Page 128 - 《广西植物》2026年第1期
P. 128

1 2 4                                  广  西  植  物                                         46 卷
                 Abstract: Glycerol ̄3 ̄phosphate acyltransferase (GPAT) plays essential roles in plant growth and development and
                 stress adaptation. To investigate the role of SmGPAT gene family members in Saussurea medusas adaptation to alpine
                 extremesꎬ we performed genome ̄wide identification using HMM and BLASTp methods and analyzed physicochemical
                 propertiesꎬ chromosome localizationꎬ gene structuresꎬ conserved motifsꎬ and cis ̄acting elements. We also examined
                 expression patterns across tissues using transcriptomic data and qRT ̄PCR validation. The results were as follows: (1) A
                 total of 15 SmGPAT family members were identified which randomly distributed on 10 chromosomes. These genes encoded
                 357-566 amino acid proteins (relative molecular mass of 40.16-63.86 kD) with isoelectric points of 5.93-10.02. Their
                 aliphatic index ranged from 79.56 to 104.60. Subcellular localization predictions indicated that the SmGPAT gene was
                 predominantly localized to mitochondria or the endoplasmic reticulum (except for SmGPAT7). (2) Phylogenetic analysis
                 divided SmGPATs into three subgroups (Group 1 - Group 3)ꎬ with members within subgroups shared similar gene
                 structures and conserved motifs. The secondary structure of SmGPAT family protein mainly contained α ̄helix and random
                 coilꎬ and the tertiary structure models were similar across subgroups. (3) The prediction analysis of cis ̄acting elements
                 revealed abundant stress ̄responsiveꎬ hormones ̄responsiveꎬ and light ̄responsive elements of SmGPAT family. ( 4)
                 Transcriptomic data analysis showed higher SmGPATs expression levels in leaf and flower than in stem and root. qRT ̄
                 PCR results were largely consistent with the transcriptomic results. In conclusionꎬ the expression patterns of the 15
                 SmGPAT family members indentified in S. medusa vary among different tissuesꎬ with higher expression levels in flower
                 and leaf. These findings suggest that SmGPAT members may play key roles in leaf and flower development in S.
                 medusa. This study provides a theoretical basis for further functional investigations of SmGPAT genes adapting to the
                 alpine extreme environment.
                 Key words: Saussurea medusaꎬ glycerol ̄3 ̄phosphate acyltransferase (GPAT)ꎬ gene familyꎬ bioinformatics analysisꎬ
                 tissue ̄specific expression




                甘油 ̄3 ̄磷酸酰基转移酶( glycerol ̄3 ̄phosphate             并不直接参与膜脂和油脂的合成ꎬ而是专注于陆
            acyltransferaseꎬ GPAT )  作 为 三 酰 甘 油               生植物所特有的角质和软木脂等胞外脂质的合成
            (triacylglycerolꎬTAG) 生物合成的关键限速酶ꎬ通                 ( Xu et al.ꎬ 2006ꎻ Li et al.ꎬ 2007)ꎮ 具 体 而 言ꎬ
            过催化甘油酯酰化反应的起始步骤调控代谢进程                              GPAT1 主 要 负 责 花 器 官 的 角 质 合 成ꎬ GPAT4、

            (Yang et al.ꎬ 2010)ꎮ 其催化机制包含催化甘油 ̄                  GPAT6 和 GPAT8 定位于内质网ꎬ并参与角质和蜡
            3 ̄磷酸 ( glycerol ̄3 ̄phosphateꎬG3P ) 与 脂 酰 基 结 合      质的合成( Zheng et al.ꎬ 2003)ꎮ GPAT4 和 GPAT8
            形成溶血磷脂酸(lysophosphatidic acidꎬLPA)ꎬ继而              协同参与拟南芥叶片和花序茎角质的合成( Li et

            由 LPA 酰基转移酶( LPA acyltransferaseꎬLPAAT)            al.ꎬ 2007)ꎬ而 GPAT6 也特异参与拟南芥花中角质
            催化生成磷脂酸( PA) ( 杨成兰ꎬ2022)ꎮ GPAT 具                   的合成ꎬ它们的突变体会影响花瓣的角质层厚度
            有独特的分子结构和活性调控ꎬ并在时间和空间                              和组分ꎬ进而影响植物的生长发育和抗逆性( 高华
            上呈现特定的分布ꎬ为多种脂质合成提供底物ꎬ参                             妮ꎬ2022)ꎮ 只有定位于内质网的 AtGPAT9 表现出
            与膜磷脂、糖脂、甘油三酯以及角质和软木脂等胞                             GPAT 酶活性ꎬ直接参与真核途径中的膜脂和油脂
            外脂质的生物合成( Wang et al.ꎬ 2020)ꎮ 这些脂                  的合成(Singer et al.ꎬ 2016)ꎮ 同时ꎬ质体中的可溶
            质在非生物胁迫信号的传递中发挥作用ꎬ并形成                              性酶 ATS1 利用脂酰基 ̄ACP 作为底物ꎬ催化甘油 ̄
            抵御病原体入侵的屏障ꎬ同时调节水分和溶质的                              3 ̄磷酸(G3P) 的 sn ̄1 位脂酰化ꎬ从而参与脂质合
            运输ꎬ在植物的生长、发育及逆境应对中具有重要                             成(Xu et al.ꎬ 2006ꎻ李昊根ꎬ2019)ꎮ 在水稻(Oryza
            功能(高森等ꎬ2018ꎻXin & Herburgerꎬ 2021)ꎮ                sativa)中ꎬGPAT 蛋白主要位于细胞膜部分ꎬ并参
                 目前ꎬ已在多个物种中开展了 GPAT 基因的研                       与去磷酸化、磷脂酰甘油、长链脂肪酸合成等多种
            究ꎬ在拟南芥(Arabidopsis thaliana)中将 GPAT 基因             脂质生物合成过程( Safderꎬ 2021)ꎮ 沙冬青的叶
            家族 根 据 亚 细 胞 定 位 的 差 异 划 分 为 GPAT1 -               绿体 GPAT 可以增加磷脂酰甘油中的不饱和脂肪
            GPAT8、GPAT9 和质体 ATS1 三类ꎮ GPAT1-GPAT8               酸水平(Xue et al.ꎬ 2019ꎻ杨成兰等ꎬ2022)ꎮ
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