Dong Danhui, Deng Qilin, Zhang Jialong, Jia Congyang, Gao Ming, Wang Yiran, Zhang Lei, Zhang Na, Guo Yang-Dong
College of Horticulture, China Agricultural University, Beijing 100193, China.
Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Plant Physiol. 2024 Dec 2;196(4):2654-2668. doi: 10.1093/plphys/kiae519.
Aluminum (Al) stress, a prevalent constraint in acidic soils, inhibits plant growth by inhibiting root elongation through restricted cell expansion. The molecular mechanisms of Al-induced root inhibition, however, are not fully understood. This study aimed to elucidate the role of Small Auxin-up RNAs (SlSAURs), which function downstream of the key Al stress-responsive transcription factor SENSITIVE TO PROTON RHIZOTOXICITY 1 (SlSTOP1) and its enhancer STOP1-INTERACTING ZINC-FINGER PROTEIN 1 (SlSZP1), in modulating root elongation under Al stress in tomato (Solanum lycopersicum). Our findings demonstrated that tomato lines with knocked-out SlSAURs exhibited shorter root lengths when subjected to Al stress. Further investigation into the underlying mechanisms revealed that SlSAURs interact with Type 2C Protein Phosphatases (SlPP2Cs), specifically D-clade Type 2C Protein Phosphatases (SlPP2C.Ds). This interaction was pivotal as it suppresses the phosphatase activity, leading to the degradation of SlPP2C.D's inhibitory effect on plasma membrane H+-ATPase. Consequently, this promoted cell expansion and root elongation under Al stress. These findings increase our understanding of the molecular mechanisms by which Al ions modulate root elongation. The discovery of the SlSAUR-SlPP2C.D interaction and its impact on H+-ATPase activity also provides a perspective on the adaptive strategies employed by plants to cope with Al toxicity, which may lead to the development of tomato cultivars with enhanced Al stress tolerance, thereby improving crop productivity in acidic soils.
铝（Al）胁迫是酸性土壤中普遍存在的一种限制因素，它通过限制细胞扩张来抑制根伸长，从而抑制植物生长。然而，铝诱导根抑制的分子机制尚未完全了解。本研究旨在阐明小生长素上调RNA（SlSAURs）的作用，其在关键的铝胁迫响应转录因子质子根毒性敏感1（SlSTOP1）及其增强子STOP1相互作用锌指蛋白1（SlSZP1）的下游发挥作用，调节番茄（Solanum lycopersicum）在铝胁迫下的根伸长。我们的研究结果表明，敲除SlSAURs的番茄品系在遭受铝胁迫时根长较短。对潜在机制的进一步研究表明，SlSAURs与2C型蛋白磷酸酶（SlPP2Cs）相互作用，特别是D类2C型蛋白磷酸酶（SlPP2C.Ds）。这种相互作用至关重要，因为它抑制了磷酸酶活性，导致SlPP2C.D对质膜H + -ATP酶的抑制作用降解。因此，这促进了铝胁迫下的细胞扩张和根伸长。这些发现增加了我们对铝离子调节根伸长的分子机制的理解。SlSAUR-SlPP2C.D相互作用及其对H + -ATP酶活性的影响的发现，也为植物应对铝毒性所采用的适应性策略提供了一个视角，这可能会导致培育出具有增强铝胁迫耐受性的番茄品种，从而提高酸性土壤中的作物生产力。
