Researchers Discover the Link between Ethylene Regulation of Growth and Cell Wall Establishment

Research teams led by Prof. ZHANG Jinsong and Prof. ZHOU Yihua from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences revealed that ethylene inhibition of root growth depends on CELLULOSE SYNTHASE-LIKE C proteins-mediated xyloglucan (XyG) induction in cell wall of rice. The study was published in The Plant Cell on June 29, 2024 (https://doi.org/10.1093/plcell/koae195).

Phytohormone ethylene participates in multiple aspects of plant. How does ethylene regulate plant growth? Although the processes of ethylene signaling pathway and signaling regulation are currently almost clear, the understanding of where ethylene signal is outputted downstream for growth regulation is still limited, especially in crops, such as rice.

Plant cells are encased in a cell wall which determines the morphogenesis of plant cells and the plastic growth for plant. The cell wall consists of macromolecular polysaccharides, highly glycosylated proteins, and lignin, forming a complex and dynamic polysaccharide network. Is there a relevance between ethylene regulation of plant growth and cell wall establishment?

The changes in cell shape, cell wall thickness, cell wall components and gene expression drew the attention of the researchers in cell wall synthesis during ethylene inhibition of root growth. The overexpression, mutant, and genetics analyses supported that OsCSLC2-mediated and ETHYLENE-INSENSITIVE3-LIKE1 (OsEIL1)-regulated XyG accumulation in the epidermal cell walls of root elongation and differentiation zone is indispensable for the ethylene inhibition. After several experiments, the researchers finally observed a stronger phenotype of root ethylene response using higher-order mutants of CSLC gene family. Another issue regarding the interaction between XyG and cellulose remains a challenging aspect that requires further research.

Together, this published study revealed that ethylene induces XyG and cellulose accumulation in root cell walls by upregulating the expression of OsCSLC1, 2, 7, 9, 10 and CELLULOSE SYNTHASE A3, 4, 7, 9 in an OsEIL1 and auxin pathway-dependent manner.

These findings link plant hormone signaling with cell wall establishment, broadening the understanding of root plastic growth in rice and other crops.

 

Contact:

Dr. ZHOU Yang, Prof. ZHOU Yihua, Prof. ZHANG Jinsong

Institute of Genetics and Developmental Biology, Chinese Academy of Sciences