纽荷尔脐橙对建阳橘柚上柑橘衰退病毒分离株构成的影响

建阳橘柚兼具橘和柚的优良性状,为了解其携带的柑橘衰退病毒(CTV)分离株的分子特征及其传播到江西赣州对赣南脐橙产业的影响,将建阳橘柚(Citrus paradisi×C.reticulata)CTV分离株JY-5嫁接接种到赣南脐橙纽荷尔(C.sinensis)品种上,比较接种前后病毒外壳蛋白(cp)基因的HinfⅠRFLP和SSCP变化情况,实验结果表明,建阳橘柚上CTV分离株RFLP组群由接种前的单一组群变为混合组群,SSCP谱带数增加,在建阳橘柚上受抑制的CTV分离株在纽荷尔脐橙上能得到较好地增殖;同时接种前后分离株cp,p23和k17基因片段序列同源性及聚类分析表明,在建阳橘柚上的CTV分离株JY-5与其嫁接接种在纽荷尔脐橙上的JY-5R分离株并未在系统进化树上聚类在一起,表明两者不具有紧密的亲缘关系,结合RFLP和SSCP分析结果推测,JY-5R可能是在建阳橘柚上受抑制的分离株在纽荷尔脐橙上恢复了增殖。研究结果提示,建阳橘柚上的CTV分离株一旦传到赣南脐橙上,对赣南脐橙产业会带来一定的威胁。

Influence of Newhall Navel Orange on Composition of Citrus tristeza virus Isolates Collected from Jianyang Tangelo

In order to find the potential influence of Citrus tristeza virus(CTV) isolates in Jianyang Tangelo on Gannan navel orange,the CTV isolates were characterized at the molecular level.Jianyang Tangelo(Citrus paradisi × C.reticulata) is a new citrus hybrid cultivar with excellent quality.CTV isolate JY-5 was inoculated in Newhall navel orange(C.sinensis) and the HinfⅠrestriction fragment length polymorphism(RFLP) and single-strand conformation polymorphism(SSCP) of its coat protein(cp) gene was comparatively analyzed.The results of RFLP analysis revealed that the single group of the CTV isolate in Jianyang Tangelo changed into mixed groups when it inoculated in Newhall navel orange.DNA bands of cp/SSCP of CTV isolates increased when the CTV isolate was graft inoculated from Jianyang Tangelo to Newhall navel orange.The results of HinfⅠRFLP and SSCP showed that the replication of some composition of CTV isolate was inhibited in Jianyang Tangelo but enhanced in Newhall navel orange.By analyzing and comparing the nucleotide and amino acid sequences of cp,p23 and k17 of isolate JY-5 in Jianyang Tangelo and isolate JY-5R from inoculated Newhall navel orange,the identity of genomic regions were 92.5%,90.3% and 82.3%,respectively,and of their amion acid sequences were 95.9%,90.9% and 77.9%,respectively.Phylogenetic analysis revealed that the isolate JY-5 in Jianyang Tangelo and JY-5R in inoculated Newhall classified into different clusters in phylogenetic trees of cp,p23 and k17.Sequence comparisons and phylogenetic analysis indicated that no high homology and closer relationships between the isolates JY-5 and JY-5R,the isolate JY-5R was inhibited in Jianyang Tangelo but enhanced in Newhall navel orange.The results suggest that if the CTV isolate from Jianyang Tangelo infects Gannan’s Newhall navel orange and spreads in Ganzhou,maybe cause some damage to Gannan’s navel oranges.Therefore,it is necessary to take a survey on the CTV occurence and Jianyang Tangelo plantation in Ganzhou.