Proline Accumulation and its Defensive Role Under Diverse Stress Condition in Plants: An Overview

Shahid

et al. 2020

IJERPH

Excessive use of fungicides in agriculture may result in substantial accumulation of active residues in soil, which affect crop health and yield. We investigated the response of Raphanus sativus (white radish) to fungicides in soil and potential beneficial interactions of radish plants with fungicide-tolerant plant growth-promoting rhizobacteria (PGPR). The PGPR were isolated from cabbage and mustard rhizospheres. Morphological and biochemical characteristics measured using standard methods, together with analysis of partial 16S rRNA gene sequences, revealed that fungicide-tolerant PGPR, isolates PS3 and AZ2, were closely related to Pseudomonas spp. These PGPR survived in the presence of high fungicide concentrations i.e., up to 2400 μg mL−1 carbendazim (CBZM) and 3200 μg mL−1 hexaconazole (HEXA). Bacterial isolates produced plant growth stimulants even under fungicide stress, though fungicides induced surface morphological distortion and alteration in membrane permeability of these bacteria, which was proved by a set of microscopic observations. Fungicides considerably affected the germination efficiency, growth, and physiological development of R. sativus, but these effects were relieved when inoculated with PGPR isolates. For instance, CBZM at 1500 mg kg−1 decreased whole dry biomass by 71%, whole plant length by 54%, total chlorophyll by 50%, protein content by 61%, and carotenoid production by 29%. After applying isolate AZ2 for white radish grown in CBZM (10 mg kg−1)-amended soil, it could improve plant growth and development with increased whole plant dry weight (10%), entire plant length (13%) and total chlorophyll content (18%). Similarly, isolate PS3 enhanced plant survival by relieving plant stress with declined biomarkers, i.e., proline (12%), malondialdehyde (3%), ascorbate peroxidase (6.5%), catalase (18%), and glutathione reductase (4%). Application of isolates AZ2 and PS3 could be effective for remediation of fungicide-contaminated soil and for improving the cultivation of radish plants while minimizing inputs of fungicides.

Section: Resultsmentioning

confidence: 99%

Fungicide-Tolerant Plant Growth-Promoting Rhizobacteria Mitigate Physiological Disruption of White Radish Caused by Fungicides Used in the Field Cultivation

Shahid

et al. 2020

IJERPH

“…Data on changes in proline content in plants at different oil concentrations in the soil are rather controversial and are determined by both the pollutant type and plant species. For example, it was previously shown that soil contamination with heavy metals, as a rule, leads to an increase in proline content in plants [ 49 , 50 ]. Additionally, a number of studies revealed a decrease in proline level in leaves of Plantago lanceolata [ 51 ] and Brassica juncea [ 52 ] exposed to heavy metal soil contamination.…”

Section: Discussionmentioning

confidence: 99%

Effect of Crude Oil on Growth, Oxidative Stress and Response of Antioxidative System of Two Rye (Secale cereale L.) Varieties

Skrypnik

Maslennikov

Novikova

et al. 2021

Plants

Rye (Secale cereale L.) is one of the most important cereal crops in Eastern and Northern Europe, showing better tolerance to environmental stress factors compared to wheat and triticale. Plant response to the crude oil-polluted soil depends on plant species, oil concentration, time of exposure, etc. The current study is aimed at investigating the growth, oxidative stress and the response of antioxidative system of two rye varieties (Krona and Valdai) cultivated on crude oil-contaminated soils at different concentrations (1.5, 3.0, 6.0, and 12.0%). Inhibition of rye growth was observed at crude oil concentrations of above 3% for above-ground plant parts and of above 1.5% for roots. A decrease in content of chlorophyll a and total chlorophylls in Krona variety was detected at 1.5% oil concentration in soil and in Valdai variety at 3% oil concentration. Compared with the control, the content of malondialdehyde was significantly increased in the Krona variety at 3% oil concentration and in Valdai variety at 6% oil concentration. The crude oil-induced oxidative stress was minimized in rye plants by the enhanced contents of low-molecular antioxidants (proline, non-protein thiols, ascorbic acid, phenolic compounds) and activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. The strongest positive correlation was detected between the content of malondialdehyde and contents of proline (r = 0.89–0.95, p ≤ 0.05) and phenolic compounds (r = 0.90–0.94, p ≤ 0.05) as well as superoxide dismutase activity (r = 0.81–0.90, p ≤ 0.05). Based on the results of a comprehensive analysis of growth and biochemical parameters and of the cluster analysis, Valdai variety proved to be more resistant to oil pollution. Due to this, Valdai variety is considered to be a promising rye variety for cultivation on moderately oil-polluted soils in order to decontaminate them. At the same time, it is necessary to conduct further studies aimed at investigating oil transformation processes in the soil-rye system, which would make it possible to determine the efficiency of using this cereal for soil remediation.

