1. B and E MADS-box genes determine the perianth formation in Cymbidium goeringii Rchb.f
- Author
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Liping Chen, Yue Chen, Kaige Zhao, Jie Zhang, Lin Xiang, Chongbo Sun, and Xiaopeng Fu
- Subjects
0106 biological sciences ,0301 basic medicine ,Physiology ,MADS Domain Proteins ,Plant Science ,Flowers ,01 natural sciences ,Sepal ,03 medical and health sciences ,Gene Expression Regulation, Plant ,Complementary DNA ,Botany ,Genetics ,Cymbidium goeringii ,Orchidaceae ,MADS-box ,Phylogeny ,Gene Library ,Plant Proteins ,biology ,Models, Genetic ,Gene Expression Profiling ,fungi ,Cell Biology ,General Medicine ,biology.organism_classification ,030104 developmental biology ,Petal formation ,Petal ,Perianth ,Homeotic gene ,010606 plant biology & botany ,Protein Binding - Abstract
Cymbidium goeringii Rchb.f. is an important ornamental plant with a striking well-differentiated lip. Its complex floral architecture presents an exciting opportunity to examine perianth development. In flowering plants, class A, B and E floral homeotic genes play key roles in the specification of perianth identity. In this study, we used a cDNA library of wild-type C. goeringii flower buds for transcriptome sequencing. Eighteen candidate class A, B and E genes (including AP1/FUL-, AP2-, DEF-, GLO-, SEP- and AGL6-like genes) were identified. Quantitative real time polymerase chain reaction (qRT-PCR) results showed that CgDEF1, CgSEP2 and CgAGL6-1 were strongly detected only in the sepals and petals and were significantly downregulated in the lips. CgDEF3, CgDEF4 and CgAGL6-3 were highly expressed in the lips and lip-like petals but were only minimally detected in the sepals. Yeast two-hybrid analysis indicated that CgDEF1 and CgGLO formed a heterodimer. CgAGL6-1/CgSEP2 and CgDEF1 formed higher-order protein complexes with the assistance of the CgGLO protein, and both CgAGL6-1 and CgSEP2 formed a heterodimer. CgDEF3/CgDEF4 could interact independently with CgGLO and CgAGL6-3, respectively, while CgDEF3 and CgDEF4 also formed heterodimers with the assistance of the CgGLO. Based on a comprehensive analysis relating these gene expression patterns to protein interaction profiles, the mechanism of sepal/petal/lip determination was studied in C. goeringii. Furthermore, a hypothesis explaining the sepal/petal/lip determination of C. goeringii is proposed. The lip-quartet (CgDEF3/CgDEF4/CgAGL6-3/CgGLO) promoted lip formation, whereas the sepal/petal-quartet (CgDEF1/CgAGL6-1/CgSEP2/CgGLO) promoted sepal/petal formation. These results enrich the current knowledge regarding the mechanism and pathways of perianth formation in orchids.
- Published
- 2017