昨日，南京林业大学林学院苑兆和教授课题组完成题为“ARF6s identification and function analysis provide insights into flower development of Punica granatum L.”的研究论文在线发表于国际知名期刊Frontiers in Plant Science（IF=5.753）。

摘要：Based on the genome and small-RNA sequencing of pomegranate, miRNA167 and three target genes PgARF6 were identified in “Taishanhong” genome. Three PgARF6 genes and their corresponding protein sequences, expression patterns in pomegranate flower development and under exogenous hormones treatments were systematically analyzed in this paper. We found that PgARF6s are nuclear proteins with conserved structures. However, PgARF6s had different protein structures and expression profiles in pomegranate flower development. At the critical stages of pomegranate ovule sterility (8.1–14.0 mm), the expression levels of PgARF6s in bisexual flowers were lower than those in functional male flowers. Interestingly, PgARF6c expression level was significantly higher than PgARF6a and PgARF6b. Under the treatment of exogenous IBA and 6-BA, PgARF6s were down-regulated, and the expression of PgARF6c was significantly inhibited. PgmiR167a and PgmiR167d had the binding site on PgARF6 genes sequences, and PgARF6a has the directly targeted regulatory relationship with PgmiR167a in pomegranate. At the critical stage of ovule development (8.1–12.0 mm), exogenous IBA and 6-BA promoted the content of GA and ZR accumulation, inhibited BR accumulation. There was a strong correlation between the expression of PgARF6a and PgARF6b. Under exogenous hormone treatment, the content of ZR, BR, GA, and ABA were negatively correlated with the expressions of PgARF6 genes. However, JA was positively correlated with PgARF6a and PgARF6c under IBA treatment. Thus, our results provide new evidence for PgARF6 genes involving in ovule sterility in pomegranate flowers.

与ARF6基因 

基于‘泰山红’石榴基因组和small RNA测序数据，作者在‘泰山红’石榴基因组中鉴定出3个ARF6同源基因及两个PgmiRNA167成员。

石榴、巨桉、杨、拟南芥等物种ARF基因家族系统发育树

基因和蛋白结构分析发现，石榴三个ARF6序列存在不等数目的蛋白插入或删除，并且其蛋白三级结构中3-10-Helix的位置存在差异，蛋白结构差异与后期分析发现石榴ARF6同源基因表达模式不同的结果一致。

基于石榴不同组织的转录组数据分析表明，PgARF6在石榴花中表达量高于根、果皮、叶片组织，且完全花表达量显著高于不完全花，说明ARF6参与调控石榴花器官发育。亚细胞定位结果发现，三个PgARF6蛋白均定位在细胞核，表明其在细胞核内行使功能。

石榴ARF6蛋白序列比对和三级结构分析

作者进一步分析石榴完全花和不完全花不同发育过程及外源激素处理下PgARF6成员基因的表达模式。在石榴花发育过程中，PgARF6c表达量显著高于PgARF6a和PgARF6b；通过对miRNA靶基因预测和组学测序数据分析，明确石榴ARF6a与miRNA167存在靶向调控关系，然而ARF6b、ARF6c与miRNA167在转录水平不存在直接的靶向关系。在外源IBA和6-BA处理下，石榴花发育过程中PgARF6表达被抑制，内源激素IAA、ZR、BR、GA及ABA含量均不同程度地响应外源激素处理。在外源激素处理下，内源激素ZR、BR、GA及ABA含量与PgARF6表达量呈负相关；但外源IBA处理下，内源JA含量与PgARF6表达正相关。

外源IBA和6-BA处理下内源激素含量与PgARF6基因表达量的相关性

作者进一步对研究结果进行了总结凝练，表明ARF6基因、miRNA167及内源激素参与调控石榴花发育，初步证明ARF6基因参与石榴花雌蕊败育，为阐明石榴不完全花雌蕊败育机理奠定基础。

相关文章链接

相关文献1：

石榴花器官发育相关基因PgWUS和PgBEL1克隆及其时空表达分析. （https://www.ahs.ac.cn/CN/10.16420/j.issn.0513-353x.2020-0377）

相关文献 2：

Variation of endobenous phytohormone in functional male and bisexual flowers of pomegranate (Punica granatum L.) during development. （http://dx.doi.org/10.30848/PJ B2021-2(12)）

相关文献3：

Genome-wide identification and expression of YABBY genes family during flower development in Punica granatum L. （https://doi.org/10.1016/j.gene.2020.144784）

相关文献4：

Genome-wide identification and expression analysis of MIKC-type MADS-box gene family in Punica granatum L. （https://doi.org/10.3390/agronomy10081197）

相关文献5：

园艺植物性别决定机制研究进展. （https://www.ahs.ac.cn/CN/Y2018/V45/I11/2228）