MAPK级联信号调节内皮层细胞壁次生的分子机制

The endodermis around plant root vascular is an important barrier between inner and outside of vascular. The casparian strip and suberin on the endodermis cell wall formed by endodermis secondary growth play important roles in resisting abiotic stresses, regulating nutrient absorption, and defensing against pathogen and pest. We found that the loss function of important MAPK members, MKK4/MKK5 and MPK3/MPK6, result the formation-defect of casparian strip and suberin, suggesting that MAPKs play important roles in endodermis secondary growth. At present, little is known about the signal pathway regulating the endodermis secondary growth. MAPKs were also rarely reported in the field of cell wall modification and secondary growth. Therefore, it is important to study the signal transduction mechanism of MAPKs regulating endodermis secondary growth. This project is going to be focused on MKK4/MKK5 and MPK3/MKK6 to explore the upstream signal and downstream regulation mechanism of MAPKs in this process, in order to elucidate the signal transduction pathway that regulates endodermis secondary growth. In view of the high conservation of MAPKs, this study will provide an important theoretical reference for the improvement of environmental adaptability of different crops.

植物根系维管外围的由内皮层细胞壁次生形成的凯氏带和木栓质结构是隔离维管和外界的重要屏障, 对植物抵抗有毒物质、干旱、盐碱等非生物胁迫, 调节营养吸收以及防御病害等过程至关重要。我们发现MAPK激酶的重要成员MKK4/MKK5和MPK3/MPK6功能缺失导致凯氏带和木栓质形成缺陷, 表明MAPK对内皮层细胞壁次生起重要作用。目前调控内皮层细胞壁次生的信号转导机制知之甚少, MAPK在细胞壁修饰和次生生长领域也鲜见报道, 因此研究MAPK调控内皮层细胞壁次生的信号转导具有重要的科学意义与应用前景。本项目拟以MKK4/MKK5和MPK3/MPK6为重点, 探索MAPK调控内皮层细胞壁次生的生物学功能, 阐明MAPK在该过程中的上游信号和下游调控机制, 以期通过MAPK揭开调控内皮层细胞壁次生的信号转导机制。由于MAPK高度保守, 该研究将为不同作物的环境适应性特征改良提供重要的理论依据。

植物根系维管外围的由内皮层细胞壁次生形成的凯氏带和木栓质结构是隔离维管和外界的重要屏障, 对植物抵抗重金属等有毒物质、干旱、盐碱等非生物胁迫, 调节营养吸收以及防御病害等过程至关重要。.本研究发现MAPK激酶的重要成员MKK4/MKK5和MPK3/MPK6功能缺失导致内皮层木栓质形成缺陷, 表明MAPK对内皮层细胞壁次生起重要作用。目前调控内皮层细胞壁次生的信号转导机制知之甚少, MAPK在细胞壁修饰和次生生长领域也鲜见报道, 因此研究MAPK调控内皮层细胞壁次生的信号转导具有重要的科学意义与应用前景。.本研究以MKK4/MKK5和MPK3/MPK6为重点, 探索MAPK调控内皮层细胞壁次生的生物学功能, 阐明MAPK在该过程中的上游信号和下游调控机制。发现MKK4/MKK5-MPK3/MPK6受到CIF1/CIF2-GSO1/GSO2特定信号的激活，进而调节木栓质合成过程。MKK4/MKK5-MPK3/MPK6功能缺失导致内皮层木栓质合成关键基因的表达下调。同时发现MAPK调控的木栓质合成对于防御重金属胁迫非常关键。植物受到重金属胁迫时，重金属能够激活MAPK进而上调木栓质的合成和累积，进而防御重金属胁迫。由于MAPK高度保守, 该研究将为不同作物的环境适应性特征改良提供重要的理论依据。另外本研究还发现一个潜在的MAPK底物转录因子WRKY71，该转录因子也参与内皮层木栓质的合成调控，具体的分子机制还有待进一步研究。