Data_Sheet_1_Overexpression of GmGAMYB Accelerates the Transition to Flowering and Increases Plant Height in Soybean.xlsx

The flowering time and plant height of soybean are important agronomic characters, which control the adaptability and yield of soybean. R2R3 MYB transcription factor plays an important regulatory role in plant growth and development. In this study, soybean GmGAMYB gene of R2R3-MYB type was induced by long-days (LDs). GmGAMYB showed higher transcriptional levels in the flowers, leaves and pods of soybean. Overexpression of GmGAMYB in transgenic soybean showed earlier flowering time and maturity in LDs and short-days (SDs). GmGAMYB interacted with GmGBP1 and might promote flowering time by up-regulating the expression of GmFULc gene in soybean. Moreover, the expression level of GmGAMYB was also induced by gibberellins (GAs) and the plant height of GmGAMYB-ox plants was significantly increased, which was caused by the enlargement of internode cell in stem. Furthermore, GmGAMYB overexpression led to increased GA sensitivity in the hypocotyl of soybean seedlings compared with WT. GmGAMYB may be a positive regulator of GA response of promoting plant height by up-regulating the expression of GmGA20ox gene in soybean. Together, our studies preliminarily showed that the partial functions of GmGAMYB in regulating flowering time and GA pathway.

大豆开花期与株高是重要的农艺性状，二者共同调控大豆的适应性与产量。R2R3-MYB转录因子（R2R3 MYB transcription factor）在植物生长发育过程中发挥重要调控作用。本研究中，R2R3-MYB类大豆GmGAMYB基因可被长日照（LDs）诱导表达。GmGAMYB在大豆花、叶片与豆荚中呈现较高的转录水平。将GmGAMYB在转基因大豆中过表达后，在长日照与短日照（SDs）条件下，转基因植株均表现出开花期与成熟期提前的表型。GmGAMYB可与GmGBP1发生蛋白相互作用，并可能通过上调大豆GmFULc基因的表达来促进开花。此外，GmGAMYB的转录水平还可被赤霉素（GAs）诱导；GmGAMYB过表达株系的株高显著升高，该表型由茎秆节间细胞体积增大所导致。进一步研究发现，与野生型（WT）相比，GmGAMYB过表达会增强大豆幼苗下胚轴对赤霉素的敏感性。GmGAMYB可能通过上调大豆GmGA20ox基因的表达，作为正向调控因子参与赤霉素信号通路以促进株高生长。综上，本研究初步揭示了GmGAMYB在调控开花期与赤霉素信号通路中的部分功能。