胡萝卜素调控,硬质胚乳 z-bo 2020-10-23 382

　　Recently, the research team of Wu Young-Louis, a researcher at the Center for Excellence in Molecular and Plant Sciences of the Chinese Academy of Sciences, published a paper that affected the carotenoid-modulated core texture of the maze by affecting the integrity of the Mylosten envelope by nature communication . This is the first study to clone a major QTL from a natural population. This QTL controls the formation of cornhard/mayendsperm-Ven1 (Vitreousendosperm1), and the allelic variant of this gene is the carotenoid of Cornendosperm. I found that the content of polar groups and non-polar groups can be adjusted. The increase of non-polar carotene slows down the decomposition of amyloid membrane and interferes with the interaction of protein and starch granules, thereby affecting the formation of hard endoderm cells.

　　Hard corn kernels/May grains are a pair of important agricultural characteristics that affect the harvest, storage, transportation and food processing of corn. The formation of hard endoderm cells depends on the close interaction between protein bodies (gliadin storage) and amyloid bodies. During the development of maize endometrium, the protein bodies in the extra-endometrial area are dense, with small starch granules, while the protein bodies in the central area are sparse and starch particles are large. As the grain matures and dehydrates, the protein bodies in the outer region of the endometrium and other intracellular contents (such as cytoplasm, organelles and cytoskeleton) are entangled with each other to form a protein matrix that firmly holds starch granules. The package forms a dense, hard endoderm; the central area of the endometrium leaves lacks protein bodies, which completely exposes starch granules and forms loose powdery endoplasmic follicles. The hard phenotype of the endometrium of corn has abundant changes in the natural population, from almost completely blunt material to completely blunt material, but the academic circles lack understanding of QTL and the molecular mechanism controlling its formation. Carotenoids are mainly concentrated in the hard endoderm. Their composition and content determine the color of most corn varieties (from white to orange-red; purple corn is due to the accumulation of anthocyanins in the aleurone layer. Will be triggered). In natural populations, the carotenoid content varies greatly, but the upper alleles that can be used for biological enhancement of vitamin A vary slightly. In the breeding process, the color of the grain and the quality of the hard powder are obviously artificially selected, but in academia, the internal connection between the two is still unclear. In the context of A619, the researchers used the conventional hard cone incompatibility W64A and the silty corn incompatibility A619 through eight consecutive backcrossings, namely the hard and silty homologous gene lineage NILW64A. And built NILA 619. Through BSA sequencing, detailed localization and RNAi gene verification, the main QTL Ven1 that affects the formation of hard sperm has been cloned. This gene encodes β-carotene hydroxylase 3 (β-carotene hydroxylase 3, HYD3). It is highly expressed in endometrial starch cells, and the protein is located inside the amyloid membrane. Ven1 is fragmented in NILA619 and its expression is low, so β-carotene will not be hydroxylated to downstream polar carotene, and the content of other upstream non-polar carotene will increase. This changes the physicochemical properties of amyloid membranes. The amyloid film of ILA619 (including starch granules) has enhanced stability and irregular swelling, which delays its degradation during the interaction between the internal sperm cells and the interaction between the protein body and the starch granules and protein. The formation of the matrix grid is hindered. When mature, a powdery endoderm is formed. On the contrary, the hard, nearly homogeneous gene line NILW64A has high Ven1 expression, reduced non-polar carotenoid content, regular amyloid membrane morphology and easy degradation, and the surface of starch granules has concentrated protein and cytoplasm. Form a dense protein matrix. The grid surrounds the structure. This is an important basis for the formation of hard endoderm cells. In order to prove that the excessive accumulation of non-polar carotene is the cause of the silty phenotype of A619, the researchers conducted extensive EMS mutagenesis in A619 to block the upstream carotenoid synthesis pathway. I got a variant material. The common feature is: from powdered endometrium to hard endometrium, it is called Ven1 inhibitor (Ven1A619, Ves inhibitor). GWAS analysis showed that there are multiple Ven1 modifiers in the natural population. That is, it forms hard endoderm cells without changing the carotene composition. This study reveals a new molecular genetic mechanism through which carotenoids affect the formation of hard endoderm cells by affecting the stability of amyloid membranes. This is useful for growing hard corn varieties with high carotene.

　　Associate Researcher Wang Haihai and Postdoctoral Researcher Huang Yongcai of the Center for Molecular Plant Excellence are the co-lead authors of this article, and Wu Yongrui is the corresponding author of this article. Doctoral students Xiao Qiao, Huang Xing, post-doctoral researcher Li Changsheng, Xiang Xiaoli, assistant researcher Wang Qiong, master student Zhu Yidong, associate researcher Wang Jiechen, public technical service center teacher Gao Xiaoyan, associate professor Wang Wenqin of Shanghai Jiaotong University and Ferron Bryan from the University of Arizona A. Larkins participated in this study. The research work was supported by the Science and Technology Program led by the Ministry of Science and Technology, the National Natural Science Foundation of China and the Chinese Academy of Sciences.