Zhou Weihua's research team made new progress in the study of the mechanism of the formation and regulation of rice secondary wall

secondary wall is the most abundant renewable resources on the earth, natural secondary wall is often produced into a variety of fiber products, serving people's daily life, can also be used as raw materials for the paper industry and bioeneable energy, has important economic value. Secondary wall is the material basis of plant growth, which affects many physiological processes of life activities. For example, the level and quality of secondary wall synthesis in rice are directly related to the important agro-artistic features such as plant height and anti-invertability, so its synthesis is strictly regulated. The study found that a large number of NAC, MYB and other types of transcription factors constitute a complex network to answer various signals inside and outside the plant body, accurate regulation of secondary wall biosynthetic. So far, however, very few negative regulatory factors have been identified. Increase leaf angle1 (ILA1) is our previously reported Raf-like MAPKKK protein, which regulates secondary wall formation, and the mutual protein ILA1 interacting protein4 (IIP4) is its phosphorylated substrate, with unknown biological functions.
The research team of Zhou Weihua of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences created the iip4 mutant using CRISPR/Cas9 gene editing technology, and found that the thickness of the secondary wall of the mutant increased significantly, and the content of cellulose and ligand increased slightly, indicating that IIP4 negatively regulated the synthesis of the secondary wall of rice. A large number of biochemistry and molecular biology studies have found that IIP4 and the top-level key regulatory factors of secondary wall synthesis, NAC29/NAC31, interoperate to inhibit the expression of downstream regulated genes, such as MYB61, CESA4, CESA7, CESA9, thus interfering with secondary wall synthesis. The IIP4 subcellular positioning of ILA1 phosphate is changed and transferred from the nuclei to the cytonite, resulting in the release of the mutual protein NAC29/NAC31 in the nuclei of the cells, thus promoting the expression of downstream genes and secondary wall synthesis. The sequence analysis of IIP4 shows that it has atypical CCC base sequence (C-X4-C-X10-C-X2-H) that repeats regularly. IIP4 isoglobins are widespread and highly conservative in plants, suggesting the importance of their function. The regulatory effect of IIP4 on secondary wall synthesis can also be used to improve crop resistance to inverting. This study analyzes the signal transducting path of ILA1-IIP, which provides an important basis for clarifying the molecular mechanism of rice secondary wall formation and the design and breeding of high-yielding high-quality molecules in crops.
the above findings were published online November 21, 2017 in the journal
(DOI:10.1016/j.molp.2017.11.004). The communication authors of this article are Zhou Weihua Researcher and Zhang Baocai Associate Researcher, the first author is Zhang Dongmei, a Ph.D. graduate of Zhou Weihua Research Group, who provides important help in the creation of mutants. The study was supported by the Natural Science Foundation Project (31125019,31370310), the Chinese Academy of Sciences Pilot Special (XDA08010103-3), the Gm Special (2016ZX08009-003) and the Youth Promotion Association. (Source: Science.com)