曲古抑菌素A对沙棘扦插苗响应干旱和复水及相关基因表达的影响

Effects of Trichostatin A on Responses of Sea Buckthorn toDrought and Rehydration and Related Gene Expression

[目的]研究组蛋白去乙酰化酶抑制剂曲古抑菌素A(Trichostatin A,TSA)在20%聚乙二醇模拟干旱和干旱后复水条件下,对沙棘扦插苗叶片形态、光合指标、脯氨酸、丙二醛和脱落酸含量等生理特性和组蛋白去乙酰化酶、合成脱落酸和类黄酮相关基因表达的影响。[方法]测定沙棘扦插苗干旱相关生理指标,实时定量PCR检测基因表达量。[结果]1μmol·L^(−1)TSA预处理的沙棘在同等干旱胁迫下耐旱性增强。与仅干旱处理相比,(1)叶片下垂和萎蔫程度降低,植株鲜质量下降程度更小,复水后植株恢复程度更大。(2)净光合速率、蒸腾速率、气孔导度、PSII最大光化学效率Fv/Fm值、PSII有效光化学量子产量Y(Ⅱ)值和叶绿素相对含量(SPAD)值均显著上调,复水后均下调。(3)脯氨酸和类黄酮含量显著上调,丙二醛和脱落酸含量显著下调,复水后趋势相同。(4)组蛋白去乙酰化酶基因HrHDA6和HrHDA19、脱落酸合成相关基因ABF1和NAC2表达均显著下调,类黄酮合成相关基因C4H2和CHS4表达均显著上调,复水后趋势相同。[结论]TSA通过调控沙棘扦插苗生理和基因表达参与对干旱胁迫的响应,可以提高沙棘的抗旱性,该研究为深入解析组蛋白乙酰化影响沙棘抗旱的调控机制奠定重要基础。

[Objective]To study the effects of the histone deacetylase inhibitor Trichostatin A(TSA)on the physiological characteristics of leaf morphology,photosynthetic indexes,proline,malondialdehyde and abscisic acid content,synthetic histone deacetylase,abscisic acid and flavonoid-related genes of sea buckthorn cuttings under the conditions of simulated drought and post-drought rehydration of 20%polyethylene glycol.[Methods]The drought-related physiological indexes of sea buckthorn cuttings were measured,and the gene expression was detected by quantitative real-time PCR.[Result]TSA-pretreated(1μmol·L^(−1))sea buckthorn was enhanced in drought tolerance under equal drought stress.Compared with the drought treatment,(1)the degree of leaf sagging and wilting reduced,the degree of fresh weight decline was smaller,and the degree of plant recovery after rehydration was greater.(2)The net photosynthetic rate,transpiration rate,stomatal conductivity,PSII maximum photochemical efficiency Fv/Fm value,PSII effective photochemical quantum yield Y(II)value and chlorophyll relative content(SPAD)value all significantly increased,and all were adjusted down after rehydration.(3)The content of proline and flavonoids increased significantly,the content of malondialdehyde and abscisic acid decreased significantly,and the trend was the same after rehydration.(4)The expression of histone deacetylase genes HrHDA6 and HrHDA19,abscisic acid synthesis-related genes ABF1 and NAC2 were significantly down-regulated,and the expression of flavonoid synthesis-related genes C4H2 and CHS4 were significantly upregulated,and the trend after rehydration was the same.[Conclusion]TSA can improve the drought resistance of sea buckthorn by regulating the physiological and gene expression of sea buckthorn cuttings in response to drought stress,and this study lays an important foundation for in-depth analysis of the regulatory mechanism of histone acetylation affecting sea buckthorn drought resistance.