Vernalization shapes shoot architecture and ensures the maintenance of dormant buds in the perennial Arabis alpina

Abstract

Perennials have a complex shoot architecture with axillary meristems organized in zones of differential bud activity and fate. This includes zones of buds maintained dormant for multiple seasons and used as reservoirs for potential growth in case of damage. The shoot of Arabis alpina, a perennial relative of Arabidopsis thaliana, consists of a zone of dormant buds placed between subapical vegetative and basal flowering branches. This shoot architecture is shaped after exposure to prolonged cold, required for flowering.To understand how vernalization ensures the maintenance of dormant buds, we performed physiological and transcriptome studies, followed the spatiotemporal changes of auxin, and generated transgenic plants.Our results demonstrate that the complex shoot architecture in A. alpina is shaped by its flowering behavior, specifically the initiation of inflorescences during cold treatment and rapid flowering after subsequent exposure to growth-promoting conditions. Dormant buds are already formed before cold treatment. However, dormancy in these buds is enhanced during, and stably maintained after, vernalization by a BRC1-dependent mechanism. Post-vernalization, stable maintenance of dormant buds is correlated with increased auxin response, transport, and endogenous indole-3-acetic acid levels in the stem.Here, we provide a functional link between flowering and the maintenance of dormant buds in perennials.

Identification of Players Controlling Meristem Arrest Downstream of the FRUITFULL-APETALA2 Pathway

“…6). Taken together, our results suggest that the combination of high ABA response and low CK responsiveness could mediate meristem arrest at the end of the reproductive phase, inducing the dormant stage, as has been proposed for many species for the establishment and maintenance of bud dormancy (Corot et al, 2017;Tylewicz et al, 2018;Liu and Sherif, 2019;Vayssières et al, 2020).…”

Glycerolipid profile differences between perennial and annual stem zones in the perennial model plant Arabis alpina

“…(2018), and Vayssiѐres et al. (2020). (b, c) Lipid metabolism‐related GO terms enriched in (b) stage I_PZ (represented in black) versus stage III_PZ (represented in grey) and in (c) stage I_PZ (represented in black) versus stage IV_PZ (represented in grey).…”

“…A. alpina is polycarpic and produces new flowers during every new growth season at the distal ends of the main shoot and lateral branches. In proximal vegetative parts of the stems, buds develop either into non‐flowering branches, remain as perennating buds, or develop into flowering lateral branches that maintain vegetative growth (Lazaro et al., 2018; Vayssiѐres et al., 2020). This complex architecture of A. alpina is established during and after vernalization, a required cold season that induces flowering.…”

Beyond flowering time: diverse roles of an APETALA2‐like transcription factor in shoot architecture and perennial traits

“…New Phytologist (2021) 229: 444-459 Ó 2020 The Authors New Phytologist Ó 2020 New Phytologist Trust www.newphytologist.com species usually show a complex shoot architecture that can consist of dormant buds and axillary vegetative and/or flowering branches (Costes et al, 2014;Vayssi eres et al, 2020). This strategy of splitting resources towards vegetative and reproductive development affects yield (Bazzaz et al, 1987).…”

“…We demonstrated that AaTOE2 regulates the age‐dependent response to vernalisation and shoot architecture. We have previously shown that shoot architecture in A. alpina is organised in zones of differential bud activity and fate according to position on the plant named as V1 (zone of flowering axillary branches), V2 (zone of dormant buds) and V3 (zone of vegetative axillary branches) (Lázaro et al ., 2018; Vayssières et al ., 2020). Here we demonstrate that AaTOE2 contributes to shoot architecture by repressing flowering in axillary branches and determining the number of metamers in each zone.…”