BRI1-EMS-SUPPRESSOR 1 (BES1) transcription factor is closely associated with the brassinosteroid (BR) signaling pathway and plays an important role in plant growth and development. SLB3 is a member of BES1 transcription factor family and its expression was previously shown to increase significantly in tomato seedlings under drought stress. In the present study, we used virus-induced gene silencing (VIGS) technology to downregulate SLB3 expression to reveal the function of the SLB3 gene under drought stress further. The downregulated expression of SLB3 weakened the drought tolerance of the plants appeared earlier wilting and higher accumulation of H₂O₂ and O₂⁻·, decreased superoxide dismutase (SOD) activity, and increased proline (PRO) and malondialdehyde (MDA) contents and peroxidase (POD) activity. Quantitative real-time PCR (qRT-PCR) analysis of BR-related genes revealed that the expression of SlCPD, SlDWARF and BIN2-related genes was significantly upregulated in SLB3-silenced seedlings under drought stress, but that the expression of TCH4-related genes was downregulated. These results showed that silencing the SLB3 gene reduced the drought resistance of tomato plants and had an impact on the BR signaling transduction which may be probably responsible for the variation in drought resistance of the tomato plants.

BRI1-EMS-SUPPRESSOR 1（BES1）转录因子与油菜素类固醇（BR）信号通路密切相关，并且在植物生长发育中起重要作用。SLB3是BES1转录因子家族的成员，先前已证明其表达在干旱胁迫下的番茄幼苗中显着增加。在本研究中，我们使用病毒诱导的基因沉默（VIGS）技术下调SLB3表达，以进一步揭示SLB3基因在干旱胁迫下的功能。SLB3的下调表达减弱了植物的抗旱性，出现了更早的枯萎和H ₂ O ₂和O _2的较高积累。⁻ ·，降低了超氧化物歧化酶（SOD）活性，并增加了脯氨酸（PRO）和丙二醛（MDA）含量以及过氧化物酶（POD）活性。BR相关基因的实时定量PCR（qRT-PCR）分析表明，干旱胁迫下SLB3沉默的幼苗中SlCPD，SlDWARF和BIN2相关基因的表达明显上调，而TCH4相关基因的表达被下调了。这些结果表明沉默SLB3基因降低了番茄植物的抗旱性，并且对BR信号转导具有影响，这可能是造成番茄植物抗旱性变化的原因。