School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia.
Plant Mol Biol. 2018 Nov;98(4-5):333-347. doi: 10.1007/s11103-018-0782-1. Epub 2018 Oct 4.
The homologous genes to OsSUT1-5 in wheat were identified and detailed analysed. TaSUT1 was the predominant sucrose transporter group and it illustrated the genotypic variations towards drought during grain filling. Sucrose transporters (SUT) play crucial roles in wheat stem water soluble carbohydrate (WSC) remobilization to grain. To determine the major functional SUT gene groups in shoot parts of wheat during grain development, drought tolerant varieties, Westonia and Kauz, were investigated in field drought experiments. Fourteen homologous genes to OsSUT1-5 were identified on five homeologous groups, namely TaSUT1_4A, TaSUT1_4B, TaSUT1_4D; TaSUT2_5A, TaSUT2_5B, TaSUT2_5D; TaSUT3_1A, TaSUT3_1D; TaSUT4_6A, TaSUT4_6B, TaSUT4_6D; TaSUT5_2A, TaSUT5_2B, and TaSUT5_2D, and their gene structures were analysed. Wheat plants above the ground were harvested from pre-anthesis to grain maturity and the stem, leaf sheath, rachis, lemma and developing grain were used for analysing TaSUT gene expression. Grain weight, thousand grain weight, kernel number per spike, biomass and stem WSC were characterized. The study showed that among the five TaSUT groups, TaSUT1 was the predominant sucrose transporting group in all organs sampled, and the expression was particularly high in the developing grain. In contrast to TaSUT1, the gene expression levels of TaSUT2, TaSUT3 and TaSUT4 were lower, except for TaSUT3 which showed preferential expression in the lemma before anthesis. The TaSUT5 gene group was very weakly expressed in all tissues. The upregulated gene expression of TaSUT1 Westonia type in stem and grain reveal a crucial role in stem WSC remobilization to grain under drought. The high TaSUT1 gene expression and the significant correlations with thousand grain weight (TGW) and kernel number per spike demonstrated the contribution in Kauz's high grain yield in an irrigated environment and high TGW in Westonia under drought stress. Further molecular level identification is required for gene marker development.
在小麦中鉴定到与 OsSUT1-5 同源的基因，并对其进行了详细分析。TaSUT1 是主要的蔗糖转运体组，它在籽粒灌浆期对干旱表现出基因型变化。蔗糖转运体（SUT）在小麦茎部水溶性碳水化合物（WSC）向籽粒再转移中起着至关重要的作用。为了确定小麦籽粒发育过程中茎部的主要功能 SUT 基因群，在田间干旱实验中对耐旱品种 Westonia 和 Kauz 进行了研究。在五个同源群上鉴定到 14 个与 OsSUT1-5 同源的基因，分别是 TaSUT1_4A、TaSUT1_4B、TaSUT1_4D；TaSUT2_5A、TaSUT2_5B、TaSUT2_5D；TaSUT3_1A、TaSUT3_1D；TaSUT4_6A、TaSUT4_6B、TaSUT4_6D；TaSUT5_2A、TaSUT5_2B 和 TaSUT5_2D，并对它们的基因结构进行了分析。在抽穗前到成熟期间，从地上部分收获小麦植株，并对茎、叶鞘、穗轴、外稃和发育中的籽粒进行 TaSUT 基因表达分析。测定了粒重、千粒重、穗粒数、生物量和茎部 WSC。研究表明，在这 5 个 TaSUT 组中，TaSUT1 是所有采样器官中主要的蔗糖转运组，在发育中的籽粒中表达水平特别高。与 TaSUT1 相反，TaSUT2、TaSUT3 和 TaSUT4 的基因表达水平较低，除了 TaSUT3 在抽穗前外稃中表现出优先表达。TaSUT5 基因组在所有组织中表达水平都非常低。在干旱条件下，TaSUT1 Westonia 型在茎和籽粒中的基因表达上调表明其在茎部 WSC 向籽粒再转移中的关键作用。高 TaSUT1 基因表达水平与千粒重（TGW）和穗粒数呈显著正相关，表明 TaSUT1 在 Kauz 高产的灌溉环境和 Westonia 在干旱胁迫下高 TGW 中的作用。还需要进行分子水平鉴定以开发基因标记。
