Aquaporin expression in response to different water stress intensities and recovery in Richter-110 (Vitis sp.): relationship with ecophysiological status

Abstract

Aquaporins seem essential for the regulation of plant water status and expenses. Richter-110 is a Vitis hybrid (Vitis berlandieri x rupestris) reputed to be strongly drought-tolerant. Three irrigation treatments were established in Richter-110 plants growing outdoors defined by the resulting maximum stomatal conductance (g (s)), and ensuring water stress situations not severe enough as to stop photosynthesis and growth: well-watered plants (g (s) about 250 mmol H(2)O m(-2) s(-1)), moderate water stress (g (s) about 150 mmol H(2)O m(-2) s(-1)) and severe water stress (g (s) about 50 mmol H(2)O m(-2) s(-1)). Plants under water stress were kept at constant water availability for 7 days to check for possible acclimation. Finally, plants were re-watered, and allowed to recover, for 3 days. Stomatal conductance, leaf water potential, xylem abscisic acid (ABA) content and root and stem hydraulic conductivity were determined. The relative amounts of expression of mRNA encoding seven putative aquaporins were determined in roots and leaves by RT-PCR. The decrease in stomatal conductance with moderate and severe water stress was associated with increasing ABA contents, but not with the leaf water potential and hydraulic conductivities, which remained unchanged during the entire experiment. Aquaporin gene expression varied depending on which aquaporin, water stress level and the plant organ. We suggest that aquaporin expression was responsive to water stress as part of the homeostasis, which resulted in constant leaf water potential and hydraulic conductivity.

An integrated approach shows different use of water resources from Mediterranean maquis species in a coastal dune ecosystem

“…Changes in permeability may also compensate for reduced water availability, allowing to some extent to keep l constant independently from SWC. This mechanism has been reported for a Vitis hybrid (Galmés et al, 2007) and allowed for an adequate water supply even at low SWC.…”

The Role of Plasma Membrane Intrinsic Protein Aquaporins in Water Transport through Roots: Diurnal and Drought Stress Responses Reveal Different Strategies between Isohydric and Anisohydric Cultivars of Grapevine

“…We expected changes in aquaporin expression to match changes in whole root and cell hydraulic conductivity in a genotype-3 environment-dependent manner, broadly reflecting the different strategies to drought stress in the two cultivars. Grenache has been shown to be nearly isohydric, exerting a tight regulation of stomatal aperture that may contribute to drought tolerance (Schultz, 2003;Soar et al, 2006), and is considered to be more drought tolerant than Chardonnay (Alsina et al, 2007). Gibberd et al (2001) presented data for transpiration efficiency and transpiration per unit leaf area for a number of cultivars, including Grenache and Chardonnay, grown in the same well-watered glasshouse conditions.…”

The Grapevine Root-Specific Aquaporin VvPIP2;4N Controls Root Hydraulic Conductance and Leaf Gas Exchange under Well-Watered Conditions But Not under Water Stress

“…species are well adapted to drought conditions and are thus expected to have developed efficient mechanisms to transfer water to their growing aerial organs and to limit negative effects of drought. Patterns of aquaporin expression and function are suspected to contribute significantly to this adaptation (Galmés et al, 2007;Vandeleur et al, 2009). Cultivated grapevine (Vitis vinifera) is traditionally a nonirrigated crop, and both yield and berry quality strongly depend on the vine adaptability to drought (for review of the molecular and physiological aspects of grapevine drought responses, see Lovisolo et al, 2010).…”