广东甘蔗黄叶病田间调查及病原病毒的分子检测

 广东省粤北和粤西蔗区多个县市的田间甘蔗上观察到甘蔗黄叶病(Sugarcane yellow leaf disease,SYLD)典型症状,目前该病仅局部分布,但部分田块病株率为5%~80%,发病品种有青皮果蔗、黑皮果蔗、新台糖系列品种、粤糖79/177和粤糖93/159等。采集发病田间显症叶片、无症叶片和在病叶上取食的甘蔗绵蚜(Ceratovacuna lanigera)样品,抽提总RNA,以基于甘蔗黄叶病毒(Sugarcane yellow leaf virus,SCYLV) CP基因序列的特异引物进行一步RT-PCR和巢式PCR扩增,并对扩增产物进行核苷酸序列测定和BLAST比对。结果显示,RT-PCR及巢式PCR产物核苷酸序列与分离自巴西的SCYLV B1株系相应区段同一率为100%;一步RT-PCR可从约70%的显症叶片样品中检测到SCYLV,而病田中的无症叶片样品以及在病叶上取食的单头甘蔗绵蚜样品需经巢式PCR扩增方可检测到SCYLV,阳性率分别为1%~5%和83%。本研究表明,广东省栽培甘蔗已受到SCYLV侵染,甘蔗绵蚜携带SCYLV。

Occurrence of sugarcane yellow leaf disease in Guangdong and molecular detection of the virus pathogen

Sugarcane yellow leaf disease(SYLD) was observed at several sugarcane growing counties in north and west Guangdong province,China.Up to date,this disease was only found at limited area,but in some sugarcane fields the percentage of diseased plants reached 5%-80%.The varieties showing SYLD symptom included Badila(Qingpi and Heipi fruit sugarcane),ROC16,ROC22,ROC23,ROC25,Yuetang 79/177 and Yuetang 93/159.Total RNA was extracted from sugarcane leaves with or without yellow leaf symptom and aphids Ceratovacuna lanigera collected from diseased leaf,and amplified by one-step RTPCR and nested PCR using specific primers based on the CP gene sequence of Sugarcane yellow leaf virus(SCYLV).The amplified products were cloned and sequenced.It was showed that they shared 100% nucleotide identity with CP gene of SCYLV B1 strain from Brazil.Approximate 70% leaf samples showing SYLD symptom were SCYLV positive in one-step RT-PCR detection,and the subsequent nested PCR was indispensable for SCYLV detection from symptomless leaf(from SYLD fields) and individual aphids C.lanigera,with positive rates of 1%5% and 83% respectively.This result confirmed the occurrence of SCYLV in Guangdong province,China,and the presence of SCYLV in aphids C.lanigera.