Page 85 - 《广西植物》2024年第12期
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12 期         赵娜红等: 油茶两个响应干旱 NAC 转录因子的克隆、亚细胞定位及自激活检测                                       2 2 4 3

                      ( 1. College of Forestryꎬ Jiangxi Agricultural Universityꎬ Nanchang 330045ꎬ Chinaꎻ 2. School of Nuclear Technology
                           and Chemical Biologyꎬ Hubei University of Science and Technologyꎬ Xianning 437100ꎬ Hubeiꎬ China)

                 Abstract: Drought stress is a major abiotic stress for the developmentꎬ yield and quality of Camellia oleifera. NAC
                 transcription factors play an important role in plant response to abiotic stresses such as drought and salinity. To explore
                 the role of NAC transcription factors in the drought stress response of C. oleiferaꎬ two ̄year oil tea seedlings were used as
                 materials. The CDS sequences of CoNAC5 and CoNAC79 were obtained from through TA cloning. Bioinformaticsꎬ
                 subcellular localization and self ̄activation were performed. qRT ̄PCR was used to determine the tissue specificity of
                 CoNAC5 and CoNAC79 gene expression and the expression PEG and ABA at different treatment time. The results were as
                 follows: (1) Gene structure analysis showed that length of CoNAC5 and CoNAC79 were 1 044 bp and 990 bpꎬ
                 respectivelyꎬ encoding 348 and 330 amino acids. Their theoretical isoelectric points were 8. 86 and 8. 57ꎬ
                 respectively. The instability coefficients of the proteins were 41.35 and 37.47ꎬ respectively. No transmembrane domain
                 was found between the two genesꎬ the highest homology with persimmon and lycheeꎬ respectively. Subcellular
                 localization showed that both CoNAC5 and CoNAC79 were located in the nucleus. (2) Yeast self ̄activation detection
                 analysis revealed that CoNAC5 and CoNAC79 did not have self ̄activation activity in the full ̄length proteins and N ̄
                 terminal domain. Howeverꎬ the C ̄terminal domain exhibited self ̄activation activity. (3) The expression of CoNAC5 and
                 CoNAC79 had significant tissue specificity and mainly expressed in roots and kernelsꎻ when PEG simulated drought and
                 exogenous ABA treated C. oleifera seedlingsꎬ the expression levels of CoNAC5 and CoNAC79 were significantly higher
                 than the controlꎻ the expression level of CoNAC79 decreased after 48 h under ABA treatmentꎬ and significantly higher
                 than the control under PEG treatment. In summaryꎬ it is believed that there may be an inhibitory region at the N ̄terminal
                 of CoNAC5 and CoNAC79ꎬ which hinders the transcription of the full ̄length sequenceꎻ indicating that the two NAC genes
                 in C. oleifera may be probably indirectly involved in drought stress response through pathway of ABA synthesisꎻ
                 CoNAC79 can also directly participate in the drought stress response through other pathways. This study provided a
                 scientific reference for further exploring the role of NAC transcription factors in the response of C. oleifera to drought
                 stress.
                 Key words: cloningꎬ drought stressꎬ subcellular localizationꎬ yeast self ̄activationꎬ ABA pathway




                  油 茶 ( Camellia oleifera )ꎬ 隶 属 于 山 茶 科       启下的作用(张幸媛等ꎬ2021)ꎮ
            (Theaceae)山茶属(Camellia L.)ꎬ是我国特有的木                     NAC 转录因子是植物特异性转录因子ꎬ其启
            本食用 油 料 树 种ꎮ 茶 油 单 不 饱 和 脂 肪 酸 高 达                 动子区富含低温、缺水、损伤等逆境响应元件( Han
            80%ꎬ具有 很 高 的 保 健 价 值ꎮ 油 茶 在 我 国 已 有                et al.ꎬ 2015)ꎮ 大量研究已证实ꎬNAC 转录因子参
            2 000多年的栽培历史ꎬ主要种植在我国长江流域                           与植物对干旱、冷害、低氧等非生物胁迫响应( Bu
            及其以南的山地、丘陵地区( 丁少净等ꎬ2017)ꎮ 干                        et al.ꎬ 2008)ꎮ 例如ꎬOsNAC2 / OsNAC6 基因的过表
            旱胁迫是影响植物生长发育的一类主要非生物胁                              达植株显著增强了水稻对干旱、盐分以及稻瘟病
            迫ꎮ 我国南方地区虽然降水量充沛ꎬ但是降水量                             的耐受力ꎬ其中干旱胁迫下过表达 OsNAC9 植株的

            在不同季节分配极度不均匀ꎬ5—6 月多雨ꎬ8—10                          籽粒 产 量 可 提 高 30% ( Liu et al.ꎬ 2016)ꎻ Hu 等
            月常出现季节性高温干旱天气( 何方ꎬ2011)ꎮ 民                         (2018)发现水稻 OsNAC1 能显著提高花期的抗旱

            间俗语“7 月干球ꎬ8 月干油”ꎬ指在每年阴历 7 到 9                      性ꎬ过表达植株结实率提高 22% ~ 34%且育性提高
            月是油茶果实膨大和种子油脂积累的关键时期ꎬ                              17% ~ 24%ꎻTakasaki 等(2010) 通过对水稻干旱胁
            而此时油茶主产区常出现持续干旱高温ꎬ导致油                              迫诱导ꎬ发现 OsNAC5 在过表达水稻中上调表达ꎬ
            茶产量及出油率大幅降低( 吴少强等ꎬ2022)ꎮ 当                         并通过上调胁迫诱导基因 OsLEA3 增强过表达植
            受到干旱胁迫时ꎬ植物会产生应答机制来减弱或                              株的抗旱性ꎮ 众多研究表明ꎬ脱落酸 ABA 作为一
            消除水分缺失造成的伤害ꎬ这一过程涉及多个基                              种植物胁迫激素ꎬ是植物应对干旱胁迫响应并及
            因、多种信号途径及代谢产物ꎬ其转录调控起承上                             时优化水分利用效率的重要调控因子( Huang et
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