Dataset Information

Sphingobacterium sp. BHU-AV3 Induces Salt Tolerance in Tomato by Enhancing Antioxidant Activities and Energy Metabolism.

ABSTRACT: Salt tolerant bacteria can be helpful in improving a plant's tolerance to salinity. Although plant-bacteria interactions in response to salt stress have been characterized, the precise molecular mechanisms by which bacterial inoculation alleviates salt stress in plants are still poorly explored. In the present study, we aimed to determine the role of a salt-tolerant plant growth-promoting rhizobacteria (PGPR) Sphingobacterium BHU-AV3 for improving salt tolerance in tomato through investigating the physiological responses of tomato roots and leaves under salinity stress. Tomato plants inoculated with BHU-AV3 and challenged with 200 mM NaCl exhibited less senescence, positively correlated with the maintenance of ion balance, lowered reactive oxygen species (ROS), and increased proline content compared to the non-inoculated plants. BHU-AV3-inoculated plant leaves were less affected by oxidative stress, as evident from a reduction in superoxide contents, cell death, and lipid peroxidation. The reduction in ROS level was associated with the increased antioxidant enzyme activities along with multiple-isoform expression [peroxidase (POD), polyphenol oxidase (PPO), and superoxide dismutase (SOD)] in plant roots. Additionally, BHU-AV3 inoculation induced the expression of proteins involved in (i) energy production [ATP synthase], (ii) carbohydrate metabolism (enolase), (iii) thiamine biosynthesis protein, (iv) translation protein (elongation factor 1 alpha), and the antioxidant defense system (catalase) in tomato roots. These findings have provided insight into the molecular mechanisms of bacteria-mediated alleviation of salt stress in plants. From the study, we can conclude that BHU-AV3 inoculation effectively induces antioxidant systems and energy metabolism in tomato roots, which leads to whole plant protection during salt stress through induced systemic tolerance.

SUBMITTER: Vaishnav A

PROVIDER: S-EPMC7145953 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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<i>Sphingobacterium</i> sp. BHU-AV3 Induces Salt Tolerance in Tomato by Enhancing Antioxidant Activities and Energy Metabolism.

Vaishnav Anukool A Singh Jyoti J Singh Prachi P Rajput Rahul Singh RS Singh Harikesh Bahadur HB Sarma Birinchi K BK

Frontiers in microbiology 20200403

Salt tolerant bacteria can be helpful in improving a plant's tolerance to salinity. Although plant-bacteria interactions in response to salt stress have been characterized, the precise molecular mechanisms by which bacterial inoculation alleviates salt stress in plants are still poorly explored. In the present study, we aimed to determine the role of a salt-tolerant plant growth-promoting rhizobacteria (PGPR) <i>Sphingobacterium</i> BHU-AV3 for improving salt tolerance in tomato through investig ...[more]

PMID: 32308647

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Project description:Crops around the world are facing a diversity of environmental problems, of which high temperatures are proving to be the most serious threat to crops. Polyamine putrescine (Put) acts as a master growth regulator that contributes to optimal plant growth and development and increased stress tolerance. Here, the current study aimed to elucidate how Put functions in regulating chlorophyll (Chl) metabolism, oxidative stress, and antioxidant defense, as well as to characterize the expression of genes related to heat stress in tomato seedlings under such stress. The results revealed that Put treatment significantly attenuates heat-induced damage by promoting biomass production, increasing photosynthetic efficiency, and inhibiting excessive production of oxidative stress markers. Heat stress markedly decreased the Chl content in the tomato leaf and accelerated the leaf yellowing process. However, Put-treated tomato seedlings showed a higher Chl content, which could be associated with the functions of Put in elevating PBGD activity (Chl biosynthesis enzyme) and suppressing the activity of the Chl catabolic enzyme (Chlase and MDCase). Under high-temperature stress, the expression levels of the gene encoding factors involved in Chl biosynthesis and Chl catabolism were significantly down- and upregulated, respectively, and this trend was reversed in Put-treated heat-stressed seedlings. In addition, exogenous application of Put boosted the activity of antioxidant enzymes, along with the levels of expression of their encoding genes, only in plants that were heat stressed. Furthermore, the expression levels of heat-shock-related genes (HSP90, HSP70, and HsfA1) were elevated in Put-treated, high-temperature-stressed tomato seedlings. Taken together, our results indicate that Put treatment significantly increases the heat tolerance of tomato seedlings, by elevating Chl concentrations and suppressing Chl catabolic enzyme activity, modulating endogenous free PA content, increasing antioxidant defense efficiency, and upregulating the expression of heat-shock-related genes.

