Yan Fan, Githiri Stephen M, Liu Yajing, Sang Yu, Wang Qingyu, Takahashi Ryoji
College of Plant Science, Jilin University, Changchun, China.
Horticulture Department, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
Front Plant Sci. 2020 Jan 31;10:1809. doi: 10.3389/fpls.2019.01809. eCollection 2019.
Pubescence color of soybean is controlled by two genes, and . In the presence of a dominant allele, dominant and recessive alleles of the locus generate tawny and light tawny (or near-gray) pubescence, respectively. Flavones, responsible for pubescence color, are synthesized two copies of flavone synthase II genes ( and ). This study was conducted to map and clone the gene. Genetic and linkage analysis using an F population and F families derived from a cross between a Clark near-isogenic line with light tawny pubescence (genotype: ) and a Harosoy near-isogenic line with tawny pubescence () revealed a single gene for pubescence color around the end of chromosome 3. Genome sequence alignment of plant introductions revealed an association between premature stop codons in Glyma.03G258700 (R2R3 MYB transcription factor) and recessive allele. Cultivars and lines having near-gray or light tawny pubescence and a gray pubescence cultivar with allele had premature stop codons in the gene. These results suggest that Glyma.03G258700 corresponds to the gene. It was predominantly expressed in pubescence. Compared to a tawny pubescence line, a near-isogenic line with allele produced extremely small amounts of transcripts of Glyma.03G258700, and in pubescence. The promoter of and shared -acting regulatory elements for binding of MYB proteins. These results suggest that the wild type of Glyma.03G258700 protein may bind to the promoter of genes and upregulate their expression, resulting in increased flavone content and deeper pubescence color. In contrast, mutated Glyma.03G258700 protein may fail to upregulate the expression of genes, resulting in decreased flavone content and dilute pubescence color.
大豆茸毛色由两个基因(T)和(t)控制。在存在显性(T)等位基因的情况下，(t)位点的显性和隐性等位基因分别产生黄褐色和浅黄褐色（或近灰色）茸毛。负责茸毛色的黄酮由黄酮合酶II基因(FNSII - I)和(FNSII - II)的两个拷贝合成。本研究旨在定位和克隆(t)基因。利用一个(F_{2})群体以及由浅黄褐色茸毛的Clark近等基因系（基因型：(tt)）与黄褐色茸毛的Harosoy近等基因系（(TT)）杂交衍生的(F_{2:3})家系进行遗传和连锁分析，结果表明在3号染色体末端附近存在一个控制茸毛色的单基因。对植物引进品种的基因组序列比对发现，在Glyma.03G258700（R2R3 MYB转录因子）中存在的提前终止密码子与隐性(t)等位基因之间存在关联。具有近灰色或浅黄褐色茸毛的品种和品系以及具有(t)等位基因的灰色茸毛品种在该基因中都有提前终止密码子。这些结果表明Glyma.03G258700对应于(t)基因。它在茸毛中大量表达。与黄褐色茸毛品系相比，具有(t)等位基因的近等基因系在茸毛中产生的Glyma.03G258700、(FNSII - I)和(FNSII - II)转录本极少。(FNSII - I)和(FNSII - II)的启动子具有用于MYB蛋白结合的顺式作用调控元件。这些结果表明，野生型Glyma.03G258700蛋白可能与(FNSII)基因的启动子结合并上调其表达，从而导致黄酮含量增加和茸毛色加深。相反，突变的Glyma.03G258700蛋白可能无法上调(FNSII)基因的表达，导致黄酮含量降低和茸毛色变浅。
