Nithya K, Parameswari B, Kumar Subham, Annadurai A, Nithyanantham R, Mahadevaswamy H K, Viswanathan R
ICAR-Sugarcane Breeding Institute, Coimbatore, 641007 India.
ICAR-National Bureau of Plant Genetic Resources, Regional Station, Hyderabad, 500030 India.
3 Biotech. 2023 May;13(5):125. doi: 10.1007/s13205-023-03541-y. Epub 2023 Apr 8.
In sugarcane ( spp. hybrids) cultivation, viral diseases pose a great challenge across the globe. Yellow leaf (YL) disease is one of the important viral diseases caused by (ScYLV), a positive-sense ssRNA virus, genus , family The disease symptoms appear in later stages of crop growth during grand growth to maturity phase with intense midrib yellowing in the abaxial leaf surface. At present, this disease is managed through tissue (meristem) culture and healthy seed nurseries in India. However, the virus-free plants are infected quickly by secondary inoculum from aphid vectors in the field, which necessitates the importance of developing YL-resistant varieties. We screened about 600-625 sugarcane parental clones to identify true YL resistance based on 0-5 disease rating scale since 2015 and categorised them as resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible. Leaf samples were collected from all these categories of plants during 2018-20 for the viral titre estimation through absolute quantification method (qRT-PCR assay). The viral load was invariably high in all categories of susceptible samples that ranged from 4.40 × 10 to 8.429 × 10, whereas in YL-free asymptomatic clones, the viral load ranged from 82.35 ± 5.90 to 5.121 × 10. The results clearly indicated that highest viral titre of 10-10 copies was present in all the susceptible clones irrespective of their disease severity grades. Our results clearly established that about 22.85% of apparently resistant sugarcane clones remained free from YL symptoms with significantly low ScYLV titre although we could not find a significant correlation between virus titre and symptom expression. The identified resistant parents will serve as sources of YL resistance to develop virus resistant sugarcane varieties.
The online version contains supplementary material available at 10.1007/s13205-023-03541-y.
在甘蔗（ spp. 杂交种）种植中，病毒病在全球范围内构成了巨大挑战。黄叶（YL）病是由甘蔗黄化病毒（ScYLV）引起的重要病毒病之一，ScYLV是一种正义单链RNA病毒，属于黄症病毒属，黄症病毒科。该病症状出现在作物生长的后期，即从旺盛生长到成熟阶段，叶片背面中脉强烈发黄。目前，印度通过组织（分生组织）培养和健康种苗圃来管理这种疾病。然而，无病毒植株在田间很快会被蚜虫传播的二次接种物感染，这凸显了培育抗YL品种的重要性。自2015年以来，我们根据0至5级病害评级标准，对约600 - 625个甘蔗亲本克隆进行了筛选，以确定真正的抗YL能力，并将它们分为抗性、中度抗性、中度敏感、敏感和高度敏感类别。在2018 - 2020年期间，从所有这些类别的植株上采集叶片样本，通过绝对定量方法（qRT - PCR检测）进行病毒滴度估计。所有敏感样本类别中的病毒载量始终很高，范围从4.40×10 到8.429×10，而在无YL无症状克隆中，病毒载量范围从82.35±5.90到5.121×10。结果清楚地表明，所有敏感克隆中病毒滴度最高为10 - 10拷贝，无论其病害严重程度等级如何。我们的结果清楚地表明，约22.85%看似抗性的甘蔗克隆没有出现YL症状，ScYLV滴度显著较低，尽管我们未发现病毒滴度与症状表达之间存在显著相关性。所鉴定出的抗性亲本将作为抗YL的来源，用于培育抗病毒甘蔗品种。
在线版本包含可在10.1007/s13205 - 023 - 03541 - y获取的补充材料。
