董晨 魏永赞 王弋 郑雪文 李伟才

摘 要： 木葡聚糖内切葡聚糖酶/水解酶（xyloglucan endotransglucosylase/hydrolase，XTH）是一类重要的糖苷水解酶，在促进植物细胞壁延展以及响应逆境胁迫方面发挥着重要作用。为研究荔枝XTH家族基因在不同花穗处理方式下的表达情况，该文以‘妃子笑荔枝为实验材料，对‘妃子笑花穗进行疏花和喷施烯效唑处理;基于前期转录组数据库鉴定出29个LcXTH家族成员，利用荧光定量PCR（RT-qPCR）技术对LcXTH基因家族成员在不同处理后花穗的表达进行研究，分析XTH家族基因对不同花穗处理方式的响应情况。结果表明：LcXTH家族基因成员表达在对照、疏花处理和烯效唑处理后花穗不同发育阶段表达规律不同，且不同基因存在表达量的差异。其中LcXTH 亚家族Ⅲ、LcXTH 亚家族Ⅳ（LcXTH2、LcXTH3、LcXTH4、LcXTH5、LcXTH6、LcXTH7、LcXTH9、LcXTH10、LcXTH11、LcXTH12、LcXTH13、LcXTH22和LcXTH23）成员及LcXTH20表达量较高，推测在花穗发育中起关键作用。‘妃子笑花穗疏花处理14 d后LcXTH家族大部分成员表达上调，推测疏花对LcXTH的表达起到正调控作用;‘妃子笑花穗喷施烯效唑后LcXTH家族成员的表达下调，推测烯效唑处理对LcXTH的表达起到负调控作用。

关键词： 荔枝， 不同处理， XTH基因家族， RT-qPCR， 基因表达

中图分类号： Q943

文献标识码： A

文章编号： 1000-3142（2021）04-0514-08

Abstract： Xyloglucan endotransglucosylase/hydrolase （XTH） is an important class of glycoside hydrolase that plays an important role in promoting plant cell wall elongation and responding to stress. In order to study the expression of the XTH family genes in different inflorescence treatments， 29 LcXTH family members were identified with ‘Feizixiao litchi as the experimental material， based on the pre-transcriptome database. The inflorescences of litchi were treated with flower thinning and uniconazole treatment， respectively. Expressions of LcXTH gene family members in different inflorescences were studied by real-time PCR （RT-qPCR）， and the response of LcXTH family genes to different inflorescence treatments were analyzed. The results showed that the expressions of LcXTH family members were different in the different flower developmental stages after control， flower thinning treatment and uniconazole treatment， and there are differences in the expression levels of different genes. Among them， members of LcXTH subfamily Ⅲ， LcXTH subfamily Ⅳ （LcXTH2， LcXTH3， LcXTH4， LcXTH5， LcXTH6， LcXTH7， LcXTH9， LcXTH10， LcXTH11， LcXTH12， LcXTH13， LcXTH22 and LcXTH23） and LcXTH20 had higher expression levels， presumably it plays a key role in flower development. LcXTH expression was up-regulated at the 14 d after flower thinning， and we speculated flower thinning had a positive regulation effect on LcXTH. Uniconazole treatment inhibited the expression of LcXTH and negatively regulated LcXTH.

Key words： litchi， different treatments， XTH gene family， RT-qPCR， gene expression

荔枝是原產于中国重要的热带亚热带水果，目前荔枝产业已成为中国南方热作区的支柱产业之一，在农村经济的发展及热区果农收入水平的提高方面发挥着举足轻重的作用。‘妃子笑荔枝花穗具有花穗长、花量大等特点，生产上需要对荔枝的花穗进行调控处理提高坐果，调控措施通过机械疏花或是化学调控。……