Project description:BackgroundExcessive soil salinity is an important problem for agriculture, however, salt tolerance is a complex trait that is not easily bred into plants. Exposure of cultivated tomato to salt stress has been reported to result in increased antioxidant content and activity. Salt tolerance of the related wild species, Solanum pennellii, has also been associated with similar changes in antioxidants. In this work, S. lycopersicum M82, S. pennellii LA716 and a S. pennellii introgression line (IL) population were evaluated for growth and their levels of antioxidant activity (total water-soluble antioxidant activity), major antioxidant compounds (phenolic and flavonoid contents) and antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase and peroxidase) under both control and salt stress (150 mM NaCl) conditions. These data were then used to identify quantitative trait loci (QTL) responsible for controlling the antioxidant parameters under both stress and nonstress conditions.ResultsUnder control conditions, cultivated tomato had higher levels of all antioxidants (except superoxide dismutase) than S. pennellii. However, under salt stress, the wild species showed greater induction of all antioxidants except peroxidase. The ILs showed diverse responses to salinity and proved very useful for the identification of QTL. Thus, 125 loci for antioxidant content under control and salt conditions were detected. Eleven of the total antioxidant activity and phenolic content QTL matched loci identified in an independent study using the same population, thereby reinforcing the validity of the loci. In addition, the growth responses of the ILs were evaluated to identify lines with favorable growth and antioxidant profiles.ConclusionsPlants have a complex antioxidant response when placed under salt stress. Some loci control antioxidant content under all conditions while others are responsible for antioxidant content only under saline or nonsaline conditions. The localization of QTL for these traits and the identification of lines with specific antioxidant and growth responses may be useful for breeding potentially salt tolerant tomato cultivars having higher antioxidant levels under nonstress and salt stress conditions.

Project description:Soil salinity negatively modulates plant growth and development, contributing to severe decreases in the growth and production of crops. Mucilaginibacter sp. K is a root endophytic bacterium that was previously reported by our laboratory to stimulate growth and confer salt tolerance in Arabidopsis (Arabidopsis thaliana). The main purpose of the present study is to elucidate the physiological and molecular machinery responsible for the prospective salt tolerance as imparted by Mucilaginibacter sp. K. We first report that auxin, gibberellin, and MPK6 signalings were required for strain K-induced growth promotion and salt tolerance in Arabidopsis. Then, this strain was assessed as a remediation strategy to improve maize performance under salinity stress. Under normal growth conditions, the seed vigor index, nitrogen content, and plant growth were significantly improved in maize. After NaCl exposure, strain K significantly promoted the growth of maize seedlings, ameliorated decline in chlorophyll content and reduced accretion of MDA and ROS compared with the control. The possible mechanisms involved in salt resistance in maize could be the improved activities of SOD and POD (antioxidative system) and SPS (sucrose biosynthesis), upregulated content of total soluble sugar and ABA, and reduced Na+ accumulation. These physiological changes were then confirmed by induced gene expression for ion transportation, photosynthesis, ABA biosynthesis, and carbon metabolism. In summary, these results suggest that strain K promotes plant growth through increases in photosynthesis and auxin- and MPK6-dependent pathways; it also bestows salt resistance on plants through protection against oxidative toxicity, Na+ imbalance, and osmotic stress, along with the activation of auxin-, gibberellin-, and MPK6-dependent signaling pathways. This is the first detailed report of maize growth promotion by a Mucilaginibacter sp. strain from wild plant. This strain could be used as a favorable biofertilizer and a salinity stress alleviator for maize, with further ascertainment as to its reliability of performance under field conditions and in the presence of salt stress.

Dataset Information

Sphingobacterium sp. BHU-AV3 Induces Salt Tolerance in Tomato by Enhancing Antioxidant Activities and Energy Metabolism.

Publications

<i>Sphingobacterium</i> sp. BHU-AV3 Induces Salt Tolerance in Tomato by Enhancing Antioxidant Activities and Energy Metabolism.

Similar Datasets

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