摘要
黄梁木(Neolamarckia cadamba)是富含药用活性成分的常绿速生乔木,在传统医学、木材及造林等领域具有广泛用途。MYC转录因子属于bHLH转录因子家族,在植物逆境响应、激素信号传导、调节植物次生代谢产物生物合成等方面发挥重要作用。为了探究黄梁木NcMYC2的功能,本研究克隆了NcMYC2基因,分析了其在不同生理年龄、不同逆境和激素刺激下的表达模式,并初步探索了其功能。结果显示:黄梁木NcMYC2全长cDNA序列长度为2297 bp,开放阅读框(ORF)长度为1578 bp,编码526个氨基酸。该基因包含bHLH_AtAIB_like和bHLH-MYC_N两个保守结构域,与巴西橡胶(Hevea brasiliensis)的HbMYC2亲缘关系最近。NcMYC2蛋白定位于细胞核,且在酵母中具有转录活性。NcMYC2启动子顺式作用元件包含多个光、激素及胁迫响应元件。表达分析结果显示,NcMYC2在黄梁木不同发育时期各器官中都有表达,且在叶中表达量最高;1 mmol·L^(-1)茉莉酸甲酯(MeJA)刺激下,NcMYC2主要在叶中表达并在24 h达到峰值;10 mg·L^(-1)脱落酸(ABA)能促进Nc MYC2在叶中表达,而100 mg·L^(-1) ABA则抑制NcMYC2的表达;在100 mmol·L^(-1) NaCl盐胁迫下,NcMYC2主要在根中响应,表达水平呈现先升后降的趋势。在拟南芥中超表达NcMYC2能提高种子在盐胁迫下的萌发率,并增强幼苗的抗盐性。以上结果证明NcMYC2在黄梁木的抗盐胁迫中发挥重要作用。
Neolamarckia cadamba is an evergreen fast-growing tree rich in medicinally active ingredients,which is widely used in traditional medicine,timber production and afforestation.MYC transcription factors,belonging to the bHLH transcription factor family,play significant roles in plant stress responses,hormone signaling transduction,and the regulation of plant secondary metabolite biosynthesis.In order to explore the function of NcMYC2 in N.cadamba,the study cloned the NcMYC2 gene,analyzed its expres sion patterns under different physiological ages,abiotic stresses and hormone treatments and preliminarily explored its biological role.The results showed that the full-length cDNA sequence of NcMyC2 was 2297 bp,containing an open reading frame(ORF)of 1578 bp that encodes 526 amino acids.This gene contains two conserved domains,bHLH_AtAIB_like and bHLH-MYC_N,and shares the closest phylogenetic relationship with HbMYC2 of Hevea brasiliensis.The NcMYC2 protein was localized in the nucleus and exhibited transcriptional activity in yeast.The NcMYC2 promoter contained multiple cis-acting elements involved in light,hormonal,and stress responses.The results of expression analysis revealed that NcMYc2 was expressed in all organs across different developmental stages,with the highest transcript level in leaves.Under 1 mmol·L^(-1) methyl jasmonate(MeJA)treatment,NcMYC2 expression was predominantly induced in leaves and peaked at 24 h.Treatment with 10 mg.L^(-1) abscisic acid(ABA)promoted the expression of NcMYC2 in leaves,whereas 100 mg·L^(-1) ABA suppressed it.Under 100 mmol·L^(-1) NaCl salt stress,NcMyc2 responded mainly in roots,exhibiting an expression pattern that initially increased and then decreased overexpression of NcMYc2 in Arabidopsis thaliana significantly improved seed germination rates under salt stress and enhanced the salt tolerance of seedlings.These results demonstrated that NcMYc2 played a crucial role in the salt stress response of N.cadamba.
作者
邓美欣
吴奇轩
龙健梅
许佐威
彭昌操
张建霞
DENG Meixin;WU Qixuan;LONG Jianmei;XU Zuowei;PENG Changcao;ZHANG Jianxia(College of Forestry and Landscape Architecture,South China Agricultural University,Guangzhou 510630,China;Key Laboratory of Forest Plant Germplasm Innovation and Utilization,Guangzhou 510630,China)
出处
《植物生理学报》
北大核心
2026年第1期82-98,共17页
Plant Physiology Journal
基金
广东省自然科学基金(2023A1515010341)。
关键词
黄梁木
NcMYC2
表达分析
盐胁迫
功能
Neolamarckia cadamba
NcMYC2
expression analysis
salt stress
function
