脱落酸和吡效隆对荔枝果皮着色的影响

Effect of abscisic acid and CPPU on the coloration of lychee pericarp

【目的】研究脱落酸(ABA)和吡效隆(CPPU)对荔枝果皮花色素苷生物合成及着色的影响,探索ABA调控荔枝果实花色素苷合成的分子机制。【方法】以‘桂味’荔枝为试材,喷施ABA和CPPU后,对果皮色泽、色素含量和花色素苷合成相关结构基因的表达规律进行分析。【结果】荔枝果实着色过程中,叶绿素含量降低,花色素苷含量增加,色度角逐渐降低;喷施ABA促进了花色素苷的积累,加速了叶绿素含量和色度角的降低,而CPPU则起了相反的作用;从花色素苷生物合成各基因的表达情况来看,对照果皮7个参试的结构基因均在果实成熟着色期间表达量逐步增加,而只有LcUFGT对ABA和CPPU两种生长调节剂的反应与果皮花色苷的积累趋势高度吻合,即ABA增加了LcUFGT的表达量,而CPPU明显抑制了LcUFGT的表达。【结论】ABA通过上调LcUFGT基因促进了荔枝果皮花色素苷的积累,加速了着色进程;而CPPU通过抑制LcUFGT基因的表达减缓了荔枝果皮花色素苷的合成,从而延缓荔枝果实着色;ABA参与了荔枝果皮中花色素苷生物合成调控,CPPU可能通过拮抗ABA影响花色苷的合成。

【Objective】 The effects of ABA and CPPU on fruit coloration and anthocyanin biosynthesis were explored and the possible molecular mechanism was discussed. 【Method】 Lychee cultivar ‘Guiwei'was used as material. The color parameters, contents of pigments and the expressions of structural genes in anthocyanin biosynthesis in response to ABA and CPPU treatments were analyzed. 【Results】 Contents of chlorophylls and hue angle decreased gradually, while contents of anthocyanin increased with fruit coloration. ABA treatment promoted the accumulation of anthocyanins and accelerated the reduction of chlorophyll content and hue angle, whereas CPPU treatment displayed opposite effects. The expressions of the seven structural genes tested in the pericarp of control were all up regulated in paralleling fruit coloration and anthocyanin accumulation. However, only the expressions of LcUFGT in the pericarp of ABA and CPPU treatments were generally agreed with the changes of anthocyanins. ABA treatment enhanced,while CPPU treatment postponed the expression of LcUFGT. 【Conclusion】 ABA promoted anthocyanin accumulation in pericarp of lychee and accelerated coloring process by increasing expression level of LcUFGT while CPPU delayed the coloration of the lychee fruit through inhibiting the biosynthesis of anthocyanin. ABA might play an important role in regulation of anthocyanin biosynthesis, while CPPU played its role by antagonizing ABA.