Zhang Binglei, Wang Yihua, Zhu Yun, Pan Tian, Yan Haigang, Wang Xin, Jing Ruonan, Wu Hongming, Wang Fan, Zhang Yu, Bao Xiuhao, Wang Yongfei, Zhang Pengcheng, Chen Yu, Duan Erchao, Han Xiaohang, Wan Gexing, Yan Mengyuan, Sun Xiejun, Lei Cailin, Cheng Zhijun, Zhao Zhichao, Jiang Ling, Bao Yiqun, Ren Yulong, Wan Jianmin
State Key Laboratory of Crop Gene Resources and Breeding, National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
J Integr Plant Biol. 2025 Jan;67(1):35-54. doi: 10.1111/jipb.13792. Epub 2024 Oct 30.
Autophagy is a highly conserved cellular program in eukaryotic cells which mediates the degradation of cytoplasmic components through the lysosome, also named the vacuole in plants. However, the molecular mechanisms underlying the fusion of autophagosomes with the vacuole remain unclear. Here, we report the functional characterization of a rice (Oryza sativa) mutant with defects in storage protein transport in endosperm cells and accumulation of numerous autophagosomes in root cells. Cytological and immunocytochemical experiments showed that this mutant exhibits a defect in the fusion between autophagosomes and vacuoles. The mutant harbors a loss-of-function mutation in the rice homolog of Arabidopsis thaliana MONENSIN SENSITIVITY1 (MON1). Biochemical and genetic evidence revealed a synergistic interaction between rice MON1 and AUTOPHAGY-RELATED 8a in maintaining normal growth and development. In addition, the rice mon1 mutant disrupted storage protein sorting to protein storage vacuoles. Furthermore, quantitative proteomics verified that the loss of MON1 function influenced diverse biological pathways including autophagy and vacuolar transport, thus decreasing the transport of autophagic and vacuolar cargoes to vacuoles. Together, our findings establish a molecular link between autophagy and vacuolar protein transport, and offer insights into the dual functions of the MON1-CCZ1 (CAFFEINE ZINC SENSITIVITY1) complex in plants.
自噬是真核细胞中一种高度保守的细胞程序，它通过溶酶体介导细胞质成分的降解，在植物中溶酶体也被称为液泡。然而，自噬体与液泡融合的分子机制仍不清楚。在这里，我们报道了一个水稻（Oryza sativa）突变体的功能特征，该突变体在胚乳细胞中储存蛋白运输存在缺陷，且在根细胞中积累了大量自噬体。细胞学和免疫细胞化学实验表明，该突变体在自噬体与液泡的融合方面存在缺陷。该突变体在拟南芥MONENSIN SENSITIVITY1（MON1）的水稻同源物中存在功能丧失突变。生化和遗传学证据揭示了水稻MON1与自噬相关蛋白8a在维持正常生长发育过程中的协同相互作用。此外，水稻mon1突变体破坏了储存蛋白向蛋白储存液泡的分选。此外，定量蛋白质组学证实，MON1功能的丧失影响了包括自噬和液泡运输在内的多种生物学途径，从而减少了自噬和液泡货物向液泡的运输。总之，我们的研究结果建立了自噬与液泡蛋白运输之间的分子联系，并为植物中MON1-CCZ1（咖啡因锌敏感性1）复合物的双重功能提供了见解。
