Key Laboratory of Soybean Biology of Chinese Education Ministry (Key Laboratory of Biology and Genetics & Breeding for Soybean in Northeast China), Northeast Agricultural University, Harbin 150030, China.
Plant Mol Biol. 2013 Jun;82(3):279-99. doi: 10.1007/s11103-013-0062-z. Epub 2013 May 1.
Soybean is a typical short-day crop, and its photoperiodic and gibberellin (GA) responses for the control of flowering are critical to seed yield. The GmGBP1 mRNA abundance in leaves was dramatically increased in short-days (SDs) compared to that in long-days in which it was consistently low at all time points from 0 to 6 days (days after transfer to SDs). GmGBP1 was highly expressed in leaves and exhibited a circadian rhythm in SDs. Ectopic overexpression of GmGBP1 in tobaccos caused photoperiod-insensitive early flowering by increasing NtCO mRNA levels. GmGBP1 mRNA abundance was also increased by GAs. Transgenic GmGBP1 overexpressing (-ox) tobacco plants exhibited increased GA signaling-related phenotypes including flowering and plant height promotion. Furthermore, the hypocotyl elongation, early-flowering and longer internode phenotypes were largely accelerated by GA3 application in the GmGBP1-ox tobacco seedlings. Being consistent, overexpression of GmGBP1 resulted in significantly enhanced GA signaling (evidenced suppressed expression of NtGA20ox) both with and without GA treatments. GmGBP1 was a positive regulator of both photoperiod and GA-mediated flowering responses. In addition, GmGBP1-ox tobaccos were hypersensitive to ABA, salt and osmotic stresses during seed germination. Heat-inducible GmGBP1 also enhanced thermotolerance in transgenic GmGBP1-ox tobaccos during seed germination and growth. GmGBP1 protein was localized in the nucleus. Analyses of a series of 5'-deletions of the GmGBP1 promoter suggested that several cis-acting elements, including P-BOX, TCA-motif and three HSE elements necessary to induce gene expression by GA, salicic acid and heat stress, were specifically localized in the GmGBP1 promoter region.
大豆是一种典型的短日照作物，其光周期和赤霉素（GA）反应对开花的控制对种子产量至关重要。与长日照相比，在短日照条件下（SDs）叶片中的 GmGBP1 mRNA 丰度显著增加，而在长日照条件下，从 0 到 6 天（转移到 SD 后的天数）的所有时间点，GmGBP1 的mRNA 丰度一直很低。GmGBP1 在叶片中高度表达，并在 SD 中表现出昼夜节律。在烟草中异位过表达 GmGBP1 通过增加 NtCO mRNA 水平导致光周期不敏感的早期开花。GA 也能增加 GmGBP1 的 mRNA 丰度。转 GmGBP1 过表达（-ox）烟草植株表现出增加的 GA 信号相关表型，包括开花和株高促进。此外，在 GmGBP1-ox 烟草幼苗中，GA3 的应用极大地加速了下胚轴伸长、早期开花和节间伸长的表型。一致的是，无论是否有 GA 处理，过表达 GmGBP1 都会导致 GA 信号显著增强（表现为 NtGA20ox 的表达受到抑制）。GmGBP1 是光周期和 GA 介导的开花反应的正调节剂。此外，GmGBP1-ox 烟草在种子萌发过程中对 ABA、盐和渗透胁迫敏感。热诱导的 GmGBP1 也增强了转基因 GmGBP1-ox 烟草在种子萌发和生长过程中的耐热性。GmGBP1 蛋白定位于细胞核内。对 GmGBP1 启动子的一系列 5'缺失分析表明，几个顺式作用元件，包括 P-BOX、TCA 基序和三个 HSE 元件，是通过 GA、水杨酸和热胁迫诱导基因表达所必需的，它们在 GmGBP1 启动子区域中被特异性定位。
