一个获得与缺失变异(PAV)调控甜瓜果实苦味  

A Presence-Absence Variation(PAV)Regulates Fruit Bitter in Melon(Cucumis melo L.)

作　　者：李娜[1] 尚建立[1] 周丹[1] 李楠楠[1] 王吉明[1] 马双武[1] LI Na;SHANG Jian-li;ZHOU Dan;LI Nan-nan;WANG Ji-ming;MA Shuang-wu(Zhengzhou Fruit Research Institute,Chinese Academy of Agricultural Sciences,Zhengzhou 450009)

机构地区：[1]中国农业科学院郑州果树研究所,郑州450009

出　　处：《植物遗传资源学报》2020年第2期377-385,共9页Journal of Plant Genetic Resources

基　　金：国家农作物种质资源平台(NICGR2015-016);国家作物种质资源保护和利用专项(2014NWB038);中国农业科学院科技创新工程专项经费项目(CAAS-ASTIP-2018-ZFRI);国家现代农业产业技术体系建设专项(CARS-25)。

摘　　要：甜瓜苦味物质严重影响其口感和品质。本研究利用不苦的薄皮甜瓜品系C69和苦的薄皮甜瓜品系C14构建了一个包含100个单株的F2群体。首先利用2b-RAD测序构建一个遗传连锁图谱。其次,结合群体的苦味性状进行全基因组的QTL定位和关联分析。然后,利用2b-RAD测序特有的技术优势进行群体的获得与缺失变异(PAV)的挖掘。最后,利用亲本的重测序信息确定控制苦味性状的关键基因。结果发现,F1的果实表现出强烈的苦味,F2群体中苦与不苦的单株分别为81个和19个,符合3∶1的分离比(χ^2=1.92,P=0.1659),表型表明所用甜瓜材料的苦味主要是由一个显性的基因位点控制。利用477个SNP标记构建一张包含10个连锁群的连锁图谱,总长为337.79 cM,标记间平均间隔0.71 cM。全基因组QTL定位在8号连锁群(对应9号染色体),检测到一个解释表型变异为20%的甜瓜苦味QTL。全基因组关联分析检测到7个SNPs与苦味性状相关,全部位于9号染色体苦味QTL的基因组区域。通过PAV分型分析仅发现一个特有的大片段缺失(21707702~21743072 bp),位于QTL区域,且在所有的不苦株系中存在,而苦的株系中不存在。基于两个亲本材料的深度重测序信息,发现这个PAV的区域更大,约为62 Kb,共涉及到9个连续的基因(MELO3C005601、MELO3C005602、MELO3C005603、MELO3C005604、MELO3C005605、MELO3C005606、MELO3C005607、MELO3C005608和MELO3C005609),其中5个是细胞色素P450基因。构建的系统发育树表明,这5个细胞色素P450基因与参与葫芦素C/B/E合成的细胞色素P450基因簇CYP81Q58、CYP81Q59和CYP712D8在一个进化枝,可能行使类似的功能,为潜在的类似于黄瓜葫芦素C合成的基因簇的一部分。前人通过比较基因组学研究获得的2个控制葫芦素B合成的bHLH转录因子CmBr(MELO3C005610)和CmBt(MELO3C005611)同在9号染色体,与本研究检测到的PAV紧密挨在一起。我们的研究结果为后续不苦甜瓜�Bitterness in melon(Cucumis melo L.)seriously affects fruit quality and marketability.An F2 segregating population was constructed using 100 individuals derived from a cross between the non-bitterness female parent"C69"and the bitterness male parent"C14".First,a genetic linkage map was constructed based on 2 b-RAD sequencing;second,combined genetic map and phenotypic trait,QTL mapping and genomewide associated analysis were performed;third,PAV detection was analyzed by the in-depth information of 2 b-RAD sequencing;finally,key genes were analyzed by the re-sequencing of two parents.The F1 showed strong bitterness,and 81 and 19 individuals showed bitter and non-bitter,respectively,in F2 population,which indicated a significant fit for 3∶1 ratio(χ^2=1.92,P=0.1659),which suggested that bitter was controlled by one dominant gene in melon line"C14".A linkage map was constructed based on 477 SNPs distributed on 10 linkage groups.The total length of the linkage map was 337.79 cM,with an average distance of 0.71 cM between adjacent markers.Whole genome QTL mapping identified only one QTL for bitterness and explained 20%of the phenotypic variation on LG08(corresponding to chromosome 9).Genome-wide associated analysis detected seven SNPs significantly associated with bitterness in melon,which located on the target QTL region for bitter on chromosome 9.PAV analysis found one novel deletion(from 21707702-21743072 bp on chromosome 9)located on the QTL region and explained the phenotype in all in F2 population.The in-depth re-sequencing of two parents were checked and found the segment of deletion was larger,about 62 Kb,and involved in 9 consecutive annotated genes(MELO3 C005601,MELO3 C005602,MELO3 C005603,MELO3 C005604,MELO3 C005605,MELO3 C005606,MELO3 C005607,MELO3 C005608 and MELO3 C005609).Of the 9 genes,5 encoded CYP450 genes.The constructed phylogenetic tree indicated that these five cytochrome P450 genes may play a similar function with the cytochrome P450 gene clusters CYP81 Q58,CYP81 Q59 and CYP712 D8,which involve

关 键 词：甜瓜 苦味 获得与缺失变异(PAV) 2b-RAD QTL 

分 类 号：S652[农业科学—果树学]