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从杭白菊(Chrysanthemum morifolium‘Hangbaiju’)中克隆了4个细胞壁松弛和伸展相关的木葡聚糖内转糖苷酶/水解酶基因,分别命名为CmXTH1、CmXTH2、CmXTH3和CmXTH4,序列分析表明其编码的氨基酸序列N端都含有23~30个氨基酸组成的信号肽区域和保守的催化活性位点DE(I/L)DEFLG以及紧邻的N(R/A)T组成的N端糖基化位点,CmXTH1/2/3的C端均含有4个保守的半胱氨酸残基,CmXTH1/2/3/4蛋白的相似度为66.2%。系统进化分析结果表明,CmXTH1/2/3属于XTH家族Ⅰ组,CmXTH4属于Ⅱ组。实时荧光定量结果表明:(1)菊花CmXTH1/2/3/4在根、茎、叶和花蕾中均有表达。CmXTH1在根中表达量较高,CmXTH2/3在茎中表达量较高,CmXTH4在花蕾中表达量最高。(2)CmXTH1/2/3/4在花序不同部位表达量有差异,CmXTH1/4在舌状花中表达量最高,CmXTH2/3在筒状花中表达量较高。(3)CmXTH1/2/3/4在舌状花不同发育阶段表达量差异显著,CmXTH1/2在盛花期表达量最高,CmXTH3在衰老期表达量最高,CmXTH4在初开期表达量最高。病毒诱导基因沉默结果表明,CmXTH1/2/3/4沉默系的花序直径和舌状花长度与对照相比均有所减小,其中CmXTH4沉默系减小最大,分别减小了25.67%和10.42%,舌状花花瓣表皮细胞与对照相比明显变小,影响了舌状花花瓣的伸长;CmXTH2沉默系的筒状花雄蕊长度和CmXTH4沉默系的花萼直径分别与对照相比显著减小。这表明菊花CmXTH1/2/3/4基因参与了花序的开放,促进了舌状花花瓣的伸长,对于菊花的花序增大具有重要作用。
Four xyloglucan endotransglucosidase / hydrolase genes related to cell wall relaxation and elongation were cloned from Chrysanthemum morifolium’Hangbaiju ’and named as CmXTH1, CmXTH2, CmXTH3 and CmXTH4 respectively. Sequence analysis showed that their coding Of the N-terminal glycosylation site consisting of a signal peptide region consisting of 23 to 30 amino acids at the N-terminus of the amino acid sequence and a conserved catalytic site DE (I / L) DEFLG and immediately adjacent N (R / A) T There were four conserved cysteine residues in the C terminus of CmXTH1 / 2/3, and the similarity of CmXTH1 / 2/3/4 protein was 66.2%. Phylogenetic analysis showed that CmXTH1 / 2/3 belongs to the XTH family Ⅰ group, and CmXTH4 belongs to the group Ⅱ. Real-time fluorescence quantitative results showed that: (1) Chrysanthemum CmXTH1 / 2/3/4 expressed in roots, stems, leaves and buds. CmXTH1 was higher in roots, CmXTH2 / 3 was higher in stems, and CmXTH4 was highest in buds. (2) The expression of CmXTH1 / 2/3/4 was different in different parts of inflorescence. CmXTH1 / 4 was the highest expression in the tongue flowers and CmXTH2 / 3 was higher in the tubular flowers. (3) The expression of CmXTH1 / 2/3/4 was significantly different in different developmental stages of tongue flower. CmXTH1 / 2 was the highest expression at full flowering stage, CmXTH3 was highest at senescence stage, and CmXTH4 was the highest at early opening stage. The result of virus-induced gene silencing showed that the diameter of inflorescence and the length of tongue-shaped flower of CmXTH1 / 2/3/4 silencing lines decreased compared with the control, and the silencing system of CmXTH4 decreased the most, which decreased by 25.67% and 10.42 %, The tongue flower petal epidermal cells were significantly smaller than the control, affecting the elongation of the tongue flower petals; CmXTH2 silenced tube length of the flower stamens and CmXTH4 silent calyx diameter were significantly reduced compared with the control . This indicates that the chrysanthemum CmXTH1 / 2/3/4 gene is involved in the opening of the inflorescence and promotes the elongation of the petal of the flower, which plays an important role in the inflorescence of the flower.