A single dominant GLOBOSA allele accounts for repeated origins of hose-in-hose flowers in Sinningia (Gesneriaceae)

Xia Yang; Qi Liu; Miao-Miao Wang; Xiao-Ya Wang; Meng-Qi Han; Fang-Pu Liu; Tian-Feng Lü; Jing Liu; Yin-Zheng Wang

doi:10.1093/plcell/koae283

A single dominant GLOBOSA allele accounts for repeated origins of hose-in-hose flowers in Sinningia (Gesneriaceae)

Plant Cell. 2024 Oct 18:koae283. doi: 10.1093/plcell/koae283. Online ahead of print.

Authors

Xia Yang^{1

2}, Qi Liu^{1

2

3}, Miao-Miao Wang⁴, Xiao-Ya Wang^{1

2

3}, Meng-Qi Han^{1

2

3}, Fang-Pu Liu^{1

2

3}, Tian-Feng Lü^{1

2}, Jing Liu^{1

2}, Yin-Zheng Wang^{1

2

3}

Affiliations

¹ Key Laboratory of Plant Diversity and Specialty Crops, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China.
² China National Botanical Garden (South Garden), Beijing 100093, China.
³ College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100049, China.
⁴ China National Botanical Garden (North Garden), Beijing 100093, China.

PMID: 39422240
DOI: 10.1093/plcell/koae283

Abstract

Plants bearing double flowers have long been cultivated as ornamental plants. Hose-in-hose flowers, bearing 2-whorled corolla tubes in whorls 1 and 2, are uncommon but recur in Sinningia (Gesnerioideae, Gesneriaceae). In this study, we selected 15 hose-in-hose cultivars as materials to explore the underlying molecular and genetic mechanisms of this floral architecture. We found that they originated from different hybridization events within the Dircaea clade. Three B-class MADS-box genes were globally expressed in all floral whorls, but only GLOBOSA1 (GLO1) has accumulated a dominant mutation, i.e., the insertion of a hAT-like miniature inverted-repeat transposable element (MITE) into its promoter, that co-segregated with the hose-in-hose phenotype. In addition, all 15 hose-in-hose cultivars contained the same dominant GLO1 allele. Transient gene expression assays confirmed the role of this MITE insertion in up-regulating the promoter activity of GLO1 by providing several cis-regulatory elements. Genetic transformation in heterologous Chirita pumila (Didymocarpoideae, Gesneriaceae) verified that this dominant GLO1 allele is sufficient to confer the hose-in-hose phenotype. We further demonstrated that both the GLO1 allele and the hAT-like MITE descended from wild S. cardinalis with single flowers. This study highlights the significance of wide hybridization in frequent gains of the dominant GLO1 allele and thereafter repeated occurrence of hose-in-hose flowers in Sinningia.

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