An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

Abstract

ORCID IDs: 0000-0002-6288-7917 (Y.J.); 0000-0002-5972-7963 (C.-Z.J.); 0000-0002-3866-0894 (C.M.); 0000-0002-9285-2539 (J.G.).In many plant species, including rose (Rosa hybrida), flower senescence is promoted by the gaseous hormone ethylene and inhibited by the cytokinin (CTK) class of hormones. However, the molecular mechanisms underlying these antagonistic effects are not well understood. In this study, we characterized the association between a pathogenesis-related PR-10 family gene from rose (RhPR10.1) and the hormonal regulation of flower senescence. Quantitative reverse transcription PCR analysis showed that RhPR10.1 was expressed at high levels during senescence in different floral organs, including petal, sepal, receptacle, stamen, and pistil, and that expression was induced by ethylene treatment. Silencing of RhPR10.1 expression in rose plants by virusinduced gene silencing accelerated flower senescence, which was accompanied by a higher ion leakage rate in the petals, as well as increased expression of the senescence marker gene RhSAG12. CTK content and the expression of three CTK signaling pathway genes were reduced in RhPR10.1-silenced plants, and the accelerated rate of petal senescence that was apparent in the RhPR10.1-silenced plants was restored to normal levels by CTK treatment. Finally, RhHB6, a homeodomain-Leu zipper I transcription factor, was observed to bind to the RhPR10.1 promoter, and silencing of its expression also promoted flower senescence. Our results reveal an ethylene-induced RhHB6-RhPR10.1 regulatory module that functions as a brake of ethylenepromoted senescence through increasing the CTK content.

Rosa hybrida RhERF1 and RhERF4 mediate ethylene‐ and auxin‐regulated petal abscission by influencing pectin degradation

“…Petal AZ samples were collected by excising the base of the petals (<2 mm in length) and the area of the receptacles connected to the petals (<2 mm in length) (Gao et al ., ). The petal samples were collected from the middle whorl of the flowers (Wu et al ., ). The receptacle samples were collected from the receptacle adjacent to the petal AZ.…”

“…Total RNA was extracted from rose floral organs using the hot borate method as previously described (Wu et al ., ). Briefly, plant materials were ground in liquid nitrogen and then homogenized in preheated extraction buffer (200 m m sodium tetraborate decahydrate, 30 m m EGTA, 1% deoxycholic acid sodium salt, 10 m m dithiothreitol, 2% polyvinylpyrrolidone 40, 1% Nonidet P‐40).…”

Proteome and Ubiquitome Changes during Rose Petal Senescence

“…In morning glory (Ipomoea nil), the silencing of EPHEMERAL1, a NAC transcription factor, suppresses petal senescence [38]. In rose, two HD-Zip proteins, RhHB1 and RhHB6, regulate petal senescence positively and negatively, respectively [39,40]. In petunia, PhHD-Zip regulates petal senescence by promoting ABA biosynthesis [41].…”

A CsTu‐TS1 regulatory module promotes fruit tubercule formation in cucumber

“…Fresh fruit tubercules (50 mg) at 0 DBF were frozen in liquid nitrogen. As previously described, the extraction and quantification of endogenous auxins and cytokinin were performed using the HPLC electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) (Wu et al, 2016).…”