形成一个单独的小分支。据报道，在巴基斯坦感染苦瓜的分离株MK8482490与一个中国分离株（KX884570）共享一个小分支。重组分析表明，最近发现的ZYMV分离株（MK848239）很可能是巴基斯坦分离株（MK848237）和意大利分离株（MK956829）的重组体，重组断点在266至814个核苷酸位置之间。局部分离株比较和重组检测可能有助于制定一个育种计划，该计划能够识别针对重组分离株的抗性来源，因为ZYMV在调查地区种植的一些葫芦科物种中普遍存在，并给农业社区造成严重损失和经济损害。
