Moderate Drought Stress Induces Increased Foliar Dimethylsulphoniopropionate (DMSP) Concentration and Isoprene Emission in Two Contrasting Ecotypes of Arundo donax

Abstract

The function of dimethylsulphoniopropionate (DMSP) in plants is unclear. It has been proposed as an antioxidant, osmolyte and overflow for excess energy under stress conditions. The formation of DMSP is part of the methionine (MET) pathway that is involved in plant stress responses. We used a new analytical approach to accurately quantify the changes in DMSP concentration that occurred in two ecotypes of the biomass crop Arundo donax subject to moderate drought stress under field conditions. The ecotypes of A. donax were from a hot semi-arid habitat in Morocco and a warm-humid environment in Central Italy. The Moroccan ecotype showed more pronounced reductions in photosynthesis, stomatal conductance and photochemical electron transport than the Italian ecotype. An increase in isoprene emission occurred in both ecotypes alongside enhanced foliar concentrations of DMSP, indicative of a protective function of these two metabolites in the amelioration of the deleterious effects of excess energy and oxidative stress. This is consistent with the modification of carbon within the methyl-erythritol and MET pathways responsible for increased synthesis of isoprene and DMSP under moderate drought. The results of this study indicate that DMSP is an important adaptive component of the stress response regulated via the MET pathway in A. donax. DMSP is likely a multifunctional molecule playing a number of roles in the response of A. donax to reduced water availability.

Giant reed genotypes from temperate and arid environments show different response mechanisms to drought

“…) (Morfopoulos et al ) that, in turn, may confer oxidative and heat stress protection (Peñuelas et al , Loreto and Schnitzler ). These results are in line with those found by Ahrar et al () and Haworth et al (, ), which showed that isoprene emission from different genotypes of giant reed was stimulated by water stress.…”

“…As expected, the decrease in g s was accompanied by a decrease in P n (Fig. 1) in a typical hyperbolic relationship fashion confirming a strong diffusive limitation to P n under DR conditions (Nackley et al 2014, Haworth et al 2017a, 2017b. Consistently with biomass production, P n and g s decreased, respectively, by 30 and 59% with DR.…”

“…3) (Morfopoulos et al 2013) that, in turn, may confer oxidative and heat stress protection (Peñuelas et al 2005, Loreto andSchnitzler 2010). These results are in line with those found by Ahrar et al (2017) and Haworth et al (2017aHaworth et al ( , 2017c, which showed that isoprene emission from different genotypes of giant reed was stimulated by water stress. On the other hand, stem xylem vessels area and hydraulic conductance seem to be major constrains to maintain a higher water status in giant reed.…”

A Comparison of the Variable J and Carbon-Isotopic Composition of Sugars Methods to Assess Mesophyll Conductance from the Leaf to the Canopy Scale in Drought-Stressed Cherry

“…However, the δ 13 C values of leaf petiole sugars were higher than sugars from the leaf or branch sap (Table 1) in both well-watered control and drought-stressed plants, indicating a higher proportion of the heavier 13 C-isotope. The higher δ 13 C of sugars from the leaf petiole sap may reflect the impact of increased discrimination against sugars composed of the heavier isotope [51] during respiration or at other branch points of the metabolic pathways within the leaf, the methylerythritol pathway [52]. Discrimination in favour of sugars composed of the lighter 12 C-isotope will progressively enrich the remaining pool of photosynthetic sugars destined for export from the leaves to the other parts of the plant.…”

Impact of high phosphorous and sodium on productivity and stress tolerance of Arundo donax plants

“…A. donax leaves constitutively produce a large amount of isoprene (Velikova et al , 2016), which is known to be involved in mechanisms of protection against abiotic (Vickers et al , 2009) and biotic stresses (Loivamäki et al , 2008). However, there is no clear pattern in isoprene emission in response to abiotic stress in reeds, as isoprene emission increased in A. donax following drought (Haworth et al , 2017a), decreased in Phragmites australis (the common reed, and a close relative of Arundo) plants exposed to high P concentrations (Fares et al , 2006), and was unaltered in salt-stressed A. donax (Pollastri et al , 2018).…”