| Pepper(Capicum spp.)is an important vegetable and condiment in our country,and it is widely cultivated in the world.Cucumber mosaic virus(Cucumber Mosaic Virus,CMV)is the main virus that causes pepper’s Virus disease,and it has great harmful to pepper.CMV spread widely and fast,and it is difficult to control by chemical agent,so the breeding of pepper varieties resistant to CMV can effectively reduce the disease.While molecular marker assisted breeding can overcome the defects of traditional breeding and accelerate the breeding process.This paper is based on the publication of the pepper genome data and has taken the high throughput sequencing of SLAF-seq technology as the studying on the basis of molecular breeding.In this paper,the following three aspects were mainly studied:Two pepper inbred lines,C.frutescens cv.PBC688 and C.annuum cv.G29,were used as parental lines and to construct the F1 and F2 populations to verify the phenotype;SLAF-seq technology was used to position the related regions of resistance to CMV;That Indel Markers were used for constructing linkage map resistant to CMV and for QTL mapping was used to predict the related genes resistant to CMV.The main conclusions are as follows:(1)The incidence was calculated including the groups of PBC688 and G29 and their F1、F2.The results showed the disease index(DI)of PBC688 was less than that of G29,while Fi generation plants DI is greater than that of PBC688,and less than that of G29,which indicated that the allele of resistance to CMV in PBC688 was not completely dominant.That the disease levels changed continuously in F2 groups in the autumn of 2013 and 2014 showed the resistance to CMV in PBC688 is quantitatively inherited.(2)745 isolated F2 plants were constructed and inoculated CMV so as to identify individual plant resistance.According to the identified results,we first constructed the resistant and susceptible pools by selecting 10%individuals,then,we did the SLAF library and developed 37077 polymorphic SLAF labels,and last,by using the SNP-index tag correlation analysis,we positioned two related areas locating in chromosome No.2 and chromosome No.11 between the resistant and susceptible pools,associated area size for 4.36 Mb and 3.90Mb,respectively.(3)Indel Markers were developed in associated areas of the chromosome No.2 and chromosome No.11.One resistant to CMV main QTL positioned in associated areas of chromosome No.2 by classical QTL mapping method was named for qcmv2.1,which located in Indel-2-134-Indel-2-151(peak marker for Indel-2-140)with physical map distance for 152.87-153.20 MB(330 KB),the genetic distance of 0.6 cm,a LOD value for 18.36 and the explained phenotypic variation rate of 51.6%.Two minor QTLs were verified in the associated areas of chromosome No.11,named for qcmv11.1 and qcm11.2,which located in Indel-11-31-Indel-11-73(peak marker for Indel-11-64 and Indel-11-66)with physical map distance for 22.07-23.19 MB(1.12 Mb),the genetic distance of 2.7 cm,LOD values for 3.95 and 3.04 and the explained phenotypic variation rate of 8.9%and 7.0%,respectively.Based on the genome sequence of pepper,two candidate genes CA02g19570 and CA02g19600 were identified in chromosome No.2 in 330 KB region.The BLAST results showed that the two candidate genes were homologous with N gene resistant to TMV in potatoes,tomatoes and tobacco,and the two candidate genes have a typical TIR-NBS-LRR resistance gene structure by protein structure analysis,belonging to the NBS-LRR resistance gene family in plants.The above results preliminary showed that CA02g19570 and CA02g19600 genes are the main source of resistance to CMV of hot pepper PBC688. |
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