Department of Plant Pathology, The Ohio State University, Wooster, OH 44691.
Department of Plant Pathology, The Ohio State University, Columbus, OH 43210.
Phytopathology. 2024 Feb;114(2):484-495. doi: 10.1094/PHYTO-05-23-0171-R. Epub 2024 Feb 26.
Maize lethal necrosis (MLN) is a viral disease caused by host co-infection by maize chlorotic mottle virus (MCMV) and a potyvirus, such as sugarcane mosaic virus (SCMV). The disease is most effectively managed by growing MLN-resistant varieties. However, the relative importance of MCMV and potyvirus resistance in managing this synergistic disease is poorly characterized. In this study, we evaluated the effects of SCMV and/or MCMV resistance on disease, virus titers, and synergism and explored expression patterns of known potyvirus resistance genes and MLN disease was significantly lower in both the MCMV-resistant and SCMV-resistant inbred lines compared with the susceptible control Oh28. Prior to 14 days postinoculation (dpi), MCMV titers in resistant lines N211 and KS23-6 were more than 100,000-fold lower than found in the susceptible Oh28. However, despite no visible symptoms, titer differences between MCMV-resistant and -susceptible lines were negligible by 14 dpi. In contrast, systemic SCMV titers in the potyvirus-resistant line, Pa405, ranged from 130,000-fold to 2 million-fold lower than susceptible Oh28 as disease progressed. Initial expression was up to 49,000-fold lower in Oh28 compared with other genotypes, whereas expression of was up to 4.5-fold lower. Measures of virus synergy indicate that whereas MCMV resistance is effective in early infection, strong potyvirus resistance is critical for reducing synergist effects of co-infection on MCMV titer. These results emphasize the importance of both potyvirus resistance and MCMV resistance in an effective breeding program for MLN management.
玉米坏死性萎蔫病（MLN）是一种病毒性疾病，由玉米褪绿斑驳病毒（MCMV）和马铃薯 Y 病毒（如甘蔗花叶病毒，SCMV）的宿主共同感染引起。种植 MLN 抗性品种是管理该疾病最有效的方法。然而，MCMV 和马铃薯 Y 病毒抗性在协同管理这种疾病中的相对重要性尚未得到充分描述。在这项研究中，我们评估了 SCMV 和/或 MCMV 抗性对疾病、病毒滴度和协同作用的影响，并探索了已知马铃薯 Y 病毒抗性基因的表达模式。与易感对照 Oh28 相比，MCMV 抗性和 SCMV 抗性近交系中的 MLN 疾病明显较低。在接种后 14 天（dpi）之前，抗性系 N211 和 KS23-6 中的 MCMV 滴度比易感 Oh28 中的滴度低 100,000 倍以上。然而，尽管没有明显的症状，但到 14 dpi 时，MCMV 抗性和易感系之间的滴度差异可以忽略不计。相比之下，随着疾病的进展，马铃薯 Y 病毒抗性系 Pa405 中的系统 SCMV 滴度比易感 Oh28 低 130,000 至 200 万倍。初始表达在 Oh28 中比其他基因型低 49,000 倍，而 的表达低 4.5 倍。病毒协同作用的衡量标准表明，MCMV 抗性在早期感染中有效，但强烈的马铃薯 Y 病毒抗性对于降低共同感染对 MCMV 滴度的协同作用至关重要。这些结果强调了在 MLN 管理的有效育种计划中，马铃薯 Y 病毒抗性和 MCMV 抗性的重要性。
