Differential and reciprocal regulation of ethylene pathway genes regulates petal abscission in fragrant and non-fragrant roses

Petal abscission in fragrant roses is associated with large scale differential regulation of the abscission zone transcriptome

“…This is a much higher number than a previous study where AZ samples were collected at different stages of bud development of R. chinensis 30 in absence of ethylene treatment. Our study confirms that ethylene accelerates abscission in fragrant roses 11 , 25 , 61 by causing a major change in gene expression in the AZ. The expression of reference genes, identified previously for rose 64 , 65 , did not change in AZs even upon ethylene treatment, indicating their utility as reference for abscission studies (Fig.…”

“…3 ) was not surprising. Our own detailed analysis of the ethylene pathway 25 confirmed the up-regulation of ethylene biosynthesis and signalling in R. bourboniana during abscission but its suppression in R. hybrida . Unlike ethylene, endogenous auxin prevents abscission by reducing AZ sensitivity to ethylene 29 , 70 .…”

“…The reciprocal regulation of the HK/phosphatase family indicates that targets of these proteins may be specific abscission determinants. Indeed, three of the HKs were identified as ETR3, ETR7 and ETR8 that are up-regulated by ethylene 25 while one was identified as a homologue of AHK4 , the Arabidopsis cytokinin receptor. Surprisingly, this group also contained the tomato orthologues of PHYA and PHYB , both of which were up-regulated, while the orthologue of PHYE was down-regulated.…”

“…In contrast, the non-fragrant R. hybrida is less sensitive to ethylene and has greater vase life of several days. These differences are partly associated with differences in sensitivities of the ethylene pathway 25 which in turn affect expression of cell wall modifying genes and programmed cell death-like processes 11 , 59 – 63 . Nevertheless, the molecular determinants that are responsible for regulation of petal abscission in fragrant and non-fragrant roses remain unclear and need to be identified to increase flower life in roses.…”

LcEIL2/3 are involved in fruitlet abscission via activating genes related to ethylene biosynthesis and cell wall remodeling in litchi

“…Additionally, cytoplasmic EIN2 can also suppress the translation of EIN3 BINDING F‐box 1 (EBF1) and EBF2 (Merchante et al ., 2015; Li et al ., 2015c). To date, the expression of genes involved in ET biosynthesis and signaling has been shown to be changed during the ET‐induced organ abscission in many species (Rasori et al ., 2002; Dal Cin et al ., 2005; Agusti et al ., 2008; Mishra et al ., 2008; Botton et al ., 2011; Sundaresan et al ., 2015a,b; Li et al ., 2015a; Gao et al ., 2019; Meng et al ., 2019; Singh et al ., 2019). Furthermore, regulatory genes involved in ET signaling have been revealed to have a positive effect on abscission.…”