广西甘蔗黄叶病调查及3种病毒基因型在广西的分布

Investigation of sugarcane yellow leaf virus(SCYLV) and geographical distribution of three genotypes in Guangxi

[目的]探明甘蔗黄叶病在广西蔗区的发生情况,明确甘蔗黄叶病毒（SCYLV）基因型类型和地理分布,为甘蔗抗病育种和健康种苗生产提供科学依据.[方法]从广西蔗区采集不同品种（品系）显症或不显症甘蔗样品,采用特异引物（P1/P2）进行RT-PCR检测.甘蔗黄叶病病毒基因型鉴定采用3对特异引物BRA-PER-F/BRA-PER-R、REU-F/B-REVd和CUB-F/CUB-R进行RT-PCR鉴定.[结果]SCYLV RT-PCR检测结果,124个样品中有57个样品可扩增出大小约630 bp的目的条带,扩增产物与GenBank中已报道的SCYLV CP基因序列同源性达95％～99％.甘蔗黄叶病调查结果,124个样品中57个样品检测出SCYLV,感染率为46.0％.广西北部蔗区黄叶病感染最严重,SCYLV检出率为76.0％;桂西、桂中、桂南蔗区分别有50.0％、40.0％和36.8％的品种检出SCYLV;桂东蔗区SCYLV阳性检测率最低,为16.6％.在所调查的甘蔗品种中以柳城03-182、桂糖21、粤糖55和粤糖93-159感染SCYLV比较严重,主栽品种ROC22在柳城、宜州、钦州和金光农场均检测出阳性.病毒基因型调查结果,广西甘蔗黄叶病病毒基因型存在巴西-秘鲁（BRA-PER）、留尼汪岛（REU）和古巴（CUB）基因型等3种.主要以CUB型为主,占63.2％,除东部和西部蔗区外其他蔗区均有分布;其次是BRA-PER基因型,占56.1％,每个生态蔗区均有分布;REU基因型占5.3％,分布于柳州、凭祥、南宁蔗区.[结论]甘蔗黄叶病SCYLV已在广西各主要蔗区发生且蔓延,其病毒基因型存在3种且有不同程度分布.

[Objective]The occurrence of sugarcane yellow leaf virus （SCYLV） disease and geographical distribution of SCYLV genotypes in sugarcane growing areas were investigated to provide scientific references for sugarcane disease-resistant breeding and healthy seedling production of sugarcane.[Method]Different samples,collected from Guangxi sugarcane areas,were detected by RT-PCR with SCYLV specific primers P1/P2.A distinct fragment for each SCYLV genotype was amplified by RT-PCR using specific primers of BRA-PER-F/BRA-PER-R,REU-F/B-REVd and CUB-F/CUB-R.[Result]The results of SCYLV RT-PCR detection revealed that 630bp genomic fragments were amplified in fifty-seven samples from a total of 124 samples.Nucleotide sequence of the RT-PCR products was found to be 95％-99％ identical to the sequence of the SCYLV isolates reported in GenBank.The survey of SCYLV results showed that fifty-seven samples were found to be positive by RT-PCR detection from total of 124 samples（infection rate：46.0％）.The sugarcane crop was infected by SCYLV most seriously in northern Guangxi as the detection rate was 76.0％.It was found that 50.0％ sugarcane cultivars were infected by SCYLV in western Guangxi,40.0％ in mid of Guangxi,36.8％ in southern Guangxi,and 16.6％ （the lowest） in eastern Guangxi.The major commercial sugarcane variety of ROC22 was also found to be affected by SCYLV in Liucheng,Yizhou,Qinzhou and Jinguang state farm,which were the major sugarcane areas in Guangxi.The results also showed that the highly susceptible varieties to SCYLV were Liucheng 03-182,GT21,YT55 and YT93-159.The survey of SCYLV genotype results indicated that three virus genotypes including CUB,BRA-PER and REU were identified in Guangxi.Genotypes CUB,BRA-PER,and REU were found 63.2％,56.1％,and 5.3％ of the total samples,respectively.Genotype CUB was found in three big sugarcane growing locations （northern,mid and southern Guangxi）.Genotype BRA-PER was found located in all five big sugarcane producing locations,whereas genotype REU was found distributed in Liuzhou,Pingxiang and Nanning sugarcane producing areas.[Conclusion]SCYLV disease has been developing and spreading in sugarcane areas and three genotypes are found distributed in various degrees in sugarcane locations of Guangxi.