Proline Accumulation in Leaves of Periploca sepium via Both Biosynthesis Up-Regulation and Transport during Recovery from Severe Drought

Abstract

Drought resistance and recovery ability are two important requisites for plant adaptation to drought environments. Proline (Pro) metabolism has been a major concern in plant drought tolerance. However, roles of Pro metabolism in plant recovery ability from severe drought stress are largely unexplored. Periploca sepium Bunge has gained increasing attention for its adaptation to dry environments. Here, we investigated Pro metabolism in different tissues of P. sepium seedlings in the course of drought stress and recovery. We found that leaf Pro metabolism response during post-drought recovery was dependant on drought severity. Pro biosynthesis was down-regulated during recovery from -0.4 MPa but increased continually and notably during recovery from -1.0 MPa. Significant correlation between Pro concentration and Δ1-pyrroline-5-carboxylate synthetase activity indicates that Glutamate pathway is the predominant synthesis route during both drought and re-watering periods. Ornithine δ-aminotransferase activity was up-regulated significantly only during recovery from −1.0 MPa, suggesting positive contribution of ornithine pathway to improving plant recovery capacity from severe drought. In addition to up-regulation of biosynthesis, Pro transport from stems and roots also contributed to high Pro accumulation in leaves and new buds during recovery from −1.0 MPa, as indicated by the combined analysis of Pro concentration and its biosynthesis in stems, roots and new buds. Except its known roles as energy, carbon and nitrogen sources for plant rapid recovery, significant positive correlation between Pro concentration and total antioxidant activity indicates that Pro accumulation can also promote plant damage repair ability by up-regulating antioxidant activity during recovery from severe drought stress.

Genotypic Variation in Growth and Physiological Response to Drought Stress and Re-Watering Reveals the Critical Role of Recovery in Drought Adaptation in Maize Seedlings

“…Data were analyzed by analysis of variance (ANOVA) using the least significant differences (LSD) post-hoc test, and a P < 0.05 was considered significant. Principle component analysis (PCA) was performed using the relative values of all physiological traits to comprehensively evaluate the differences in plant physiological responses among the lines, and the final total score was calculated to represent physiological responses according to the method of An et al ( 2013 ). Pearson correlations were calculated to determine the relationship among the drought-adaptive capabilities of the various lines and the relationship between their drought-adaptive capabilities and their physiological parameters or total scores of physiological responses.…”

Artemisia dominant species succession relating to the soil moisture decrease in abandoned land of the Loess Plateau (China): comparative study of drought-adaptive characteristics

“…Lipid peroxidation was determined by estimating the malondialdehyde (MDA) content in 1 g leaf fresh weight according to Hodges et al ( 1999 ). Leaves enzymes were extracted according to An et al ( 2013 ) with some modifications. Random 0.2 g fresh samples was homogenized with 4 mL 50 mM Na phosphate buffer solution (pH 7.8) including 1 % PVP and 0.1 mM EDTA, and centrifuged at 12,000× g for 20 min at 4 °C.…”

“…Catalase (CAT; EC 1.11.1.6) activity assay was measured according to Aebi ( 1984 ) which measures the decline of the extinction of H 2 O 2 (extinction coefficient 0.04 mM −1 cm −1 ) at the maximum absorption at 240 nm for 3 min. Peroxidase (POX; EC 1.11.1.7) activity was done according to the method of An et al ( 2013 ). The assay depends on the increase in absorbance at 470 nm, by the rate of formation of the oxidized guaiacol.…”

Response of Yellow Quality Protein Maize Inbred Lines to Drought stress at Seedling Stage

“…In drought-stressed chickpea, [21] a 10-foldincrease in Pro was recorded in comparison to non-stressed conditions. An et al [44] observed an increase in Pro of 6.15 times in drought-stressed Periploca sepium relative to non-stressed conditions. This shows that Pro released under drought-stressed conditions could be dependent on the plant species under evaluation, different genotypes within the plant species or the intensity of stress to which the plants were exposed.…”