野生花生遗传物质渗入到栽培种的分子证据

Molecular Evidence for Gene Introgression from Wild Species to Cultivated Varieties in Peanut

花生属野生种具有高抗严重影响花生产量的主要病虫害的优良基因,花生区组二倍体野生种A.correntina对锈病、斑驳病毒病、PStV、蓟马、蚜虫、叶蝉、螨虫、玉米螟等多种病虫害也具有抗性。19份由珍珠豆型农家品种贺粤1号与A.correntina经可育性杂交获得三倍体F1代,F1代再经过人工染色体加倍、回交和多代自交选择,形成的能稳定遗传且性状优良的四倍体新品系,4份栽培品种和野生亲本A.correntina共24份材料用于SSR分析,40对SSR引物中有3对引物PM36、PM50、PM305,能在部分杂种后代(PM36:T60;PM50:J17、J20、J22;PM350:J7、S11、T62)中稳定地扩增出野生亲本的特异谱带,表明这些材料整合了野生亲本的遗传物质。SSR特异谱带可以作为这几份材料中野生亲本A.correntina的特异遗传标记。此外,有两对引物PM36、PM106能在一些杂种后代中扩增出父母本没有的DNA条带,使SSR分子标记表现出非共显性。

Wild A rachis germplasm is an ideal source of resistance to fungal or bacterial pathogens, viruses and insect pests. A rachis correntina （2n=20） belong to section A rachis has multiple disease resistance and the triploid F1 plants were polyploidized by colchicine treatment to produce hexaploids. After self-crossing, due to chromosome rearrangments, tetroploid plants occurred and were used for self-crossing or for back-crossing with cultivated parents. Morphological and resistant evaluation proved gene flow from wild species to cultivated peanut. In the present study, 19 hybrid lines, wild and cultivated parents and 3 cultivated varieties were screened for DNA variation and gene introgression by using SSR molecular markers. Among the 40 SSRs screened, 16amplified polymorphic bands and 3 of them （PM36, PM50, PM305） were able to produce bands that specific to A.correntina and the specific bands could be detected in several progenies. The results provided molecular evidence for gene introgression from wild species to cultivated peanut. The result also indicated that DNA fragment pattern was not those for SSR markers, instead there were new bands and several bands were absent in interspecific derivatives. The reason for the non-codominant genetic manner was discussed.