| 摘要: |
| 【目的】研究干旱胁迫下MYB转录因子家族基因SlMYB43对番茄幼苗光合特性的调控作用，为后续 完善油菜素内酯受体基因SlBRI1参与调控植物抗旱性的机制提供参考，同时为今后深入研究MYB转录因子家族与 植物抗旱性之间的关系提供理论依据。【方法】以番茄品种‘Micro Tom’野生型植株（WT）及SlMYB43过表达株系（SlMYB43-6、SlMYB43-19）为试验材料，测定干旱胁迫36 h内番茄离体叶片失水率，干旱胁迫0和5 d叶片光合气体交换参数净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾速率（Tr），叶片叶绿素荧光参数最大光化学效率（Fv/Fm）、实际光能转化效率（ΦPSⅡ）、最大光能转化效率（Fv'/Fm'）、光化学淬灭系数（qP），以及逆境响应基因（SlFeSOD、SlDREB、SlCAT1、SlLeP5CS）的表达水平。【结果】所有番茄植株离体叶片失水率均随时间延长而逐渐增大， 且相同时间段里过表达株系离体叶片失水率均显著高于野生型；干旱胁迫5 d后所有番茄植株叶片均出现萎焉现象，但过表达植株叶片萎焉更严重。同时，所有植株叶片Pn、Gs、Tr以及各叶绿素荧光参数在干旱胁迫下均大幅下降，Ci则大幅上升，并且过表达植株的Pn和各叶绿素荧光参数均显著低于WT植株，而其Gs、Tr和Ci显著高于WT植株。所有番茄植株干旱胁迫响应基因表达水平均较胁迫前大幅提高，过表达植株SlDREB的表达水平在干旱胁迫后显著高于WT植株，其余干旱胁迫响应基因表达水平则显著低于WT植株。【结论】过表达SlMYB43将降低番茄植株干旱胁迫响应基因的表达水平，加重干旱胁迫对光合作用的抑制程度，显著降低番茄植株的抗旱能力。 |
| 关键词: 番茄 干旱胁迫 过表达SlMYB43 光合参数 逆境响应基因 |
| DOI：10. 13207/j. jnwafu. 2026. 12. 011 |
| 分类号: |
| 基金项目:四川省科技厅面上基金项目（2024NSFSC0396） |
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| Effects of overexpression of SlMYB43 on the photosynthetic characteristics of tomato plants under drought stress |
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LI Jjiajia, TAN Qianwen, XIE Can, TU Linna, NIE Shuming, WANG Dan
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Key Laboratory of Southwest China Wildlife Resources Conservation，College of Life Science，China West Normal University， Nanchong，Sichuan 637000，China
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| Abstract: |
| 【Objective】This study investigates the regulatory role of the MYB transcription factor family genes in the photosynthetic characteristics of tomato seedlings under drought stress，to provide information for further research on the relationship between the MYB transcription factor family and plant drought resistance. 【Method】Wild-type（WT） plants and SlMYB43-overexpressing lines（SlMYB43-6，SlMYB43-19） of to-mato cultivar‘ Micro Tom’ were used as experimental materials. The water loss rate of the detached tomato leaves within 36 hours of drought stress was measured. And the leaf photosynthetic gas exchange parameters，including net photosynthetic rate（Pn），stomatal conductance（Gs），intercellular CO2 concentration（Ci），and transpi-ration rate（Tr），leaf chlorophyll fluorescence parameters including maximum photochemical efficiency（Fv/Fm），actual photochemical efficiency（ΦPSII），maximum photochemical efficiency in light-adapted state（Fv'/Fm'），and the coefficient of photochemical quenching（qP） were measured. And the expression levels of stress response genes（SlFe‐SOD，SlDREB，SlCAT1，SlLeP5CS） on day 0 and day 5 of drought stress was determined.【Result】The water loss rate of detached leaves from all tomato plants gradually increased over time，and the water loss rate of detached leaves from SlMYB43-overexpressing lines was significantly higher than that of the WT plants within the same duration. After 5 days of drought stress，wilting of leaves occurred in all tomato plants，with more severe wilting observed in SlMYB43-overexpressing plants. Meanwhile，under drought stress，all to-mato plant leaves showed a significant decrease in Pn，Gs，Tr，and various chlorophyll fluorescence parameters，but a significant increase in Ci.Additionally，SlMYB43-overexpressing plants had significantly lower Pn and chlorophyll fluorescence parameters than WT plants，while their Gs，Tr，and Ci were significantly higher than those of WT plants. The expression levels of all drought-responsive genes in these plants increased significantly compared to normal conditions. The SlDREB expression level in SlMYB43-overexpressing plants was significantly higher than that in WT plants after drought stress，while the expression levels of other responsive genes were significantly lower than those in WT plants.【Conclusion】Overexpression of SlMYB43 can reduce the expression levels of drought stress-response genes in tomato plants，aggravate the inhibition of photosynthesis by drought stress，and significantly reduce the drought resistance of tomato plants. |
| Key words: Solanum lycopersicum L. drought stress overexpression of SlMYB43 photosynthetic param-eters stress response genes |
