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林业科学 ›› 2019, Vol. 55 ›› Issue (2): 33-40.doi: 10.11707/j.1001-7488.20190204

• 论文与研究报告 • 上一篇    下一篇

干旱和高盐胁迫下钙离子依赖核酸酶基因CDD对银腺杨84K生长发育的影响

江成, 周厚君, 赵岩秋, 何辉, 楚立威, 宋学勤, 卢孟柱   

  1. 林木遗传育种国家重点实验室 中国林业科学研究院林业研究所 北京 100091
  • 收稿日期:2018-03-05 修回日期:2018-03-22 出版日期:2019-02-25 发布日期:2019-03-20
  • 基金资助:
    国家自然科学基金重点项目"钙调素调控杨树木质部发育的机制研究"(31030018)。

Effects of CDD Gene on the Growth and Development of Populus alba×P. glandulosa ‘84K’ in Response to Drought and Salt Stresses

Jiang Cheng, Zhou Houjun, Zhao Yanqiu, He Hui, Chu Liwei, Song Xueqin, Lu Mengzhu   

  1. State Key Laboratory of Tree Genetics and Breeding Research Institute of Forestry, Chinese Academy of Forestry Beijing 100091
  • Received:2018-03-05 Revised:2018-03-22 Online:2019-02-25 Published:2019-03-20

摘要: [目的]钙离子依赖型脱氧核糖核酸酶(CDD)具有消化单链和双链DNA的活性,但CDD对水分等胁迫的响应尚未明确。本研究以CDD转基因银腺杨84K为材料,分析在干旱和高盐胁迫条件下CDD在84K杨生长中的作用,探讨CDD对干旱和高盐胁迫的响应,可为揭示杨树CDD基因在抗逆中的作用提供参考。[方法]以过表达PtoCDD和敲除PagCDD转基因银腺杨84K组培苗为材料,对其进行模拟干旱和高盐处理,分析其受干旱、高盐非生物胁迫条件下的表型变化,包括植株高、不定根数目。通过切片观察,分析不同处理条件下茎段木质部大小变化。利用qRT-PCR分析在不同处理条件下CDD转基因植株中水通道蛋白基因(PIP)的表达。[结果]与84K对照相比,在正常条件下CDD转基因植株株高没有显著差异,而干旱、高盐条件下CDD缺失突变体植株显著高于对照和CDD过表达植株,而过表达植株极显著低于对照及突变体。说明CDD过表达增强了杨树对干旱、高盐的敏感性,而敲除CDD后降低了杨树对干旱、高盐的敏感性。组织切片分析显示,在正常条件下木质部细胞层数呈现CDD过表达 > 对照84K > CDD缺失突变体,而在干旱、高盐条件下木质部细胞层数为CDD过表达 < 对照84K < CDD缺失突变体。表明CDD参与了木质部细胞分化过程,并当受到干旱、高盐胁迫时,CDD的表达对木质部分化过程的影响尤为明显。不定根数目统计显示,在正常条件和高盐条件下植株不定根数目呈现为CDD缺失突变体 > 对照84K > CDD过表达,且差异均达到显著水平或极显著水平,而干旱条件下差异不显著。表明CDD差异表达引起的不定根数目上的变化在一定程度上反映了杨树对干旱和高盐胁迫的敏感性。qRT-PCR分析显示,CDD过表达和CDD缺失突变体植株中均表现出多个PIP基因诱导高表达。表明CDD的表达变化可引起PIP基因不同成员的诱导表达,从而改变杨树的水分利用。[结论]杨树CDD的缺失或过量表达引起不定根数目的变化,同时改变了杨树的水分利用,影响对干旱和高盐胁迫的敏感性,导致胁迫下生长的变化。上述结果表明CDD参与杨树响应干旱和高盐胁迫过程。

关键词: CDD, 银腺杨84K, 干旱胁迫, 盐胁迫, 木质部, 不定根

Abstract: [Objective] Ca2+-dependent-deoxyribonuclease (CDD) can degrade ssDNA and dsDNA,however it is unclear that the function in response to drought and severe salt stresses.In this study,the role of CDD in growth and development of poplar trees (Populus alba×P.glandulosa ‘84K’) and the possible molecular mechanism in response to drought and salt stresses were analyzed,in order to provide a foundation for the elucidation of the regulatory role of CDD in stress tolerance of poplars.[Method] PtoCDD overexpressed and PagCDD knockout poplar lines (cuttings from tissue-cultured plants) were treated in drought and severe salt stresses and the phenotypes were accessed,including growth and adventitious rooting (AR).The anatomy of stem sections of transgenic lines and control plants (84K) were performed and the layers of xylem cells were compared.The expression of PIP in CDD transgenic poplar lines in response to drought and salt stresses were also analyzed by qRT-PCR.[Result] There were no significant differences between the transgenic poplar lines and the non-transgenic 84K in normal condition,while CDD knockout plants and CDD overexpressed plants respectively exhibited significantly higher and shorter than the control plants under the drought and salt stresses.This analysis indicated that CDD overexpression enhanced the sensitivity of poplars to the stresses.The anatomy analysis revealed that the layers of xylem cells were in the sequence of CDD overexpression lines > control 84K > CDD knockout lines from thick to thin in normal condition,while CDD knockout lines > control 84K > CDD overexpression lines under the stresses.The anatomy analysis demonstrated that the involvement of CDD in xylem differentiation was significantly affected by the stresses.In addition,the number of ARs exhibited CDD knockout lines > control 84K > CDD overexpression lines in the sequence from high to low,thus the CDD expression level could alter the number of ARs thus change the sensitivity of poplars in response to the stresses.qRT-PCR analysis showed that the expression of certain PIPs involved in responding to the the stresses were up-regulated in overexpression lines.This study demonstrated that CDD could induce the expression of certain PIP members to alter water usage.[Conclusion] Overexpression and knockout CDD could alter the expression of PIP,water usage,and the number of AR,of transgenic poplars,leading to the change in growth and development and the display of different sensitivity under the drought and salt stresses.Therefore,CDD is involved in the process of responding to the drought and salt stresses in poplars.

Key words: CDD, Populus alba×P, glandulosa ‘84K’, drought stress, salt stress, xylem, adventitious root

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