Identification of potential post‐ethylene events in the signaling cascade induced by stimuli of bud dormancy release in grapevine. (29th October 2020)

• Record Type: Journal Article
• Authors: Shi, Zhaowan; Halaly‐Basha, Tamar; Zheng, Chuanlin; Sharabi‐Schwager, Michal; Wang, Chen; Galbraith, David W.; Ophir, Ron; Pang, Xuequn; Or, Etti
• Is Part Of: Plant journal. Volume 104:Number 5(2020)
• Page Start: 1251
• Page End: 1268
• Publication Date: 2020-10-29
• Subjects: Vitis vinifera -- ethylene responding factor -- bud -- dormancy -- ethylene -- grapevine -- starvation -- autophagy -- macromolecule catabolism; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.14997
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: Ethylene signaling appears critical for grape bud dormancy release. We therefore focused on identification and characterization of potential downstream targets and events, assuming that they participate in the regulation of dormancy release. Because ethylene responding factors (ERF) are natural candidates for targets of ethylene signaling, we initially characterized the behavior of two VvERF‐VIIs, which we identified within a gene set induced by dormancy release stimuli. As expected, these VvERF‐VIIs are localized within the nucleus, and are stabilized upon decreases in oxygen availability within the dormant buds. Less expected, the proteins are also stabilized upon hydrogen cyanamide (HC) application under normoxic conditions, and their levels peak at deepest dormancy under vineyard conditions. We proceeded to catalog the response of all bud‐expressed ERFs, and identified additional ERFs that respond similarly to ethylene, HC, azide and hypoxia. We also identified a core set of genes that are similarly affected by treatment with ethylene and with various dormancy release stimuli. Interestingly, the functional annotations of this core set center around response to energy crisis and renewal of energy resources via autophagy‐mediated catabolism. Because ERF‐VIIs are stabilized under energy shortage and reshape cell metabolism to allow energy regeneration, we propose that: (i) the availability of VvERF‐VIIs is a consequence of an energy crisis within the bud; (ii) VvERF‐VIIs function as part of an energy‐regenerating mechanism, which activates anaerobic metabolism and autophagy‐mediated macromolecule catabolism; and (iii) activation of catabolism serves as the mandatory switch and the driving force for activation of the growth‐inhibited meristem during bud‐break. Significance Statement: The ability of various stresses, which are rationally expected to inhibit growth, to paradoxically activate growth of the dormant bud meristem, has been an enigma for decades. Collectively, our data propose: (i) that stress mediates energy regeneration under conditions of energy crisis, by induction of ethylene‐activated anaerobic metabolism and macromolecule catabolism; (ii) that activation of autophagy‐mediated catabolism serves as the mandatory switch and the driving force for activation of the growth‐inhibited meristem during bud‐break.