RNA-seq analysis reveals different transcriptomic responses to GA3 in early- and mid-season varieties before ripening initiation in sweet cherry (Prunus avium L.) fruits

Abstract

Gibberellin (GA) negatively affects color evolution and other ripening-related processes in non-climacteric fruits. The bioactive GA, gibberellic acid (GA3), is commonly applied at the light green-to-straw yellow transition to increase firmness and delay ripening in sweet cherry (Prunus avium L.), though causing different effects depending on the variety. Recently, we reported that GA3 delayed the IAD parameter (a ripening index) in a mid-season variety, whereas GA3 did not delay IAD but reduced it at ripeness in an early-season variety. To further explore this contrasting behavior between varieties, we analyzed the transcriptomic responses to GA3 applied on two sweet cherry varieties with different maturity time phenotypes. At harvest, GA3 produced fruits with less color in both varieties. Similar to our previous report, GA3 delayed fruit color initiation and IAD only in the mid-season variety, and reduced IAD at harvest only in the early-season variety. RNA-seq analysis of control- and GA3-treated fruits of both varieties revealed that ripening related categories were overrepresented in the early-season variety, including 'photosynthesis' and 'auxin response.' GA3 also changed the expression of carotenoid and abscisic acid (ABA) biosynthetic genes in this variety. In contrast, overrepresented categories in the mid-season variety were related mainly to metabolic processes. In this variety, some PP2Cs putative genes were positively regulated by GA3, which are negative regulators of ABA responses. This was accompanied with downregulation of MYB44-like genes, putative repressors of PP2Cs expression. These results show that GA3 differentially modulates the transcriptome at the onset of ripening in a variety-dependent manner and suggest that GA3 impairs ripening through the modification of ripening associated gene expression only in the early-season variety; whereas in the mid-season variety, possibly a control of the ripening timing occurs through the PP2C gene expression regulation. This work contributes to the understanding of the role of GA in non-climacteric fruit ripening.

Transcriptomics reveal useful resources for examining fruit development and variation in fruit size in Coccinia grandis

“…Cucurbitaceae is the second largest family bearing diverse groups of plant with broad range of fruit characteristic (Shaina and Suhara Beevy, 2012;Ma et al, 2020). Studies related to fruit development and variations in fruit sizes are also reported in other plants like Arabidopsis, tomato, pear, pumpkin, cucumber, bottle gourd, apple, Apricot, sweet cherry among many others (Jiang et al, 2015;Xanthopoulou et al, 2017;Di Marzo et al, 2020;Yuste-Lisbona et al, 2020;Zhang et al, 2020;Kuhn et al, 2021;Liu et al, 2023;Wang et al, 2022;Jahed and Hirst, 2023). RNA-Seq analyses have become the most popular method to identify the key genes regulating fruit morphology in several cucurbit vegetables (Zhang et al, 2016;Ma et al, 2020;Chen et al, 2021).…”

Transcriptomic and DNA methylation modifications during fruit ripening and in response to ABA treatment in sweet cherry

“…A coexpression analysis conducted at the onset of ripening (veraison) of two contrasting grapevine varieties during harvest revealed significant transcriptomic rearrangements that define the reprogramming of berry development (Fasoli et al, 2018). In the same line, a recent work of our group, conducted in two contrasting sweet cherry varieties with differences in the initiation of ripening, showed that they present significant differences at the transcriptomic level, including several genes involved in hormone biosynthesis and signaling, as well as transcriptional regulation (Kuhn et al, 2021b).…”

“…Our results suggest a possible role of ABA in ripening modulation by controlling the expression of the auxin response pathway. This pathway is also influenced by gibberellin in sweet cherry (Kuhn et al, 2021b), so a possibility arises where ABA and gibberellin control ripening initiation by regulating auxin response genes.…”

“…2A and 2C). Other plant hormones, such as IAA and gibberellins, are antagonistic hormones of ripening (Böttcher et al, 2010;Teribia et al, 2016;Kuhn et al, 2020;Kuhn et al, 2021b). ABA reduces the IAA content when applied before color initiation in sweet cherry (Wang et al, 2015).…”

High temperature inhibited the accumulation of anthocyanin by promoting ABA catabolism in sweet cherry fruits

“…Previous studies showed that GA mainly exerted a negative role in the ripening and coloring process of sweet cherry. GA 3 application delays ABA accumulation, fruit size increase and ripening, reduces anthocyanin levels and produces fruits with less color (Kondo and Danjo, 2001;Usenik et al, 2005;Kuhn et al, 2021). GA 4 is also significantly and inversely correlated with the ripening parameters of sweet cherry (Teribia et al, 2016).…”