| 摘要: |
| 【目的】以前期从四季秋海棠叶片中克隆得到的R2R3型MYB转录因子BsMYB62为研究对象，分析其在干旱胁迫下的功能。【方法】对四季秋海棠MYB62蛋白进行亚细胞定位，并通过实时荧光定量PCR方法明确BsMYB62基因在四季秋海棠根、茎、叶、雄花和雌花5个组织部位中的表达情况；构建BsMYB62基因的过表达载体转化到拟南芥，观察过表达转基因株系与野生型植株在萌发期和幼苗期遭受干旱胁迫时的生长表型、种子萌发和根长情况，测定各株系在幼苗期干旱胁迫处理时的叶绿素荧光参数PSⅡ最大光化学效率（Fv/Fm），叶绿素、丙二醛（MDA）、脯氨酸（Pro）含量，抗氧化酶（SOD、POD、CAT）活性以及转基因株系中BsMYB62基因的相对表达量变化。【结果】BsMYB62定位于四季秋海棠的细胞核，其在根、茎、叶和雌雄花中均有表达，其中以根和茎中的表达水平较高。在MS培养基中，野生型拟南芥和3个BsMYB62过表达转基因株系（OE1、OE2和OE3）的发芽率和长势均无显著差异，而在200 mmol/L甘露醇（模拟干旱胁迫）培养基中，OE1、OE2和OE3在胁迫处理后前2 d的发芽率及主根长均显著高于野生型拟南芥，幼苗长势也明显优于野生型。置于培养土中干旱胁迫1 d时，OE1、OE2和OE3的BsMYB62即被显著诱导；干旱胁迫13 d时，OE1、OE2和OE3的Fv/Fm、叶绿素含量、Pro含量以及SOD、POD和CAT活性均显著高于野生型拟南芥，而MDA含量则显著低于野生型拟南芥。【结论】BsMYB62基因通过提高转基因拟南芥的光合潜能和抗氧化能力，显著增强其对干旱胁迫的抗性。 |
| 关键词: 四季秋海棠 BsMYB62转录因子 亚细胞定位 组织特异性表达 干旱胁迫 |
| DOI： |
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| 基金项目:国家自然科学基金面上项目（32172622） |
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| Drought tolerance functions of BsMYB62 in Begonia semperflorens |
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LIU Baoguo,ZHANG Yanwen,YAO Kexin,et al
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| Abstract: |
| 【Objective】This study analyzed the functions of BsMYB62 cloned from leaves of Begonia semperflorens under drought stress.【Method】Subcellular localization analysis of MYB62 protein in B. semperflorens was performed.The expressions of BsMYB62 in roots,stems,leaves,male flowers and female flowers of B. semperflorens were analyzed.The overexpression vector of BsMYB62 gene was transformed into Arabidopsis thaliana to analyze the differences between overexpressed strains and wild type plants under drought stress.The chlorophyll fluorescence parameters PSⅡ maximum photochemical efficiency (Fv/Fm),contents of chlorophyll,malondialdehyde (MDA) and proline (Pro),activities of antioxidant enzymes (SOD,POD and CAT) and relative expression of BsMYB62 gene in transgenic lines were determined.【Result】BsMYB62 was located in the nucleus with higher expressions in roots and stems than in leaves,male and female flowers in B. semperflorens.In MS medium,no significant differences in germination rate and growth were observed between A. thaliana (WT) and three BsMYB62 over-expression lines (OE1,OE2 and OE3).OE1,OE2 and OE3 showed higher germination rate,better growth and longer main root at 2 days after being treated with drought stress than those of WT in 200 mmol/L mannitol (simulated drought stress) medium.The expression of BsMYB62 was significantly induced in OE1,OE2 and OE3 at 1 day after being placed in cultivated soil under drought stress.Compared with WT,all the three OE lines showed lower MDA content,but higher Fv/Fm,contents of chlorophyll and Pro as well as activities of SOD,POD and CAT when being treated with drought stress for 13 days.【Conclusion】BsMYB62 gene significantly enhanced the resistance of transgenic A. thaliana to drought stress by improving photosynthetic potential and antioxidant capacity. |
| Key words: Begonia semperflorens BsMYB62 transcription factor subcellular localization tissue-specific expression drought stress |
