Responses of pomegranate cultivars to severe water stress and recovery: changes on antioxidant enzyme activities, gene expression patterns and water stress responsive metabolites

Abstract

The biochemical and molecular responses of five commercially well-known pomegranate cultivars to severe water stress were studied. The cultivars were subjected to 14-day water stress by withholding irrigation, followed by re-watering for 7 days. Results showed clear differences in metabolites contents and activities of antioxidant enzymes among various pomegranate cultivars during severe water stress and recovery. According to our results, increased accumulation of proline in pomegranate was not related to osmotic adjustment during severe water stress. Except for 'Ghojagh', leaves grown under severe water stress conditions showed symptoms of oxidative stress such as reduced chlorophyll concentration. The improved performance of 'Ghojagh' under drought stress may be associated with an efficient osmotic adjustment. The up-or down regulated expression of cytosolic glutathione reductase (cytosolic GR) and glutathione peroxidase were observed under drought conditions. Moreover, the suppressed expression of cytosolic GR was also noted. Comparatively, 'Rabab' exhibited higher antioxidant capacity and an efficient ROSscavenging mechanism under drought stress. Lower levels of membrane lipid peroxidation in 'Ghojagh' and 'Rabab' under drought stress and the marked reduction of malondialdehyde concentration after re-watering represents that these cultivars have a good tolerance to drought stress. As a first step towards the study of the biochemical and molecular responses of pomegranate plants to water stress, this research provides new information into the mechanisms of drought tolerance in the plants.

Desi and kabuli chickpea cultivars had differential behaviour towards salinity stress tolerance

“…MDA was found to be negatively correlated with proline in the present investigation indicating that osmolyte helps to decrease the membrane destruction [24]. Lower MDA concentration is indicator of tolerance ability of pomegranate cultivars [30].…”

Morphological and biochemical responses of Balanites aegyptiaca to drought stress and recovery are provenance‐dependent

“…With the exception of the sensitive Cairo provenance, B. aegyptiaca provenances showed a reduction in stomatal conductance as avoidance mechanism under moderate and severe drought stress compared to the control. The parallel reduction in plant water content and stomatal conductance by severe drought was reported in several plant species such as pomegranate (Pourghayoumi et al., ), Allocasuarina luehmannii (Aiton) L. A. S. Johnson (Posch & Bennett, ) and olive trees (Boussadia et al., ). Stomata closure also negatively affects CO 2 assimilation and reduces gas exchange to preserve the water level.…”

“…The increase in MDA after water stress was also reported in olive trees (Petridis et al., ). The drought‐tolerant pomegranate (“Ghojagh” and “Rabab” cultivars) produced less MDA compared to the susceptible “M‐Yazdi” cultivar which produced more MDA content under severe stress (Pourghayoumi et al., ). The increase in MDA under severe stress could also be related to membrane damage in the Saharian plant Oudneya africana R. Br.…”

“…Induced antioxidant defence and osmotic adjustment through accumulation of compatible solutes in living cells are protective mechanism to keep water balance, save cellular structure and retard dehydration under drought stress condition (Anjum et al, 2017;Chaves, Maroco, & Pereira, 2003;Taiz & Zeiger, 2006). Plants can develop defence mechanisms against free radical-induced oxidative stress through a number of enzymatic and non-enzymatic antioxidant defences (Pourghayoumi, Rahemi, Bakhshi, Aalami, & Kamgar-Haghighi, 2017). Production of antioxidants such as tocopherols and ROS scavenging enzymes, such as catalase, peroxidase, superoxide dismutase and polyphenol oxidase enzymes, allows ROS scavenging and the protection of plant cells from oxidative damage and negative effects of drought stress (Sofo et al, 2004).…”

“…Increased antioxidant activities under severe stress were observed in plants such as oak (Quercus robur L.) (Schwanz & Polle, 2001), olive tree (O. europaea) and strawberry tree (Arbutus unedo L.) (Sofo et al, 2004). The intensity of drought tolerance was different among various pomegranate cultivars (Pourghayoumi et al, 2017). The regulation of antioxidant content and activities of ROS scavenging enzymes in the leaf growth zone is correlated with drought tolerance in maize lines from the European and African continent (Avramova et al, 2017).…”