New Phytol.|广州大学生科院李美娜，中科院东北地理农业生态所刘宝辉共同通讯揭示两对同源LHY通过抑制ABA反应负调控大
生物钟在开花、植物激素生物合成和非生物胁迫反应等多种植物生物学过程中起着重要作用。在模式植物中，生物钟基因调节干旱胁迫反应的方式已经得到了很好的证实，而在作物物种中，例如全球主要作物大豆，人们对此知之甚少。本文报道了拟南芥中CCA1/LHY的同源基因--核心时钟成分GmLHYs对大豆抗旱性的负调控作用。4个GmLHY均受干旱诱导表达，其中4个GmLHY突变体的抗旱性显著提高。
转录组分析表明，脱落酸(ABA)信号通路受GmLHY调节以响应抗旱性。遗传分析表明，LHY1a和LHY1b两对同源基因冗余控制干旱反应。
拟南芥和大豆中LHY1a和LHY1b的功能特征进一步支持了GmLHYs在干旱胁迫下通过ABA信号途径维持细胞内环境平衡的观点。
本研究加深了我们对大豆耐旱性潜在分子机制的理解。此外，LHY1a和LHY1b的两个同源物为基因组编辑提供了替代靶点，以快速产生大豆优良品种的突变等位基因，以增强其抗旱性。
The circadian clock plays essential roles in diverse plant biological processes, such as flowering, phytohormone biosynthesis, and abiotic stress responses. The manner in which circadian clock genes regulate drought stress responses in model plants has been well‐established, while comparatively little is known in crop species, such as soybean, a major global crop. This paper reports that the core clock components GmLHYs, the orthologues of CCA1/LHY in Arabidopsis, negatively control drought tolerance in soybean.
The expressions of four GmLHYs were all induced by drought, and the quadruple mutants of GmLHYs demonstrated significantly improved drought tolerance. Transcriptome profiling suggested that the abscisic acid (ABA) signaling pathway is regulated by GmLHYs to respond drought tolerance.
Genetic dissections showed that two homologous pairs of LHY1a and LHY1b redundantly control the drought response. Functional characterization of LHY1a and LHY1b in Arabidopsis and soybean further supported the notion that GmLHYs can maintain cellular homeostasis through the ABA signaling pathway under drought stress.
This study improves our understanding of the underlying molecular mechanisms on soybean drought tolerance. Furthermore, the two homologues of LHY1a and LHY1b provide alternative targets for genome editing to rapidly generate mutant alleles in elite soybean cultivars to enhance their drought tolerance.
Wang, K., Bu, T., Cheng, Q., Dong, L., Su, T., Chen, Z., Kong, F., Gong, Z., Liu, B. and Li, M. (2020), Two homologous LHY pairs negatively control soybean drought tolerance by repressing the ABA responses. New Phytol. Accepted Author Manuscript. doi:10.1111/nph.17019
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