铁棍山药病毒鉴定及不同生长时期定量分析OA

Dioscorea opposita Thunb.,a prominent species among China's'Four Huai Medicines',possesses significant medicinal and edible value.Its cultivar D.opposita cv.'Tiegun'is particularly valued for its superior quality.However,prolonged vegetative propagation has led to severe viral infections,resulting in germplasm degeneration and yield decline in this crop.To clarify the viral species and their expression levels at different developmental stages of D.opposita cv.'Tiegun'in the authentic producing area of Jiaozuo,Henan,this study first employed small RNA deep sequencing technology to identify three viruses,namely Japanese yam mosaic virus(JYMV),yam latent virus(YLV),and broad bean wilt virus-2(BBWV-2),from the D.opposita cv.'Tiegun'samples collected from the National Yam Germplasm Repository of Wen County Institute of Agricultural Sciences(hereinafter referred to as the Wen County Repository).Subsequent comprehensive RT-PCR assays on samples from three distinct cultivation areas(the Wen County Repository,Fantian Town,and Qinyang City)confirmed the presence of four viruses:JYMV,yam yellow spot mosaic virus(YYSMV),BBWV-2,and YLV.JYMV and YYSMV were identified as the most prevalent,with average detection rates exceeding 99.0％across all surveyed regions.Quantitative RT-PCR analysis revealed that the expression levels of YYSMV,YLV,and JYMV followed a consistent pattern,increasing during early growth,peaking between 120 and 150 days after sowing,and subsequently declining.In contrast,BBWV-2 exhibited persistently low expression throughout all monitored stages.Based on these expression dynamics,the optimal period for collecting explants for shoot-tip-based virus eradication was determined to be approximately 120 days post-sowing(within a 110-130 day window).This study provides the first systematic report on the virome and growth-stage-specific viral expression patterns in D.opposita cv.'Tiegun'from its core production area.The findings offer crucial data for advancing virus-free planting material production and establish a scientific foundation for developing targeted,integrated disease management strategies tailored to regional viral prevalence.