Improving water use efficiency in grapevines: potential physiological targets for biotechnological improvement

Abstract

Improving water use efficiency (WUE) in grapevines is essential for vineyard sustainability under the increasing aridity induced by global climate change. WUE reflects the ratio between the carbon assimilated by photosynthesis and the water lost in transpiration. Maintaining stomata partially closed by regulated deficit irrigation or partial root drying represents an opportunity to increase WUE, although at the expense of decreased photosynthesis and, potentially, decreased yield. It would be even better to achieve increases in WUE by improving photosynthesis without increasing water loses. Although this is not yet possible, it could potentially be achieved by genetic engineering. This review presents current knowledge and relevant results that aim to improve WUE in grapevines by biotechnology and genetic engineering. The expected benefits of these manipulations on WUE of grapevines under water stress conditions are modelled. There are two main possible approaches to achieve this goal: (i) to improve CO2 diffusion to the sites of carboxylation without increasing stomatal conductance; and (ii) to improve the carboxylation efficiency of Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The first goal could be attained by increasing mesophyll conductance to CO2, which partly depends on aquaporins. The second approach could be achieved by replacing Rubisco from grapevine with Rubiscos from other C3 species with higher specificity for CO2. In summary, the physiological bases and future prospects for improving grape yield and WUE under drought are established. AbbreviationsRubisco ribulose-1,5-bisphosphate carboxylase/oxygenase; RuBP ribulose-1,5-bisphosphate; WUE water use efficiency; WUEC crop WUE; WUEleaf leaf-level WUE; WUEWP whole-plant WUE; WUEY yield WUE

Carbon balance, partitioning and photosynthetic acclimation in fruit-bearing grapevine (Vitis vinifera L. cv. Tempranillo) grown under simulated climate change (elevated CO2, elevated temperature and moderate drought) scenarios in temperature gradient greenhouses

“…Both stomatal (g S ) and mesophyll conductance reductions mediated by 2 drought decrease the Rubisco CO 2 availability, decreasing the CO 2 concentration in the 3 chloroplasts , and are the major cause for the decreased 4 photosynthesis observed in grapevines under water scarcity (Flexas et al, 2010). When 5 drought progresses, the photochemistry and biochemistry of the photosynthesis can be 6 affected, reducing the grapevine photosynthetic capacity 7 Morales et al, 2006).…”

Improving water use efficiency of vineyards in semi-arid regions. A review

“…More than 3 % variations under irrigation and drought conditions in δ 13 C has been reported; however, less cultivars have been studied using this parameter (Costa et al 2012;Flexas et al 2010;Gaudillère et al 2002;Tomás et al 2014a). Different types of whole plant measurements are used to estimate plant WUE depending on the specific study.…”

“…These important issues lead to the development of irrigation strategies by which grapevines receive a certain fraction of the water required that allows maintaining them under mild or severe water stress conditions with associated effects on yield reductions, maintenance, or increments in berry quality and improved WUE (Costa et al 2007;Flexas et al 2010).…”

“…During the last three decades, more frequent episodes of drought stress and their intensity required the incorporation of water by irrigation as a way to overcome such limitation and to secure more regular and predictable yields (Chaves et al , 2010Flexas et al 2010). However, two considerations need to be taken in account when irrigating grapevines: (i) water requirements are usually high in semi-arid areas thus potentially compromising water resources and sustainability of agricultural practices (FAO 2014) and (ii) yield increases are commonly associated to grape quality reductions, since grape quality usually decreases in response to an excess of vigor creating an unbalance between the reproductive and vegetative organs within plants (Bravdo et al 1985;Dokoozlian and Kliewer 1996;Esteban et al 2001;Matthews et al 1990;McCarthy 1997).…”

Reactions of grape varieties to climate changes in North East Slovenia

“…Northern regions may again be suitable for viticulture like during the medieval period, from 9 to 13 century AD (Kenny and Harrison 1992, Laget et al 2008, Flexas et al 2010. Growing season length and temperatures are critical aspects that have to be taken into consideration to maximize a style of wine and its quality (Jones et al 2005).…”