Two Rumex Species from Contrasting Hydrological Niches Regulate Flooding Tolerance through Distinct Mechanisms

Abstract

ORCID ID: 0000-0002-6940-0657 (R.S.).Global climate change has increased flooding events, which affect both natural vegetation dynamics and crop productivity. The flooded environment is lethal for most plant species because it restricts gas exchange and induces an energy and carbon crisis. Flooding survival strategies have been studied in Oryza sativa, a cultivated monocot. However, our understanding of plant adaptation to natural flood-prone environments remains scant, even though wild plants represent a valuable resource of tolerance mechanisms that could be used to generate stress-tolerant crops. Here we identify mechanisms that mediate the distinct flooding survival strategies of two related wild dicot species: Rumex palustris and Rumex acetosa. Whole transcriptome sequencing and metabolite profiling reveal flooding-induced metabolic reprogramming specific to R. acetosa. By contrast, R. palustris uses the early flooding signal ethylene to increase survival by regulating shade avoidance and photomorphogenesis genes to outgrow submergence and by priming submerged plants for future low oxygen stress. These results provide molecular resolution of flooding survival strategies of two species occupying distinct hydrological niches. Learning how these contrasting flood adaptive strategies evolved in nature will be instrumental for the development of stress-tolerant crop varieties that deliver enhanced yields in a changing climate.

A Co-Opted Hormonal Cascade Activates Dormant Adventitious Root Primordia upon Flooding in Solanum dulcamara

“…3C). A similar negative relation between ethylene and ABA accumulation has been described earlier in shoot growth responses to flooding in R. palustris and rice (Saika et al, 2007;van Veen et al, 2013) and in germinating seeds and seedlings in Order of lines is according to significance of difference with the wild type. Data are means 6 SE (n = 2-4).…”

Ethylene-Mediated Acclimations to Flooding Stress

“…Internal oxygen levels in the shoot are determined by light availability, presence of leaf gas films, and leaf traits that facilitate underwater photosynthesis and inward diffusion of oxygen, even under restricted conditions of the aquatic environment (Mommer et al, 2004;Pedersen et al, 2009). In fact, in planta oxygen measurements show that, in the presence of sufficient illumination, internal oxygen content can stay at normoxic values in submerged shoots van Veen et al, 2013).…”

QTL for chlorophyll fluorescence of barley plants grown at low oxygen concentration in hydroponics to simulate waterlogging

“…Tolerant plants seem to be able to maintain or conserve energy, but also escape mechanisms are common (Hattori et al 2009;van Veen et al 2013). Chlorophyll fluorescence is widely accepted as an indicator of the activity of PSII, which is involved in electron transport in plant photosynthesis and is particularly sensitive to stresses (Fracheboud et al 2004;Guo et al 2008;Gu et al 2012).…”