A petunia transcription factor, PhOBF1, regulates flower senescence by modulating gibberellin biosynthesis

Abstract

Flower senescence is commonly enhanced by the endogenous hormone ethylene and suppressed by the gibberellins (GAs) in plants. However, the detailed mechanisms for the antagonism of these hormones during flower senescence remain elusive. In this study, we characterized one up-regulated gene PhOBF1, belonging to the basic leucine zipper transcription factor family, in senescing petals of petunia (Petunia hybrida). Exogenous treatments with ethylene and GA3 provoked a dramatic increase in PhOBF1 transcripts. Compared with wild-type plants, PhOBF1-RNAi transgenic petunia plants exhibited shortened flower longevity, while overexpression of PhOBF1 resulted in delayed flower senescence. Transcript abundances of two senescence-related genes PhSAG12 and PhSAG29 were higher in PhOBF1-silenced plants but lower in PhOBF1-overexpressing plants. Silencing and overexpression of PhOBF1 affected expression levels of a few genes involved in the GA biosynthesis and signaling pathways, as well as accumulation levels of bioactive GAs GA1 and GA3. Application of GA3 restored the accelerated petal senescence to normal levels in PhOBF1-RNAi transgenic petunia lines, and reduced ethylene release and transcription of three ethylene biosynthetic genes PhACO1, PhACS1, and PhACS2. Moreover, PhOBF1 was observed to specifically bind to the PhGA20ox3 promoter containing a G-box motif. Transient silencing of PhGA20ox3 in petunia plants through tobacco rattle virus-based virus-induced gene silencing method led to accelerated corolla senescence. Our results suggest that PhOBF1 functions as a negative regulator of ethylene-mediated flower senescence by modulating the GA production.

A tree peony RING-H2 finger protein, PsATL33, plays an essential role in cold-induced bud dormancy release by regulating gibberellin content

“…Petunia seeds ( Petunia hybrida ‘Mitchell Diploid’), obtained from Goldsmith Seeds (Gilroy, CA, USA), were sown in a tray containing the same soil mixture. The leaflets were harvested as the explants for Agrobacterium -mediated stable transformation ( Ji et al., 2023 ). Wild-type (WT) and transgenic petunia plants were grown in the plastic pots (11-cm height, 11-cm top diameter, and 9-cm bottom diameter) and irrigated as mentioned above.…”

Investigation of Volatile Components and Assessment of Antioxidant Potential in Seven Lamiaceae Plant Hydrosols

“…PCA, HCA, and OPLS-DA models were generated utilizing SIMCA 14.1. Correlation analysis was generated utilizing the OmicStudio tool [ 46 , 50 ].…”

Evolutionary and Integrative Analysis of the Gibberellin 20-oxidase, 3-oxidase, and 2-oxidase Gene Family in Paeonia ostii: Insight into Their Roles in Flower Senescence

“…GAs are also pivotal in the regulation of key physiological functions, such as seed germination, shoot elongation, leaf development, and fruit and flower senescence (Liao et al, 2019;Wang et al, 2016) [12,13]. Prior research has demonstrated that GA application can extend the lifespan of flowers in species like rose, iris, tobacco, allamanda, freesia, and peony (Ji et al, 2022;Ji et al, 2023a) [14,15]. GAs exhibit antagonism towards ethylene and abscisic acid (ABA) in senescing flowers, with a decline in bioactive GAs accelerating ethylene-and ABA-induced petal senescence in herbaceous peony and rose (Ji et al, 2023b;Lu et al, 2014) [16,17].…”

“…GAs exhibit antagonism towards ethylene and abscisic acid (ABA) in senescing flowers, with a decline in bioactive GAs accelerating ethylene-and ABA-induced petal senescence in herbaceous peony and rose (Ji et al, 2023b;Lu et al, 2014) [16,17]. A recent study indicated that the PhOBF1 (ocselement-binding protein 1) gene in petunia acts as a suppressor of ethylene-induced flower senescence by modulating GA biosynthesis (Ji et al, 2023a) [15]. Consequently, administering gibberellin application delays, whereas ABA or ethylene hastens, the senescence of peony petals.…”