杜邦先锋解析小麦育性基因Ms26

      杂种优势的利用是作物增产的最重要手段，而不育系材料是各大种子公司的核心育种资源。最近，杜邦先锋公司对小麦中一个控制育性的基因进行了详细的功能研究。

      玉米、水稻、大豆等作物中的Ms26/CYP704B基因在花粉发育过程中起到了重要的作用，它通过参与孢粉素的生物合成途径形成花粉外孢壁。为了研究该基因在面包小麦中功能，研究人员突变了A、B、D三个同源基因组上的Ms26基因。结果显示，单或双突变都不会影响小麦的育性，只有将三个基因组上的Ms26基因全部突变时，小麦的花药和花粉才会发育异常，从而表现出完全的雄性不育性状。此外，双同源和一个异源的突变可以导致部分不育。互补试验表明，转入两个玉米和水稻来源的Ms26基因就可以恢复不育株的育性，而一个玉米Ms26基因却不行。
      小麦中Ms26/CYP704B基因的功能深化了我们对麦类作物雄性不育机制的理解。针对该基因的遗传操作能够创制更多的不育系材料，提高小麦育种水平。
 
PLoS One, 12 (5): e0177632; 2017 May 16
MS26/CYP704B is required for anther and pollen wall development in bread wheat (Triticumaestivum L.) and combining mutations in all three homeologs causes male sterility.
Author
Singh M, Kumar M, ThilgesK, Cho MJ, Cigan AM.
DuPont Pioneer, USA.
Abstract
Development of anthers and pollen represents an important aspect of the life cycle in flowering plants. Genes contributing to anther and pollen development have been widely studied in many plant species. Ms26/CYP704B genes play an important role in pollen development through biosynthesis of sporopollenin for pollen exine formation. To investigate the role of Ms26/CYP704B genes in anther and pollen development of bread wheat, mutations in the A-, B-, and D-homeologs of the putative Ms26/CYP704B gene were analyzed. Single and double homozygous mutants in any of the homeologs did not affect pollen development and male fertility. Triple homozygous mutants resulted in completely male sterile plants that were defective in pollen and anther development. Additionally, double homozygous-single heterozygous mutants were also male sterile although with varying levels of residual fertility. The fertility of these triple mutants was dependent upon the homeolog contributing the wild-type allele. Two heterologous Ms26/CYP704B genes, when transformed into a triple homozygous mutant background, completely restored male fertility, whereas a single gene was unable to restore fertility. Functional analysis of Ms26/CYP704B furthers the understanding of male fertility genes which can be utilized for the development of novel hybrid seed production systems in wheat.