BLASTX results for identified ORF4.

Potato Virus X (PVX) is a significant viral pathogen affecting potato (Solanum tuberosum) crops globally, yet its molecular characterization in Bangladesh remains limited. This study presents the first whole genome sequence (WGS) and molecular analysis of PVX isolated from potato plants in Gazipur, Bangladesh. Initial virus detection was performed using DAS-ELISA on symptomatic potato leaves, followed by RT-PCR targeting the coat protein (CP) gene, which confirmed PVX presence in ‘Patnai’ and ‘Challisha’ potato varieties through a 562 bp amplicon. The WGS of the Patnai-PVX isolate was determined to be 6,435 nucleotides long and deposited in GenBank (accession: PQ527059). Genome analysis identified five major open reading frames encoding the RNA-dependent RNA polymerase (RdRp), triple gene block proteins (TGBp1, TGBp2, TGBp3), and CP. Basic Local Alignment Search Tool X (BLASTX) analysis revealed high sequence similarity with PVX isolates from neighboring regions, suggesting evolutionary conservation. Mutation analysis identified 265 SNPs, predominantly synonymous mutations, indicating maintained protein-coding integrity despite genetic variation. Fewer non-synonymous mutations were detected, potentially affecting viral protein functions and pathogenicity. Phylogenetic analysis based on the entire genome sequence placed the Bangladeshi isolate (PQ527059.1) in a well-supported clade (bootstrap value 99%) with isolates from Peru (MT752634.1, MT752612.1, MT752621.1), highlighting potential international transmission routes while also exhibiting unique genetic markers indicative of regional specificity. This comprehensive molecular characterization enhances understanding of PVX genetic diversity and evolution in Bangladesh, providing valuable insights for developing effective virus management strategies in potato cultivation.马铃薯X病毒（Potato Virus X, PVX）是全球范围内危害马铃薯（Solanum tuberosum）作物的重要病毒性病原，但目前其在孟加拉国的分子特征研究仍较为有限。本研究首次报道了从孟加拉国加齐普尔地区马铃薯植株中分离得到的PVX全基因组序列（whole genome sequence, WGS）及其分子分析。研究首先通过双抗体夹心酶联免疫吸附试验（DAS-ELISA）对出现症状的马铃薯叶片进行病毒初筛检测，随后以外壳蛋白（coat protein, CP）基因为靶标开展反转录聚合酶链式反应（RT-PCR），通过扩增得到的562 bp片段确认‘Patnai’与‘Challisha’两个马铃薯品种均感染了PVX。本研究测定的Patnai-PVX分离株全基因组长度为6435个核苷酸，并已提交至GenBank数据库（登录号：PQ527059）。基因组分析显示其包含5个主要开放阅读框，分别编码RNA依赖的RNA聚合酶（RNA-dependent RNA polymerase, RdRp）、三重基因块蛋白（triple gene block proteins, TGBp1、TGBp2、TGBp3）以及CP。通过基本局部比对搜索工具X（Basic Local Alignment Search Tool X, BLASTX）分析发现，该分离株与邻近地区的PVX分离株序列相似性较高，提示其存在进化保守性。突变分析共鉴定出265个单核苷酸多态性（SNPs），其中绝大多数为同义突变，表明尽管存在遗传变异，其蛋白质编码完整性仍得以维持。检测到的非同义突变数量较少，这类突变可能会对病毒蛋白功能及致病性产生影响。基于全基因组序列的系统发育分析显示，孟加拉国分离株（PQ527059.1）与来自秘鲁的分离株（MT752634.1、MT752612.1、MT752621.1）共同处于一个支持度极高的进化分支（自举值99%），这既提示了潜在的国际传播途径，同时该分离株也存在体现区域特异性的独特遗传标记。本研究的全面分子特征解析加深了学界对孟加拉国PVX遗传多样性与进化的认识，可为马铃薯种植中制定高效的病毒防控策略提供重要参考价值。