Data_Sheet_1_The Sweetpotato BTB-TAZ Protein Gene, IbBT4, Enhances Drought Tolerance in Transgenic Arabidopsis.pdf

BTB-TAZ (BT)-domain proteins regulate plant development and pathogen defense. However, their roles in resistance to abiotic stresses remain largely unknown. In this study, we found that the sweetpotato BT protein-encoding gene IbBT4 significantly enhanced the drought tolerance of Arabidopsis. IbBT4 expression was induced by PEG6000, H2O2 and brassinosteroids (BRs). The IbBT4-overexpressing Arabidopsis seeds presented higher germination rates and longer roots in comparison with those of WT under 200 mM mannitol stress. Under drought stress the transgenic Arabidopsis plants exhibited significantly increased survival rates and BR and proline contents and decreased water loss rates, MDA content and reactive oxygen species (ROS) levels. IbBT4 overexpression upregulated the BR signaling pathway and proline biosynthesis genes and activated the ROS-scavenging system under drought stress. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays revealed that the IbBT4 protein interacts with BR-ENHANCED EXPRESSION 2 (BEE2). Taken together, these results indicate that the IbBT4 gene provides drought tolerance by enhancing both the BR signaling pathway and proline biosynthesis and further activating the ROS-scavenging system in transgenic Arabidopsis.

BTB-TAZ（BT）领域蛋白调控植物发育及病原体防御。然而，其在抗非生物胁迫中的作用尚不明确。本研究发现，甘薯BT蛋白编码基因IbBT4显著提高了拟南芥的抗旱性。IbBT4的表达受PEG6000、H2O2和 brassinosteroids（BRs）诱导。与野生型（WT）相比，IbBT4过表达拟南芥种子在200 mM甘露醇胁迫下表现出更高的发芽率和更长的根系。在干旱胁迫下，转基因拟南芥植株显示出显著提高的存活率、BR和脯氨酸含量，以及降低的水分损失率、丙二醛（MDA）含量和活性氧（ROS）水平。IbBT4过表达上调了BR信号通路和脯氨酸生物合成基因，并在干旱胁迫下激活了ROS清除系统。酵母双杂交（Y2H）和双分子荧光互补（BiFC）实验揭示了IbBT4蛋白与BR-ENHANCED EXPRESSION 2（BEE2）的相互作用。综合上述结果，表明IbBT4基因通过增强BR信号通路和脯氨酸生物合成，并在转基因拟南芥中进一步激活ROS清除系统，从而提供抗旱性。