“…The maximum proline accumulation was recorded in ML stressed P. hysterophorus at 5 DAT. Higher proline levels suggest that compatible solutes contribute to the cellular osmoregulation and detoxification of reactive oxygen species 34 . There was also an increase in total soluble sugars under ML and HL stress at 3 DAT (Fig.…”

Section: Discussionmentioning

confidence: 99%

Parthenium hysterophorus steps up Ca-regulatory pathway in defence against highlight intensities

Ahmad

Baig

Amna

et al. 2020

Sci Rep

Parthenium hysterophorus exhibits tolerance to a great extent against abiotic stresses including high light intensities. in this study, P. hysterophorus was subjected to three different light intensities viz. control (CL, 250 µmol photons m −2 s −1), moderately high (ML, 500 µmol photons m −2 s −1) and high (HL, 1000 µmol photons m −2 s −1) for assessment of biochemical and physiological responses at 3 and 5 days after treatment (DAT). Proteomic responses were also observed at 5 DAT. Level of oxidative stress marker, abundance of H 2 o 2 and o 2 − was highest in leaves exposed to HL followed by ML treatment. Biomass accumulation, photosynthetic parameters, chloroplast and mitochondrial integrity were also affected by both ML and HL treatments. Differential protein expression data showed modulation of thirty-eight proteins in ML and HL intensities. P. hysterophorus exhibited good ability to survive in ML then HL treatment as demonstrated by enhancement of the antioxidant system and photosynthesis. furthermore, P. hysterophorus mobilized some key proteins related to calcium signaling, which in turn coordinate physiological homeostasis under stress. proline and total soluble sugar content were high under stress; however, results of simulated experiment of our study indicate such accumulation of osmolytes may inhibit photon-availability to chloroplast. these results clarify our understanding of the mechanisms underlying the light stress tolerance of P. hysterophorus. Light is one of the primary essential environmental factors that affect growth and development of plants. Any slight change in light intensity, duration and quality can influence the rate, pattern of growth and development which can significantly influence the productivity at mass scale 1,2. Sensitivity of a plant to high intensities of light may lead to failure in acclimation responses leading to cellular damage and ultimately to the death of plants 3. As the light energy absorption exceeds capacity of its usage in the chloroplasts, oxygenic photosynthesis electron transport is elevated, generating excessive reactive oxygen species (ROS) through photochemical energy conversion 4. ROS damages cellular components including photosynthetic reaction centers and peripherical light-harvesting structures. Such light-induced damages might decrease photosynthetic activity, known as photoinhibition which is still poorly understood 5,6. Also, how do plants respond to highlight intensities at a cellular level and what might be rescue mechanisms are still in need of full understanding. Under light stress, role of calcium could also be crucial in protection of plants and thylakoids 7,8 besides other protective mechanisms 1,9-11. Such mechanisms primarily, and effectively, include defence pathways those operate through modulation of proteome profiles 12-14. The efficiency of defense depends on degree of modulation, and qualitative composition of a proteome decides the degree of threshold to withstand abiotic stress. Compared to crop plants, weeds are generally much mor...