盐碱胁迫是限制农业生产和作物产量的主要逆境因素之一。近年来, 植物响应盐胁迫的分子机制研究取得了较大进展, 但是对碱胁迫的分子机制知之甚少, 这制约了通过分子设计育种提高作物盐碱胁迫耐受性的研究进程。最近, 中国科学院遗传与发育生物学研究所谢旗团队、中国农业大学于菲菲团队和华中农业大学欧阳亦聃团队等8家单位联合攻关, 在解析植物耐碱分子机制方面取得突破性进展。他们通过高粱(Sorghum bicolor)基因组关联分析检测到1个负调控耐碱性的主效基因AT1 (Alkaline tolerance 1)。AT1及其同源基因的敲除增强了高粱、水稻(Oryza sativa)、谷子(Setaria italica)和玉米(Zea mays)耐碱性, 并提高了碱胁迫下的产量。AT1编码非典型G蛋白γ亚基, 它通过调控水通道蛋白PIP2;1的磷酸化水平改变细胞内外H₂O₂的分布, 响应碱胁迫引发的氧化应激。该研究揭示了作物适应碱胁迫的新机制, 对作物抗碱性育种具有重要意义。

Saline-alkali stress is one of the main adverse environmental factors limiting agricultural production and crop yield. In recent years, great progress has been made in the dissection of the molecular mechanisms of plant’s responses to salt stress, but little is known concerning those for alkaline stress. Lack of the knowledge on alkaline tolerance has severely impeded the effort to improve saline and alkaline stress tolerance of crops through molecular designing and breeding. Recently, Professor Qi Xie at the Institute of Genetics and Developmental Biology of Chinese Academy of Sciences, teamed with Dr. Feifei Yu at China Agricultural University and Dr. Yidan Ouyang at Huazhong Agricultural University, made a breakthrough discovery towards the understanding of the molecular regulation of alkaline tolerance. They detected a major gene AT1, which negatively regulates alkaline tolerance, through sorghum genome-wide association study. The knockout of AT1 and its homologous genes increased the tolerance of sorghum, rice, millet and maize to alkali and increased the yield. AT1 encodes an atypical G protein γ subunit, which alters the cellular distribution of H₂O₂ via regulating the phosphorylation level of the aquaporins PIP2;1 to alleviate the alkali-induced oxidative stress in cells. This work reveals a new mechanism in the adaptation of crops to alkaline stress, which is of great significance to crop breeding for alkaline resistance.