BMC Plant Biology:农科院作科所夏先春研究组解析小麦面粉颜色遗传

近日，国际学术BMC系列旗舰刊物《BMC Plant Biology》杂志在线发表了中国农业科学院作物科学研究所小麦亲本创制与新品种选育创新团队夏先春研究员和何中虎研究员合作的题为“Genetic analysis of phytoene synthase 1 (Psy1) gene function and regulation in common wheat”的研究论文，研究通过对小麦籽粒黄色素合成途径的研究，揭示了Psy1调控面粉颜色的分子机制。作科所博士研究生翟胜男为本论文第一作者，夏先春研究员和何中虎研究员为共同通讯作者。

随着生活水平的提高，消费者对面粉及面制品的品质提出更高要求，面粉颜色性状已成为小麦品质评价及遗传改良的重要内容。类胡萝卜素是其小麦籽粒中黄色素的主要组分，也是影响面粉颜色的主要因素。创新团队前期研究表明，八氢番茄红素合酶(PSY)是类胡萝卜素合成途径的关键酶，小麦八氢番茄红素合成基因Psy1是影响面粉颜色的主效基因。然而，Psy1调控面粉颜色形成的分子机制却少有报道。

研究人员利用RNAi、rna-seq及TILLING相结合的试验策略，对Psy1调控面粉颜色的分子机制进行探索。RNAi转基因植株籽粒Psy1表达降低54–76%，黄色素含量下降26–35%，证明Psy1对小麦籽粒黄色素合成具有重要影响。次级代谢途径和核心代谢途径上的45个候选基因构成复杂的调控网络，协同响应Psy1表达下调。天冬氨酸富集区(DXXXD)是PSY1重要功能结构域，其附近保守核苷酸通过调控基因表达、酶活性及选择性剪接等方式影响黄色素合成。花后14天是小麦籽粒Psy1表达调控的关键时期。该研究成果对小麦品质改良具有重要意义。

原文链接:

genetic analysis of phytoene synthase 1 (Psy1) gene function and regulation in common wheat

原文摘要:

Background

Phytoene synthase 1 (PSY1) is the most important regulatory enzyme in carotenoid biosynthesis, whereas its function is hardly known in common wheat. The aims of the present study were to investigate Psy1 function and genetic regulation using reverse genetics approaches.

Results

Transcript levels of Psy1 in RNAi transgenic lines were decreased by 54–76 % and yellow pigment content (YPC) was reduced by 26–35 % compared with controls, confirming the impact of Psy1 on carotenoid accumulation. A series of candidate genes involved in secondary metabolic pathways and core metabolic processes responded to Psy1 down-regulation. The aspartate rich domain (DXXXD) was important for PSY1 function, and conserved nucleotides adjacent to the domain influenced YPC by regulating gene expression, enzyme activity or alternative splicing. Compensatory responses analysis indicated that three Psy1 homoeologs may be coordinately regulated under normal conditions, but separately regulated under stress. The period 14 days post anthesis (DPA) was found to be a key regulation node during grain development.

Conclusion

The findings define key aspects of flour color regulation in wheat and facilitate the GENEtic improvement of wheat quality targeting color/nutritional specifications required for specific end products.

DOI: 10.1186/s12870-016-0916-z

作者：夏先春