Transcriptomic Analysis Suggests Auxin Regulation in Dorsal–Ventral Petal Asymmetry of Wild Progenitor Sinningia speciosa
Journal
International Journal of Molecular Sciences
Journal Volume
23
Journal Issue
4
Pages
Article number 2073
Date Issued
2022-02-01
Author(s)
Pan, Zhao Jun
Nien, Ya Chi
Shih, Yu An
Chen, Tsun Ying
Lin, Wen Dar
Kuo, Wen Hsi
Hsu, Hao Chun
Tu, Shih Long
Abstract
The establishment of dorsal–ventral (DV) petal asymmetry is accompanied by differential growth of DV petal size, shape, and color differences, which enhance ornamental values. Genes involved in flower symmetry in Sinningia speciosa have been identified as CYCLOIDEA (SsCYC), but which gene regulatory network (GRN) is associated with SsCYC to establish DV petal asymmetry is still unknown. To uncover the GRN of DV petal asymmetry, we identified 630 DV differentially expressed genes (DV-DEGs) from the RNA-Seq of dorsal and ventral petals in the wild progenitor, S. speciosa ‘ES’. Validated by qRT-PCR, genes in the auxin signaling transduction pathway, SsCYC, and a major regulator of anthocyanin biosynthesis were upregulated in dorsal petals. These genes correlated with a higher endogenous auxin level in dorsal petals, with longer tube length growth through cell expansion and a purple dorsal color. Over-expression of SsCYC in Nicotiana reduced petal size by regulating cell growth, suggesting that SsCYC also controls cell expansion. This suggests that auxin and SsCYC both regulate DV petal asymmetry. Transiently over-expressed SsCYC, however, could not activate most major auxin signaling genes, suggesting that SsCYC may not trigger auxin regulation. Whether auxin can activate SsCYC or whether they act independently to regulate DV petal asymmetry remains to be explored in the future.
Subjects
Auxin | Cell growth | Floral symmetry | Petal pigmentation | Petal size
Publisher
MDPI
Type
journal article