生物技术通报 ›› 2025, Vol. 41 ›› Issue (8): 267-275.doi: 10.13560/j.cnki.biotech.bull.1985.2025-0388

• 研究报告 • 上一篇    

红肉火龙果细胞壁转化酶基因SmCWIN6的表达和酶活性鉴定

郑乾明1,2(), 晏霜1,3, 解璞1, 王红林1,2   

  1. 1.贵州省农业科学院贵州省果树科学研究所,贵阳 550006
    2.贵州省农业科学院农业农村部喀斯特山区作物基因资源与种质创新重点实验室,贵阳 550006
    3.贵州省特色园艺作物分子育种全省重点实验室,贵阳 550006
  • 收稿日期:2025-04-13 出版日期:2025-08-26 发布日期:2025-08-14
  • 作者简介:郑乾明,男,博士,副研究员,研究方向 :园艺果实品质形成机理;E-mail: zqm851015@163.com
  • 基金资助:
    国家自然科学基金项目(32060674);贵州省科技计划(黔科合服企[2024]003-1);贵州省科技计划(黔科合平台[2025]027)

Expression and Enzyme Activity Identification of Cell Wall Invertase Gene SmCWIN6 from Red Pitaya

ZHENG Qian-ming1,2(), YAN Shuang1,3, XIE Pu1, WANG Hong-lin1,2   

  1. 1.Guizhou Institute of Pomology Science, Guizhou Academy of Agricultural Sciences, Guiyang 550006
    2.Key Laboratory of Crop Genetic Resources and Germplasm Innovation in Karst Region, Ministry of Agriculture and Rural Affairs, Guizhou Academy of Agricultural Sciences, Guiyang 550006
    3.Guizhou Key Laboratory of Molecular Breeding for Characteristic Horticultural Crops, Guiyang 550006
  • Received:2025-04-13 Published:2025-08-26 Online:2025-08-14

摘要:

目的 细胞壁转化酶(cell wall invertase, CWIN)分解蔗糖生成葡萄糖和果糖,是高等植物糖代谢关键酶。探讨CWINs在红肉火龙果(Selenicereus monacanthus)果实可溶性糖代谢中的生理功能,为调控和改良果实风味和品质提供基础。 方法 提取成年态茎和各发育时期果肉的总蛋白,检测CWIN酶活性,分析SmCWIN家族序列结构域,利用基因数字表达谱和实时荧光定量PCR检测SmCWINs在花、茎、果皮和果肉中的表达模式,通过瞬时转化烟草叶肉细胞进行SmCWIN6的亚细胞定位,利用酿酒酵母表达并提取总蛋白,离体检测SmCWIN6的酶活性。 结果 红肉火龙果成年态茎的CWIN酶活性较低,在果实授粉后23 d时最高,此后,随果实成熟明显下降。红肉火龙果SmCWIN家族仅SmCWIN6含有蔗糖分解相关的结构域和保守的氨基酸残基。SmCWIN6在果实中表达,主要在授粉后20-25 d表达,此后,随果实发育逐渐下调表达,果实成熟时(授粉后30 d)表达微弱。亚细胞定位结合质壁分离试验表明,SmCWIN6蛋白定位于质外体,可能位于细胞壁。经酵母表达获得重组蛋白并离体检测,SmCWIN6可分解蔗糖产生葡萄糖和果糖,在pH = 3.0具有最大酶活性。 结论 SmCWIN6在质外体分解蔗糖产生葡萄糖和果糖,主要在果实授粉后20-25 d表达,参与果实发育期间胞外可溶性糖代谢。

关键词: 火龙果, 细胞壁转化酶, 质外体, 酵母表达, 蔗糖分解

Abstract:

Objective Cell wall invertase (CWIN) degrades sucrose into glucose and fructose, and acts as the key enzyme for sugar metabolism in higher plants. The physiological functions of CWINs in soluble sugar metabolism of red pitaya (Selenicereusmonacanthus) fruit were investigated, which provides a basis for regulating and improving fruit flavor and quality. Method Total protein from adult stem tissues and fruit pulp at various developmental stages was extracted to detect the CWIN enzyme activity; the sequence domains of SmCWIN family were analyzed; the expression patterns of SmCWINs in flower, stem, fruit peel and pulp tissues were detected by gene digital expression profiles and real-time fluorescent quantitative PCR. The subcellular localization of SmCWIN6 was detected by transiently transformed in tobacco mesophyll cells. By expressed in the baker’s yeast (Saccharomyces cerevisiae) and then total protein was extracted, the enzyme activity of SmCWIN6 was analyzed in vitro. Result The CWIN enzyme activity in adult stems of red pitaya was low, reached highest at 23 d after pollination in fruit, and then decreased significantly with fruit ripening. Of the red pitaya SmCWIN family, only SmCWIN6 contained domains and conserved amino acid residues related to sucrose degradation. SmCWIN6 was the only CWIN member that expressed in fruits and mainly expressed at 20-25 d after pollination; after then gradually down-regulated with fruit development, and weakly expressed at fruit ripening (30 d after pollination). Subcellular localization assay together with the plasmolysis experiment showed that SmCWIN6 protein was located into the apoplast space, possibly in the cell wall. After been expressed by yeast cells and detected in vitro, the SmCWIN6 protein degraded sucrose into glucose and fructose with the maximum enzyme activity at pH=3.0. Conclusion Red pitaya SmCWIN6 degrades sucrose to produce glucose and fructose in the apoplast, is expressed at 20-25 d after pollination in fruits, and involved in the extracellular soluble sugars metabolism during fruit development.

Key words: pitaya, cell wall invertase, apoplast, yeast expression, sucrose degradation