BMC Genomics:中科院版纳植物园罗艳研究组揭示同一种植物为何会开

2016年5月20日，国际知名学术期刊《BMC Genomics》杂志上在线发表中国科学院西双版纳植物园植物进化生态学研究组的罗艳博士与美国北卡罗来纳大学夏洛特分校宋葆华博士等人合作的研究论文，研究结果题为Genome-wide analysis of gene expressionreveals gene regulatory networks thatregulate chasmogamous andcleistogamous flowering in Pseudostellaria heterophylla (Caryophyllaceae)。

闭花受精(Cleistogamy)植物具有非常特殊的繁育系统，有的闭花受精植物具有二型花，即同时具有正常开放可进行异交的开放花(chasmogamous flowers)和闭锁不开放进行自交的闭锁花(cleistogamous flowers)。植物产生闭锁花进行后代延续，是被子植物适应环境的一种非常有效的繁殖保障策略。闭锁花的产生与环境因素密切相关，一些闭花受精植物的闭锁花的产生往往与季节变换、生境改变相关。与正常的开放花相比，闭锁花在花构造上表现了不同程度的退化，例如花很小，无花瓣、雄蕊数目减少、子房数目减少等。开放花和闭锁花可在同一株植物产生，具有相同的遗传背景，花结构的改变与基因调控相关，是开展基因调控水平上控制花发育的分子机制研究的理想材料。

研究人员选用了二型闭花受精植物石竹科孩儿参(Pseudostellaria heterophylla)作为研究材料，采用转录组测序的研究方法，进行了两种孩儿参开放花与闭锁花的转录组比较分析。通过比较开放花和闭锁花不同花发育时期的花芽混合库的转录子，发现开放花和闭锁花芽中的一些花发育相关基因在转录水平上存在明显区别，例如FKF1、FT、STM、AP1、AP3、PI等基因，从而认为闭锁花的产生机制非常复杂，花发育调控网络中的一些基因在转录水平的改变与闭锁花的产生是相关的，例如调控植物节律的FKF1基因下调，光周期响应的成花素FT基因在闭锁花中下调，可能与营养器官向花器官发育过渡的过程相关;促进花分生组织形成的基因STM和花分生组织基因AP1在闭锁花中上调可能与分生组织产生花芽原基相关;被子植物花发育ABC模型中B类基因AP3和PI在闭锁花中下调，可能与闭锁花的花结构构建成相关。

Genome-wide analysis of GENE expression reveals gene regulatory networks that regulate chasmogamous and cleistogamous flowering in Pseudostellaria heterophylla (Caryophyllaceae)

原文摘要：

Background

Pseudostellaria heterophylla produces both closed (cleistogamous, CL) and open (chasmogamous, CH) flowers on the same individual but in different seasons. The production of CH and CL flowers might be in response to environmental changes. To better understand the molecular mechanisms of CH and CL flowering, we compared the transcriptome of the two types of flowers to examine differential gene expression patterns, and to identify gene regulatory networks that control CH and CL flowering.

Results

Using RNA sequencing, we identified homologues of 428 Arabidopsis genes involved in regulating flowering processes and estimated the differential gene expression patterns between CH and CL flowers. Some of these genes involved in gene regulatory networks of flowering processes showed significantly differential expression patterns between CH and CL flowers. In addition, we identified another 396 differentially expressed transcripts between CH and CL flowers. Some are involved in environmental stress responses and flavonoid biosynthesis.

Conclusions

We propose how the differential expression of key members of three gene regulatory modules may explain CH and CL flowering. Future research is needed to investigate how the environment impinges on these flowering pathways to regulate CH and CL flowering in P. heterophylla.

DOI: 10.1186/s12864-016-2732-0

作者：罗艳