| Sugarcane is the most important sugar crop in the China.Virus disease is the main factor affecting sugarcane production.Baculovirus disease of sugarcane is an important virus disease of sugarcane,which is caused by sugarcane bacilliform virus(SCBV).SCBV belongs to the Badnavirus genus of Caulimoviridae family.When SCBV infects sugarcane,it will affect the stem weight,juice yieldand sucrose content of sugarcane,and finally reduce the yield and quality of sugarcane.The spread of SCBV in sugarcane areas of China is very fast,and the infection rate of SCBV is increasing.In order to clarify the situation of sugarcane infected by SCBV in sugarcane region of China,understand the existing strains and distribution of SCBV in sugarcane region of China,and reveal the genetic diversity,population genetic structure and molecular evolution mechanism of SCBV isolates in China.In this study,747 sugarcane samples were collected from 13 sugarcane regions in China,and SCBV infection rates were detected by PCR.The genetic diversity of SCBV isolates from sugarcane regions in China was analyzed to identify the existing genotypes of SCBV in sugarcane regions,identify new pathogenic genotypes,and analyze the distribution of SCBV genotypes in sugarcane regions.Then RT/RNase H region was selected.Some SCBV isolates with large differences in domain nucleotide sequences cloned their whole genome sequence,and analyzed the genome sequence by bioinformatics such as gene structure,genetic recombination and phylogenetic evolution.The results are as follows:747 sugarcane samples were collected from 13 sugarcane areas in the main sugarcane producing areas of Guangxi,Yunnan,Hainan and Guangdong,and SCBV PCR was performed on these samples using primers SCBV-F and SCBV-R.529 samples were positive.The average detection rate was 70.83%.It can be seen that sugarcane in China is seriously infected by SCBV.SCBV has become an important potential threat to the safe production of sugarcane industry in China.The RT/RNase H region of 477 sugarcane samples from China was cloned and sequenced.After eliminating the same sequence,95 different RT/RNaseH sequences of SCBV were obtained and their phylogenetic trees were constructed.It was found that the SCBV sequence can be divided into 21 genotypes,SCBV-A to SCBV-U.Among them,SCBV-S,SCBV-T and SCBV-U are newly discovered genotypes.It was found that there were 12 SCBV genotypes in China’s sugarcane area,including SCBV-A,SCBV-B,SCBV-C,SCBV-H,SCBV-L,SCBV-M,SCBV-N,SCBV-Q,SCBV-R,SCBV-S,SCBV-T and SCBV-U.Among them,SCBV-T is the main genotype in sugarcane region of China,accounting for 78.3%,followed by SCBV-R genotype,accounting for 3.40%,SCBV-B genotype is the least,accounting for 0.26%.In addition,mixed infection was found in the same sugarcane sample.There are 9 SCBV genotypes in Guangxi sugarcane area;In Yunnan sugarcane area,There are 6 SCBV genotypes;5 SCBV genotypes exist in Guangdong sugarcane area and there are two SCBV genotypes in the Hainan sugarcane area.A complete genome sequence SCBV-YG40 of SCBV isolate was cloned from the sugarcane variety Yuegan 40,with a length of 7790 bp.Consistency analysis between SCBV-YG40 and the reported sequence of 12 reported SCBV isolates showed that SCBVYG40 had the highest nucleotide consistency with SCBV-BO91 isolate in Indian at 82.15%at the genome level,and the lowest nucleotide consistency with SCBGDV-Batavia isolate in French at 48.55%.At the RT/RNaseH sequence level,SCBV-YG40 had the highest nucleotide consistency with Australian SCBIMV-QLD isolate,which was 87.32%.Therefore,SCBV-YG40 belongs to SCBIMV.In genotype,SCBV-YG40 belongs to SCBV-Q genotype.The results of this study further enriched the molecular biology information of genetic diversity of SCBV,and provided the basis for scientific prevention and control of sugarcane baculovirus disease in China.This is not only important for the development of the discipline,but also of great practical significance for the development of sugarcane production and economic construction in China. |
PDF Full Text Request