| 胡杨miR1444b在拟南芥中正调控植物抗旱性 |
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| 引用本文： | 李双,苏艳艳,王厚领,李惠广,刘超,夏新莉,尹伟伦.胡杨miR1444b在拟南芥中正调控植物抗旱性[J].北京林业大学学报,2018,40(4):1-9. |
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| 作者姓名： | 李双 苏艳艳 王厚领 李惠广 刘超 夏新莉 尹伟伦 |
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| 作者单位： | 北京林业大学生物科学与技术学院，林木育种国家工程实验室，北京 100083 |
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| 基金项目： | 转基因生物新品种培育重大专项(2018ZX08021001)，国家自然科学基金项目(31570308、31600484、31770649) |
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| 摘 要： | 目的miR1444b是木本植物特异miR1444家族中的一员，能够参与植物对金属胁迫的响应，但在干旱胁迫响应中的功能尚不明确。方法本实验克隆得到了胡杨MIR1444b基因(peu-MIR1444b)及其启动子(pro-peu-MIR1444b)，将peu-MIR1444b基因在模式植株拟南芥中过表达，对转基因植株进行正常浇水、甘露醇模拟干旱和自然干旱条件处理，研究peu-MIR1444b的功能。结果克隆得到的pro-peu-MIR1444b和peu-MIR1444b与Phytozome数据库收录的毛果杨基因组序列相似性分别为99.61%和98.82%。利用PlantCARE数据库分析发现，pro-peu-MIR1444b序列中包含逆境相关的TC-rich repeats元件和受干旱诱导的MYB结合位点MBS。实时荧光定量PCR分析显示miR1444b在转基因拟南芥中表达量显著高于野生型，预测的靶基因葡聚糖合成酶Ⅳ(AT3G14570.2)表达量明显下调，初步确定葡聚糖合成酶Ⅳ在拟南芥中被peu-miR1444b负调控。在250 mmol/L甘露醇模拟的干旱胁迫条件下，转基因拟南芥株系TG-2和TG-5萌发率分别显著高于野生型20.83%和26.67%，根长分别显著高于野生型56.83%和52.60%(P < 0.05)。土壤自然干旱8 d测得转基因拟南芥的光合速率、气孔导度、叶片水分利用效率、PSⅡ最大光化学效率和过氧化物酶(POD)活性均显著高于野生型(P < 0.05)。结论胡杨miR1444b可以促进根系生长增加植物的吸水能力，负调控葡聚糖合成酶Ⅳ提高植物的渗透调节能力，维持植物在水分亏缺条件下的光合效率，保证植株正常生长，在拟南芥中正调控植物抗旱性。
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| 关 键 词： | 胡杨 miR1444b 干旱 甘露醇 光合速率 |
| 收稿时间： | 2018-01-30 |
Populus euphratica miR1444b positively regulates plants response to drought stress in Arabidopsis thaliana |
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| Li Shuang,Su Yanyan,Wang Houling,Li Huiguang,Liu Chao,Xia Xinli,Yin Weilun.Populus euphratica miR1444b positively regulates plants response to drought stress in Arabidopsis thaliana[J].Journal of Beijing Forestry University,2018,40(4):1-9. |
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| Authors: | Li Shuang Su Yanyan Wang Houling Li Huiguang Liu Chao Xia Xinli Yin Weilun |
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| Institution: | College of Biological Sciences and Biotechnology, National Engineering Laboratory for Tree Breeding, Beijing Forestry University, Beijing 100083, China |
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| Abstract: | Objective miR1444b is a member of woody plant specific miR1444 family participating in plant response to metal stress. However, its function in response to drought stress is unknown.Method We isolated Populus euphratica MIR1444b gene (peu-MIR1444b) and its promoter (pro-peu-MIR1444b), then overexpressed peu-MIR1444b gene at the model plant Arabidopsis thaliana. The peu-MIR1444b gene's function was analyzed under normal watering, mannitol-simulated drought and natural soil drought conditions.Result We compared the genomic sequence homology of Populus trichocarpa collected from the Phytozome database with the pro-peu-MIR1444b and peu-MIR1444b, which sharing 99.61% and 98.82% similarity, respectively. Analysis using the PlantCARE database revealed that the pro-peu-MIR1444b sequence contained the stress-related TC-rich repeat elements and the drought-induced MYB binding site MBS. QRT-PCR results showed that transgenic lines had significantly higher expression level of miR1444b than in wild type, the expression level of target gene glucan synthase-like Ⅳ (AT3G14570.2) was down-regulated, and it indicated that glucan synthase-like Ⅳ was negatively regulated by peu-miR1444b in A. thaliana. Under 250 mmol/L mannitol-simulated drought stress condition, germination rate of TG-2 and TG-5 in transgenic lines was significantly higher than wild-type by 20.83% and 26.67%, and their root length was drastically higher than wild-type by 56.83% and 52.60%(P < 0.05), respectively. At 8 days after natural soil drought treatment, photosynthetic rate, stomatal conductance, PSⅡ maximum photochemical efficiency, leaf water use efficiency and peroxidase (POD) activity in transgenic lines were obviously higher than those in wild type (P < 0.05).Conclusion Our study reveals that miR1444b increases water absorption capacity of plants by promoting root growth, negative regulation of glucan synthase-like Ⅳ enhance plant osmotic adjustment ability to maintain plant photosynthetic efficiency under water deficit environment, ensure the normal growth of plants. miR1444b positively regulates plant response to drought stress in A. thaliana. |
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