大豆芽黄新突变体vl-1的光合特性与基因定位

Identification and Fine Mapping of A New Virescent Mutant vl-1 in Soybean

为发掘大豆叶色新基因资源,探讨叶绿素合成及光合作用机理,本研究以南农99-6芽黄新突变体vl-1和野生型(WT)品种南农99-6为试验材料,分析突变体与野生型形态、叶绿体结构、色素含量及光合特性,并进行遗传和基因定位研究。结果表明,突变体vl-1幼叶呈黄色,其类胡萝卜素、总叶绿素、叶绿素a、叶绿素b含量均极显著低于野生型,叶绿体内基质片层排列疏松且减少,原片层体居多;突变体vl-1成熟叶片的叶色转绿,其光合色素含量、叶净光合速率、气孔导度、蒸腾速率与野生型均无显著差异,但胞间CO2浓度显著低于野生型。突变体vl-1与2个正常叶色亲本杂交衍生遗传群体叶色分离比例分析表明,芽黄受1对隐性核基因控制。利用科丰1号×突变体vl-1 F2群体将芽黄基因vl1定位于第8号染色体顶端SSR标记BARCSOYSSR_08_0037和BARCSOYSSR_08_0073之间,物理距离为628 kb,该区段未见大豆叶色基因定位的报道,共包含76个预测基因。本研究结果为揭示大豆芽黄的遗传机制奠定了理论基础。

To discover new gene resources of leaf color for studying the mechanism of chlorophyll synthesis and photosynthesis,the soybean seeds of variety Nannong 99-6 were treated by60 Co-γ rays irradiation,and a novel virescent mutant vl-1 with emerging yellowleaveswas identifiedfrom M3 generation. The morphology,chloroplast structure,pigment content and photosynthetic characteristics of mutant vl-1 were investigated,and the inheritance and gene mapping were also studied. Compared with the wild type,the young leaves of mutant vl-1 plants showed significant reduction of photosynthetic pigments,and the structure of chloroplast displayed fuzzier grana,looser stroma lamella and more prolamellar body. The mature leaves of mutant vl-1 turned green and there were no significant difference in the photosynthetic pigment content,net photosynthetic rate,stomatal conductance and transpiration rate between mutant vl-1 and the wild type,but the intercellular CO2 concentration in the mutant was significantly lower than that in the wild type. Genetic analysis suggested that the mutational trait was controlled by a single recessive gene designated as vl1. Using virescent individuals from the F2 population（ KF1 × vl-1）,the target locus vl1 was finally mapped in a 628 kb region on the top of chromosome 8 between SSR marker BARCSOYSSR_ 08_ 0037 and BARCSOYSSR_08_0073,containing 76 annotation genes. This study can make a well foundation for further research on genetic base of leaf color in soybean.