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Article|01 Sep 2018|OPEN
An AGAMOUS-like factor is associated with the origin of two domesticated varieties in Cymbidium sinense (Orchidaceae)
Shihao Su1,2, Xiaoyu Shao1, Changfa Zhu1, Jiayin Xu1, Yuhuan Tang1, Da Luo1 & Xia Huang1,
1State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
2Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furocho, Chikusa-ku, Nagoya 464-8601 Aichi, Japan

Horticulture Research 5,
Article number: 48 (2018)
doi: 10.1038/hortres.2018.48
Views: 541

Received: 11 Nov 2017
Revised: 08 May 2018
Accepted: 17 May 2018
Published online: 01 Sep 2018

Abstract

Cymbidium has been artificially domesticated for centuries in Asia, which produced numerous cultivated varieties. Flowers with stamenoid tepals or those with multiple tepals have been found in different species of Cymbidium; however, the molecular basis controlling the formation of these phenotypes is still largely unknown. Previous work demonstrated that AGAMOUS/AG lineage MADS genes function in floral meristem determinacy as well as in reproductive organs development in both dicots and monocots, indicating a possible relationship with the origin of two flower varieties in Cymbidium. Here, we characterized and analyzed two AG lineage paralogues, CsAG1 and CsAG2, from Cymbidium sinense, both of which were highly expressed in the gynostemium column of a standard C. sinense. Interestingly, we detected ectopic expression of CsAG1 rather than CsAG2 in all floral organs of a stamenoid-tepal variety and significant down-regulation of CsAG1 in a variety with multiple tepals. Over-expression of CsAG1 in wild type Arabidopsis resulted in petal-to-stamen homeotic conversion, suggesting a conserved C-function of CsAG1 in the development of Cymbidium flower. Altogether, our results supported a hypothesis that disruption of a single AG-like factor would be associated with the formation of two domesticated varieties in C. sinense.