Zhang Tian-Qi, Lian Heng, Tang Hongbo, Dolezal Karel, Zhou Chuan-Miao, Yu Sha, Chen Juan-Hua, Chen Qi, Liu Hongtao, Ljung Karin, Wang Jia-Wei
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai 200032, People's Republic of China University of the Chinese Academy of Sciences, Shanghai 200032, People's Republic of China.
National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Shanghai 200032, People's Republic of China.
Plant Cell. 2015 Feb;27(2):349-60. doi: 10.1105/tpc.114.135186. Epub 2015 Feb 3.
Plant cells are totipotent and competent to regenerate from differentiated organs. It has been shown that two phytohormones, auxin and cytokinin, play critical roles within this process. As in animals, the regenerative capacity declines with age in plants, but the molecular basis for this phenomenon remains elusive. Here, we demonstrate that an age-regulated microRNA, miR156, regulates shoot regenerative capacity. As a plant ages, the gradual increase in miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) transcription factors leads to the progressive decline in shoot regenerative capacity. In old plants, SPL reduces shoot regenerative capacity by attenuating the cytokinin response through binding with the B-type ARABIDOPSIS RESPONSE REGULATORs, which encode the transcriptional activators in the cytokinin signaling pathway. Consistently, the increased amount of exogenous cytokinin complements the reduced shoot regenerative capacity in old plants. Therefore, the recruitment of age cues in response to cytokinin contributes to shoot regenerative competence.
植物细胞具有全能性，能够从分化的器官再生。研究表明，两种植物激素，生长素和细胞分裂素，在这个过程中发挥关键作用。与动物一样，植物的再生能力会随着年龄的增长而下降，但这种现象的分子基础仍然难以捉摸。在这里，我们证明了一种受年龄调控的微小RNA，miR156，调节芽再生能力。随着植物年龄的增长，miR156靶向的SQUAMOSA启动子结合蛋白样（SPL）转录因子逐渐增加，导致芽再生能力逐渐下降。在老植物中，SPL通过与B型拟南芥反应调节因子结合来减弱细胞分裂素反应，从而降低芽再生能力，B型拟南芥反应调节因子在细胞分裂素信号通路中编码转录激活因子。一致地，增加外源细胞分裂素的量可以补充老植物中降低的芽再生能力。因此，响应细胞分裂素而招募的年龄线索有助于芽再生能力。
