Main conclusionUsing RNA-Seq, we identified genes involved in floral development in lavenders and functionally characterized the floral repressor LaSVP.AbstractThe molecular aspects of flower initiation and development have not been adequately investigated in lavender (Lavandula). In order to identify genes that control these processes, we employed RNA-Seq to obtain sequence information for transcripts originating from the vegetative shoot apical meristem (SAM) and developing inflorescence tissues of Lavandula angustifolia and Lavandula × intermedia plants, and assemble a comprehensive transcriptome of 105,294 contigs. Homology-based annotation provided gene ontology terms for the majority of transcripts, including over 100 genes homologous to those that control flower initiation and organ identity in Arabidopsis thaliana. Expression analysis revealed that most of these genes are differentially expressed during flower development. For example, LaSVP, a homolog of the floral repressor SHORT VEGETATIVE PHASE (SVP), was strongly expressed in vegetative SAM compared to developing flowers, implicating its potential involvement in flowering repression in lavender. To investigate LaSVP further, we constitutively expressed the gene in transformed A. thaliana plants, evaluating its effects on flower initiation and morphology. Expression of the LaSVP in A. thaliana delayed flowering and affected flower organ identity in a dosage-dependent manner. Two of the highest expressing lines produced sepals instead of petals and were sterile as they failed to develop proper seed pods. This study provides the foundation for future investigations aimed at elucidating flower initiation and development in lavender.

中文翻译：

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薰衣草花抑制基因的克隆和功能表征

主要结论使用 RNA-Seq，我们鉴定了参与薰衣草花发育的基因，并对花抑制因子 LaSVP 进行了功能表征。为了鉴定控制这些过程的基因，我们使用 RNA-Seq 来获取源自营养枝顶端分生组织 (SAM) 和发育中的薰衣草和薰衣草 × 中间植物的花序组织的转录物的序列信息，并组装了一个全面的转录组： 105,294 个重叠群。基于同源性的注释为大多数转录本提供了基因本体术语，包括 100 多个与拟南芥中控制花起始和器官同一性的基因同源的基因。表达分析表明，这些基因中的大多数在花发育过程中都有差异表达。例如，与发育中的花相比，花抑制因子 SHORT VEGETATIVE PHASE (SVP) 的同源物 LaSVP 在营养 SAM 中强烈表达，暗示其可能参与薰衣草的开花抑制。为了进一步研究 LaSVP，我们在转化的拟南芥植物中组成性地表达了该基因，评估了它对花起始和形态的影响。LaSVP 在拟南芥中的表达延迟开花并以剂量依赖性方式影响花器官特性。两个表达率最高的品系产生萼片而不是花瓣并且是不育的，因为它们未能发育出适当的种子荚。