绿豆遗传连锁图谱的整合

Integration of Mungbean(Vigna radiata) Genetic Linkage Map

利用绿豆及其近缘种的701对SSR引物,对现有绿豆遗传连锁图谱进行补充,结果在高感豆象绿豆栽培种Berken和高抗豆象绿豆野生种ACC41两亲本间筛选到多态性SSR引物104对。群体分析后,结合其他分子数据,使用作图软件Mapmaker/Exp 3.0b,获得一张含有179个遗传标记和12个连锁群,总长1831.8cM、平均图距10.2cM的新遗传连锁图谱,包括97个SSR标记,91个来自绿豆近缘种;RFLP标记76个;RAPD标记4个;STS标记2个。对32个绿豆、小豆共用SSR标记在遗传连锁图谱的分布分析发现,二个基因组间有一定程度的同源性,共用标记在连锁群上的排列顺序基本上一致,只有部分标记显示绿豆和小豆基因组在进化过程中发生了染色体重排;利用新图谱对ACC41的抗绿豆象主效基因重新定位,仍定位于I(9)连锁群,与其相邻分子标记的距离均小于8cM,其中与右翼SSR标记C220的距离约2.7cM。与原图谱比较,新定位的抗性基因与其相邻标记的连锁更加紧密。

A high-density genetic linkage map with informative markers is essential for plant genome analysis,including gene mapping,identification of quantitative trait loci（QTL）,map-based cloning,and physical map construction.A genetic linkage map of mungbean（Vigna radiata,2n=2x=22） was constructed using recombinant inbred line（RIL） population derived from an intersubspecific cross between a highly bruchid-susceptible cultivar Berken and a highly bruchid-resistant wild type ACC41（V.radiata subsp.sublobata）.A total of 104 pairs of polymorphic SSR primers were screened from 701 pairs of primers for density-enhancement of the previous map.In combination with data from other markers,a new genetic linkage map with 179 markers was obtained using Mapmaker/Exp 3.0b software,including 97 SSR markers（91 markers from mungbean close relatives）,76 RFLP markers,four RAPD markers,and two STS markers.All of these marker loci were assigned to 12 linkage groups with total length of 1 831.8 cM and an average marker interval of 10.2 cM.The transferability of SSR markers from the relatives of mungbean was also evaluated in mungbean,including adzuki bean（V.angularis L.）,black gram（V.mungo L.）,common bean（Phaseolus vulgaris）,and cowpea（V.unguiculata）.In the 597 pairs of SSR primers,approximately 65% form adzuki bean,72% from black gram,42% from common bean,and 30% from cowpea could be effectively amplified in mungbean genome,indicating different levels of genomic homology between mungbean and these four relative species.A total of 98 pairs of polymorphic SSR primers from the relative species were effective in genetic analysis of mungbean.The new linkage map of mungbean was compared with a published linkage map of Azuki bean（V.angularis,2n=2x=22,n=11） on the basis of 32 common SSR markers.Most of markers distributed on both maps in similar sequences,except that a few markers rearranged on chromosomes during evolution.In the new map of mungbean,the major gene resistant to bruchid was located on LG I（9） as earlier reported.The distances between this gene and its flanking markers C78（left） and C220（right） were 8.0 cM and 2.7 cM,respectively.Consequently,the marker interval containing this target gene has shortened compared with the previous map and the accuracy has also been improved.