Alagu Kokila, Perumal Renukadevi, Iruthayasamy Johnson, Arjunan Sankari, Angappan Suganthi, Shanmugam Varanavasiappan, Varagur Ganesan Malathi
Tamil Nadu Agricultural University, Coimbatore, India.
Retired Scientist, ICAR-IARI, New Delhi, India.
3 Biotech. 2025 Jul;15(7):198. doi: 10.1007/s13205-025-04359-6. Epub 2025 May 30.
Begomoviruses such as bhendi yellow vein mosaic virus (Begomovirus abelmoschusflavi (BYVMV)) and okra enation leaf curl virus (Begomovirus abelsmoschusenation (OELCuV)) pose serious threats to okra (Abelmoschus esculentus) production. It is essential to comprehend how these viruses spread, in order to develop efficient disease control strategies. Initially, virus infected leaf, flower and fruit samples collected from fields were subjected to DAS-ELISA, in which the whole seed recorded highest OD value (3.10 in Coimbatore; 2.31 in Salem) from infected plants. All ELISA positive samples were subjected to PCR using specific primers for BYVMV and OELCuV for AV1 region of DNA A, none of the samples were amplified for BYVMV specific primers, whereas all the samples were amplified for OELCuV specific primers. A representative of two OELCuV PCR positive embryo samples of Thondamuthur (CBE isolate) and Edapadi (EDP) were sequenced and submitted in NCBI (Accession Numbers: CBE- PQ963865; EDP: PV126629), which showed 99-100% similarity with Tamil Nadu and Andhra Pradesh OELCuV isolates. Further to confirm seed transmission, grow-out test was carried out using two hybrid seeds namely H1 and H2 (Market seeds) under insect proof conditions. DAS-ELISA was performed for the leaf samples collected from grow-out test plants on 30th day after sowing. Out of 198 seedlings of H1, the presence of begomovirus was detected in 56 plants, whereas in hybrid H2, 12 plants were tested positive among 100 seedlings. The 198 samples of H1 and 100 samples of H2 were also subjected to PCR with specific primers for BYVMV and OELCV to detect the presence of viruses. BYVMV was not detected in any hybrid by PCR analysis. But OELCuV was found in 21.7% of H1 and 4% of H2 samples with the amplicon size of ~606bp. The seed transmission rate was higher in H1 compared to H2 hybrid. The plants which showed positive for OELCuV didn't express any pattern of symptoms and were asymptomatic. Though the seedlings were asymptomatic, they harboured the virus and could serve as inoculum source for whitefly transmission. The above findings highlight the significance of seed transmission serving as a potential source for active spread of the disease. To our knowledge, this is the first report on seed transmission of OELCuV.
The online version contains supplementary material available at 10.1007/s13205-025-04359-6.
像黄秋葵脉花叶病毒（黄秋葵黄脉花叶病毒（BYVMV））和秋葵脉突叶卷曲病毒（秋葵脉突病毒（OELCuV））这样的双生病毒对秋葵（黄秋葵）生产构成严重威胁。了解这些病毒如何传播对于制定有效的疾病控制策略至关重要。最初，从田间采集的病毒感染的叶片、花朵和果实样本进行了双抗夹心酶联免疫吸附测定（DAS-ELISA），其中从受感染植物收获的整个种子记录到最高光密度值（哥印拜陀为3.10；塞勒姆为2.31）。所有酶联免疫吸附测定阳性样本使用针对DNA A的AV1区域的BYVMV和OELCuV特异性引物进行聚合酶链反应（PCR），没有样本被BYVMV特异性引物扩增，而所有样本都被OELCuV特异性引物扩增。来自通达穆图尔（CBE分离株）和埃达帕迪（EDP）的两个OELCuV PCR阳性胚样本的一个代表进行了测序，并提交到美国国立生物技术信息中心（NCBI）（登录号：CBE - PQ963865；EDP：PV126629），其与泰米尔纳德邦和安得拉邦的OELCuV分离株显示出99 - 100%的相似性。为进一步确认种子传播，在防虫条件下使用两个杂交种子H1和H2（市售种子）进行了实生苗测试。在播种后第30天对从实生苗测试植株采集的叶片样本进行了DAS-ELISA。在H1的198株幼苗中，56株检测到双生病毒存在，而在杂交种H2中，100株幼苗中有12株检测呈阳性。H1的198个样本和H2的100个样本也使用针对BYVMV和OELCV的特异性引物进行PCR以检测病毒的存在。通过PCR分析在任何杂交种中均未检测到BYVMV。但在H1的21.7%和H2的4%样本中发现了OELCuV，扩增片段大小约为606bp。H1的种子传播率高于H2杂交种。显示OELCuV呈阳性的植株未表现出任何症状模式且无症状。尽管幼苗无症状，但它们携带病毒，可作为粉虱传播的接种源。上述发现突出了种子传播作为疾病活跃传播潜在来源的重要性。据我们所知，这是关于OELCuV种子传播的首次报道。
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