小麦穗部发育多效基因的遗传分析与基因定位

Genetic Analysis and Gene Mapping of the Spike Development Pleiotropic Gene in Wheat

在小麦育种材料中首次发现一种穗部发育萎缩且花器官明显退化,但茎、叶等其他器官发育正常的突变体sda1(spike development atrophy 1)。用显微镜观察突变体sda1的花器官,用碘-碘化钾鉴定其小孢子育性;以‘陕麦94’为父本,突变材料sda1为母本构建F2群体,调查各主要农艺性状,灌浆期测定穗部及穗下茎可溶性糖含量、旗叶光合性能(净光合速率、气孔导度、胞间CO2浓度、蒸腾速率),对该突变体进行遗传分析;利用SSR微卫星标记,通过混合分离分析(BSA)和群体连锁分析进行基因定位,进一步探索该基因功能。结果表明:(1)小麦突变体sda1雄蕊发育畸形,雌蕊发育萎缩,小孢子几乎全部丧失育性。(2)对突变体sda1原株系中表型正常植株的后代分离统计分析结果证明,该突变性状由1对隐性核基因控制,并命名该基因为SDA1。(3)在F2群体中,突变株抽穗期较正常株延迟4d;穗部及穗下茎可溶性糖含量分别显著高于正常株30.6%和11.0%,但突变株与正常株的抽穗持续时间(均为8d)和光合性能无显著差异。(4)经基因定位分析初步确定SDA1位于小麦6B染色体WMC398和BARC136标记之间,与两标记的遗传距离分别为2.2cM和2.1cM。推测认为,SDA1是一个控制抽穗期与器官发育的多效基因,且该基因突变影响植株的糖分转化与利用。

A spike developmental atrophy mutant with deformed flowers （stems, leaves and other organ were developing normally） ,named as sdal ,was first identified from wheat breeding lines. We observed the morphological characteristics of stamen, pistil, and the mierospore stained with IKI under a microscope. For genetic analyses,we generated an Fe population by crossing sdal with ＇Shaanmai 94＇ wild type. We in vestigated the agronomic traits of Fz population,and content of soluble sugar in spike and internode below ear and photosynthetic characteristics of flag leaf at filling stage were measured. By means of bulked segre gation analysis and small populationbased linkage analysis using the published SSR markers we mapped the gene. The results showed that （1）The stamen and pistil developed atrophy and the microspore of sdal was abortion. （2）The original strain of mutant segregation tests suggested that, the mutant phenotype was controlled by a single recessive nuclear gene named as SDA1 （spike development atrophy 1）. （3）The mu tant heading date delayed 4 days comparison with the wild type;and soluble sugar content of internode be low ear and spike in mutant wheat were significantly increased 30.6% and 11.0% than those in normal wheat at filling stages. However, the heading duration was 8 days both the mutant wheat and the normal wheat ;and the photosynthetic characteristics of flag leaf between mutant and normal wheat were not detec