Double-flower loquat (Eriobotrya japonica) is a new germplasm with homeotic transformation of stamen into petal in whorl 3. However, little information is available on the molecular mechanism of this transformation. Herein, we analyzed the transcriptome, candidate genes and endogenous hormones to investigate the mechanisms underlying this homeotic transformation. Some transcription factors, such as MADS-box, TCP and MYB, were significantly differentially expressed. Importantly, we confirmed that one of these (DN39625_c0_g1), which encoded a C-class floral homeotic protein referred to as AGAMOUS ortholog (EjAG), was significantly downregulated. Subcellular localization of EjAG was found to be in the nucleus. Ectopic expression of EjAG rescued the development of stamens and carpels from the double-flower phenotype in an Arabidopsis ag mutant, suggesting that EjAG expression is associated with double-flower formation. Meanwhile, enrichment analyses showed that the differentially expressed genes (DEGs) were mainly involved in the metabolic pathways of hormone signal transduction. The DEGs of auxin, gibberellin A (GA) and cytokinin signaling pathways were mainly upregulated. However, the DEGs of abscisic acid (ABA) and the ethylene signaling pathway were mainly downregulated. Accordingly, the concentrations of indoleacetic acid, kinetin and GA3 were high at the petaloid stamen stage, but the ABA concentration remained low. The identified genes and pathways provide abundant sequence resources for studying the mechanisms underlying the homeotic transformation in loquat and other Rosaceae species. This article is protected by copyright. All rights reserved.

中文翻译：

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枸杞雄蕊向花瓣的同种异型转化与激素信号转导和EjAG转录活性降低有关

重瓣枇杷（Eriobotrya japonica）是一种新种质，在轮3中雄蕊向花瓣的同源转化。然而，关于这种转化的分子机制的信息很少。在此，我们分析了转录组、候选基因和内源性激素，以研究这种同源异型转化的机制。一些转录因子，如 MADS-box、TCP 和 MYB，存在显着差异表达。重要的是，我们证实其中一个（DN39625_c0_g1）编码了一种被称为 AGAMOUS 直向同源物（EjAG）的 C 级花卉同源异位蛋白，被显着下调。发现 EjAG 的亚细胞定位在细胞核中。EjAG 的异位表达从拟南芥 ag 突变体的双花表型中拯救了雄蕊和心皮的发育，表明 EjAG 表达与双花形成有关。同时，富集分析表明差异表达基因（DEGs）主要参与激素信号转导的代谢途径。生长素、赤霉素A（GA）和细胞分裂素信号通路的DEGs主要上调。然而，脱落酸（ABA）的DEGs和乙烯信号通路主要被下调。因此，在花瓣状雄蕊阶段，吲哚乙酸、激动素和GA3的浓度较高，而ABA浓度仍然较低。鉴定出的基因和通路为研究枇杷和其他蔷薇科物种同源异型转化的机制提供了丰富的序列资源。本文受版权保护。版权所有。