Danzer John, Mellott Eric, Bui Anhthu Q, Le Brandon H, Martin Patrick, Hashimoto Meryl, Perez-Lesher Jeanett, Chen Min, Pelletier Julie M, Somers David A, Goldberg Robert B, Harada John J
Monsanto Company, Agracetus Campus, Middleton, Wisconsin 53562 (J.D., E.M., P.M., J.P.-L., D.A.S);Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (A.Q.B., B.H.L., M.C., R.B.G.); andDepartment of Plant Biology, University of California, Davis, California 95616 (M.H., J.M.P., J.J.H.).
Monsanto Company, Agracetus Campus, Middleton, Wisconsin 53562 (J.D., E.M., P.M., J.P.-L., D.A.S);Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095 (A.Q.B., B.H.L., M.C., R.B.G.); andDepartment of Plant Biology, University of California, Davis, California 95616 (M.H., J.M.P., J.J.H.)
Plant Physiol. 2015 Jul;168(3):1025-35. doi: 10.1104/pp.15.00432. Epub 2015 May 11.
We used an RNA interference screen to assay the function of 53 transcription factor messenger RNAs (mRNAs) that accumulate specifically within soybean (Glycine max) seed regions, subregions, and tissues during development. We show that basic helix-loop-helix (bHLH) transcription factor genes represented by Glyma04g41710 and its paralogs are required for the formation of stoma in leaves and stomatal precursor complexes in mature embryo cotyledons. Phylogenetic analysis indicates that these bHLH transcription factor genes are orthologous to Arabidopsis (Arabidopsis thaliana) SPEECHLESS (SPCH) that initiate asymmetric cell divisions in the leaf protoderm layer and establish stomatal cell lineages. Soybean SPCH (GmSPCH) mRNAs accumulate primarily in embryo, seedling, and leaf epidermal layers. Expression of Glyma04g41710 under the control of the SPCH promoter rescues the Arabidopsis spch mutant, indicating that Glyma04g41710 is a functional ortholog of SPCH. Developing soybean embryos do not form mature stoma, and stomatal differentiation is arrested at the guard mother cell stage. We analyzed the accumulation of GmSPCH mRNAs during soybean seed development and mRNAs orthologous to MUTE, FAMA, and inducer of C-repeat/dehydration responsive element-binding factor expression1/scream2 that are required for stoma formation in Arabidopsis. The mRNA accumulation patterns provide a potential explanation for guard mother cell dormancy in soybean embryos. Our results suggest that variation in the timing of bHLH transcription factor gene expression can explain the diversity of stomatal forms observed during plant development.
我们利用RNA干扰筛选来分析53种转录因子信使核糖核酸（mRNA）的功能，这些转录因子mRNA在大豆（Glycine max）种子发育过程中的特定区域、亚区域和组织中特异性积累。我们发现，以Glyma04g41710及其旁系同源基因代表的碱性螺旋-环-螺旋（bHLH）转录因子基因是叶片气孔形成以及成熟胚子叶气孔前体复合物形成所必需的。系统发育分析表明，这些bHLH转录因子基因与拟南芥（Arabidopsis thaliana）中在叶原表皮层启动不对称细胞分裂并建立气孔细胞谱系的无口（SPEECHLESS，SPCH）基因直系同源。大豆SPCH（GmSPCH）mRNA主要在胚、幼苗和叶片表皮层积累。在SPCH启动子控制下的Glyma04g41710表达可拯救拟南芥spch突变体，这表明Glyma04g41710是SPCH的功能直系同源基因。发育中的大豆胚不形成成熟气孔，气孔分化在保卫母细胞阶段停滞。我们分析了大豆种子发育过程中GmSPCH mRNA的积累情况，以及与拟南芥气孔形成所需的MUTE、FAMA和C-重复/脱水响应元件结合因子表达诱导因子1/尖叫2直系同源的mRNA。mRNA积累模式为大豆胚中保卫母细胞休眠提供了一种潜在解释。我们的结果表明，bHLH转录因子基因表达时间的变化可以解释植物发育过程中观察到的气孔形态多样性。
