Key Laboratory of Soybean Biology of Ministry of Education China, Northeast Agricultural University, Harbin 150030, China.
Institute of Crop Cultivation and Tillage, Heilongjiang Academy of Agricultural Sciences, Harbin 150028, China.
Plant Physiol. 2023 Apr 3;191(4):2427-2446. doi: 10.1093/plphys/kiac573.
Salt and drought stresses are major factors limiting soybean (Glycine max [L.] Merr.) growth and development; thus, improving soybean stress tolerance is critical. In this study, both salt stress and drought stress induced mRNA levels of CONSTANS-like 1a (GmCOL1a) and stabilized the GmCOL1a protein. Transgenic 35S:GmCOL1a soybean plants exhibited enhanced salt and drought tolerance, with higher relative water content in leaves, greater proline content, lower malondialdehyde (MDA) content, and less reactive oxygen species (ROS) production compared with wild-type plants; the GmCOL1a knockout co-9 mutant showed opposite phenotypes. In addition, GmCOL1a promoted the expression of genes related to salt tolerance, effectively reducing the Na+/K+ ratio in soybean plants, especially in stems and leaves of 35S:GmCOL1a soybean. Chromatin immunoprecipitation sequencing (ChIP-seq) analysis identified two potential direct targets of GmCOL1a, late embryogenesis abundant (GmLEA) and Δ1-pyrroline-5-carboxylate synthetase (GmP5CS) genes, which were verified by chromatin immunoprecipitation quantitative polymerase chain reaction (ChIP-qPCR), electrophoretic mobility shift assay (EMSA), and transient transcriptional activation assays. GmCOL1a bound directly to the Myc(bHLH)-binding and Che-binding motifs of GmLEA and GmP5CS promoters to stimulate mRNA expression. Analysis of transgenic hairy-root GmP5CS:GmP5CS soybean plants in wild type, co-9, and 35S:GmCOL1a backgrounds further revealed that GmCOL1a enhances salt and drought tolerance by promoting GmP5CS protein accumulation in transgenic soybean hairy roots. Therefore, we demonstrate that GmCOL1a plays an important role in tolerance to abiotic stress in soybean.
盐胁迫和干旱胁迫诱导大豆（Glycine max [L.] Merr.）CONSTANS-like 1a（GmCOL1a）的 mRNA 水平升高，并稳定 GmCOL1a 蛋白。转 GmCOL1a 基因 35S:GmCOL1a 大豆植株表现出增强的耐盐性和耐旱性，叶片相对含水量较高，脯氨酸含量较高，丙二醛（MDA）含量较低，活性氧（ROS）生成较少，与野生型植株相比；GmCOL1a 敲除 co-9 突变体表现出相反的表型。此外，GmCOL1a 促进与耐盐性相关基因的表达，有效降低大豆植株的 Na+/K+比值，尤其是在 35S:GmCOL1a 大豆的茎和叶中。染色质免疫沉淀测序（ChIP-seq）分析鉴定了 GmCOL1a 的两个潜在直接靶标，即 late embryogenesis abundant（GmLEA）和 Δ1-pyrroline-5-carboxylate synthetase（GmP5CS）基因，通过染色质免疫沉淀定量聚合酶链反应（ChIP-qPCR）、电泳迁移率变动分析（EMSA）和瞬时转录激活实验得到验证。GmCOL1a 直接结合到 GmLEA 和 GmP5CS 启动子的 Myc(bHLH)-结合和 Che 结合基序上，刺激 mRNA 表达。在野生型、co-9 和 35S:GmCOL1a 背景下分析转 GmP5CS:GmP5CS 大豆毛状根的转基因植株进一步表明，GmCOL1a 通过促进转基因大豆毛状根中 GmP5CS 蛋白的积累来增强耐盐性和耐旱性。因此，我们证明 GmCOL1a 在大豆非生物胁迫耐受中起重要作用。
