柑橘果实大小与质量的遗传分析和数量性状位点定位

Genetic analysis and quantitative trait locus mapping of citrus fruit size and mass

为探究柑橘果实大小与质量的遗传调控机制,开展了果实大小和质量的数量性状位点(quantitative trait locus,QTL)定位分析,以挖掘调控基因。以‘晚蜜2号’和‘梨橙2号’的94株F1代材料为分离群体,采用保守同源序列(conserved ortholog sequence,COS)和微卫星标记即简单重复序列(simple sequence repeat,SSR)构建遗传连锁图谱,测定单株成熟果实大小和质量等性状,并进行遗传传递力分析和QTL定位分析。结果表明:本研究构建了一张包含201个标记、10个连锁群,总长为1194.5 cM的柑橘遗传连锁图谱;定位到与果实质量相关的4个QTLs,与横径相关的3个QTLs,与纵径相关的4个QTLs,都分别位于WL3和WL8连锁群上。通过对这些区域内的编码基因进行挖掘,发现了一些与果实发育相关的候选基因:GATA转录因子、生长素响应因子(auxin response factor,ARF)和GDSL酯酶。本研究鉴定到的QTLs和候选基因可为柑橘果实大小和质量的遗传研究、育种和物种改良提供理论参考和分子标记工具。

In order to explore the genetic regulation mechanism of citrus fruit size and mass,mapping analysis of quantitative trait loci(QTLs)of fruit size and mass was carried out to find regulatory genes.The segregating population in this study was the F1 generation with a total of 94 plants,from the cross of‘Wanmi 2’[Citrus unshiu(Mark.)Marc.×C.sinensis(L.)Osb.]and a local sweet orange cultivar‘Licheng 2’[C.sinensis(L.)Osb.].Conserved ortholog sequence(COS)and simple sequence repeat(SSR)markers were used to construct a genetic linkage map of the segregating population.Fruit size and mass were measured at the full maturing stage.Genetic transmitting ability analysis and QTL mapping were carried out.The results showed that this study constructed a genetic linkage map,which contained 201 markers,10 linkage groups,with a total length of 1194.5 cM.Four QTLs related to citrus fruit mass,three QTLs related to citrus transverse diameter,and four QTLs related to citrus longitudinal diameter were detected.All the QTLs were distributed on WL3 and WL8 linkage groups.A batch of functional genes(GATA transcription factor,auxin response factor and GDSL esterase)related to the development of citrus fruits were identified according to the functional annotations of the genes in the genome defined by the markers.The QTLs located and the candidate genes identified in this study will be helpful for citrus breeding and theoretical research.