张树伟 彭宏祥

摘 要：‘GL为‘禾荔中选育出的一个优质晚熟芽变新种质。为探讨‘GL果实成熟期延迟的遗传基础，该研究以‘禾荔和‘GL为实验材料，克隆花色素苷合成途径结构基因LcUFGT，并对其进行生物信息学预测及分析，同时通过qRT-PCR对LcUFGT基因在果实发育不同阶段的表达进行研究，分析LcUFGT的表达对突变体果实发育速度的影响。结果表明：（1）LcUFGT基因ORF长1 359 bp，编码453个氨基酸，推测蛋白质分子量约为50.16 kD。（2）序列比对发现所编码蛋白与‘禾荔等荔枝品种高度保守，在蛋白的C端具有PSPG盒。（3）在果实发育成熟进程中，‘禾荔和‘GL果皮逐渐退绿转红，两者LcUFGT基因的表达量都呈先上升后下降的表达趋势，然而，‘禾荔 LcUFGT基因的表达量在花后56 d显著增加，突变体‘GL LcUFGT基因的表达量在花后67 d显著增加，LcUFGT基因在突变体‘GL中显著上升表达的时间比‘禾荔延迟，且与果实发育延迟基本一致。以上结果表明，LcUFGT基因在荔枝果皮着色过程中发挥重要作用，是果实着色的关键基因之一，突变体‘GL中的延迟表达是引起突变体晚熟的原因之一。

关键词：晚熟突变体，LcUFGT基因，果实发育，花色素苷合成，表达分析

中图分类号：Q943文献标识码：A

文章编号：1000-3142（2020）01-0128-08

Abstract：‘GL is an excellent late-maturing bud sport germplasm，which was selected from ‘Heli. To reveal the genetic basis of late-maturing，in this study，‘Heli and ‘GL were used as the materials. The LcUFGT which is a structural gene of anthocyanin synthesis pathway was cloned and analyzed by bioinformatic methods. The corelation between LcUFGT and the character of late-maturing in ‘GL and  the expression of LcUFGT during the development of litchi fruit were analyzed by qRT-PCR. The results were as follows：（1） ORF of LcUFGT gene was 1 359 bp，which encoded 453 amino acids with the molecular weight of 50.16 kD. （2） LcUFGT gene was conservative in ‘GL and other litchi cultivars，and a PSPG box existed in the C-terminal. （3） With the development of litchi fruit，the color of pericarp began to turn from green to red; the expression of LcUFGT was increased and then decreased in both ‘GL and ‘Heli; the expression of LcUFGT was obviously increased at 56 d and 67 d after flowering of ‘Heli and ‘GL，respectively; the expression of LcUFGT had a delayed increase in ‘GL than that of ‘Heli，which was consistent with the late-maturing of fruits. It is supposed that LcUFGT plays an important role in color changes of pericarp，and it is one of the key genes to regulate coloration of pericarp. At the same time，the delay-expression of LcUFGT maybe the main reason of late-maturing of ‘GL.

Key words：late maturity mutant，LcUFGT，fruit development，anthocyanin synthesis，expression analysis

荔枝（Litchi chinensis）是我國华南地区种植面积最大的木本果树，是华南地区农民经济收入的主要来源之一。目前，生产上缺乏特早熟和特晚熟优质荔枝品种，造成荔枝集中在六七月份成熟上市，产期过于集中，造成农民丰产而不丰收。‘禾荔是广西传统的栽培品种，品质优良，并且丰产、稳产，突变体‘GL不仅保留了‘禾荔的优良特性，而且成熟期延迟，较‘禾荔晚熟15 d（李平等，2016），是调节荔枝品种栽培结构拉长鲜果供应期的优异资源，同时也是荔枝熟期育种及果实发育理论研究的重要材料。……