scholarly journals The Role of Trichoderma Species in Plants Response to Salt Stress

Author(s):  
Solomon Boamah ◽  
Shuwu Zhang ◽  
Bingliang Xu ◽  
LI Tong ◽  
Rehan Inayat ◽  
...  

Soil salinity is a pending threat to global agricultural sustainability and food security. The natural means of alleviating this stress have become the major concern as to which methods, mechanisms, and organisms to be used.  Soil-borne fungi Trichoderma has proven to alleviate salinity stress in plants. This review aimed to shed light on the roles and mechanisms of some species of Trichoderma in response to salt stress and other merits to plant growth and development. Detailed of this research reviewed the level of growth promotion induced by Trichoderma species with an estimated increase of 200% of total plant biomass compared with control plants from literature. The defined mechanisms of Trichoderma in combating salinity stress in plants are; formation of ion channels in host plants, activation of ion exchange (K+/N+), increase Reactive Oxygen Species (ROS) scavenging enzymes, antioxidants, and genes, production of phytohormones and their signal pathways, stimulates root formation and developments, regulate stomata conductance through the increment of carotenoids in host plants which corresponds to the functions of the photosystems.

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 989 ◽  
Author(s):  
Noshin Ilyas ◽  
Roomina Mazhar ◽  
Humaira Yasmin ◽  
Wajiha Khan ◽  
Sumera Iqbal ◽  
...  

Halo-tolerant plant growth-promoting rhizobacteria (PGPR) have the inherent potential to cope up with salinity. Thus, they can be used as an effective strategy in enhancing the productivity of saline agro-systems. In this study, a total of 50 isolates were screened from the rhizospheric soil of plants growing in the salt range of Pakistan. Out of these, four isolates were selected based on their salinity tolerance and plant growth promotion characters. These isolates (SR1. SR2, SR3, and SR4) were identified as Bacillus sp. (KF719179), Azospirillum brasilense (KJ194586), Azospirillum lipoferum (KJ434039), and Pseudomonas stutzeri (KJ685889) by 16S rDNA gene sequence analysis. In vitro, these strains, in alone and in a consortium, showed better production of compatible solute and phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), cytokinin (CK), and abscisic acid (ABA), in culture conditions under salt stress. When tested for inoculation, the consortium of all four strains showed the best results in terms of improved plant biomass and relative water content. Consortium-inoculated wheat plants showed tolerance by reduced electrolyte leakage and increased production of chlorophyll a, b, and total chlorophyll, and osmolytes, including soluble sugar, proline, amino acids, and antioxidant enzymes (superoxide dismutase, catalase, peroxidase), upon exposure to salinity stress (150 mM NaCl). In conclusion, plant growth-promoting bacteria, isolated from salt-affected regions, have strong potential to mitigate the deleterious effects of salt stress in wheat crop, when inoculated. Therefore, this consortium can be used as potent inoculants for wheat crop under prevailing stress conditions.


2021 ◽  
Author(s):  
Julio Armando Massange-Sánchez ◽  
Carla Vanessa Sánchez-Hernández ◽  
Rosalba Mireya Hernández-Herrera ◽  
Paola Andrea Palmeros-Suárez

Salinity is one of the most severe environmental problems worldwide and affects plant growth, reproduction, and crop yields by inducing physiological and biochemical changes due to osmotic and ionic shifts in plant cells. One of the principal modifications caused by osmotic stress is the accumulation of reactive oxygen species (ROS), which cause membrane damage and alter proteins, DNA structures, and photosynthetic processes. In response, plants increase their arsenal of antioxidant compounds, such as ROS scavenging enzymes and nonenzymatic elements like ascorbate, glutathione, flavonoids, tocopherols, and carotenoids, and their rates of osmolyte synthesis to conserve ion homeostasis and manage salt stress. This chapter describes the principal biochemical mechanisms that are employed by plants to survive under salt-stress conditions, including the most recent research regarding plant tolerance, and suggests strategies to produce valuable crops that are able to deal with soil salinity.


Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 406 ◽  
Author(s):  
Xingmin Geng ◽  
Yuemiao Zhang ◽  
Lianggui Wang ◽  
Xiulian Yang

The landscape application of sweet osmanthus (Osmanthus fragrans) with flower fragrance and high ornamental value is severely limited by salinity stress. Gamma irradiation applied to seeds enhanced their tolerance to salinity stress as reported in other plants. In this study, O. fragrans ‘Huangchuang Jingui’ seeds were pretreated with different doses of gamma irradiation, and tolerance of the seedlings germinated from the irradiated seeds to salinity stress and the changes of reactive oxygen species (ROS) production and ROS scavenging systems induced by gamma irradiation were observed. The results showed that seed pretreatment with different doses of gamma irradiation enhanced the tolerance of sweet osmanthus seedlings to salinity stress, and the positive effect induced by gamma irradiation was more remarkable with the increase of radiation dose (50–150 Gy). The pretreatment with high-dose irradiation decreased O2− production under salinity stress and mitigated the oxidative damage marked by a lower malondialdehyde (MDA) level, which could be related to the significant increase of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in the seedlings germinated from the irradiated seeds compared to the corresponding control seedlings. In addition, the accumulation of proline in the irradiated seedlings may contribute to enhancing their tolerance to salt stress by the osmotic adjustment. The study demonstrated the importance of regulating plant ROS balance under salt stress and provided a potential approach to improve the tolerance of sweet osmanthus to salt stress.


2019 ◽  
Vol 20 (15) ◽  
pp. 3729 ◽  
Author(s):  
Shuwu Zhang ◽  
Bingliang Xu ◽  
Yantai Gan

Salt stress is one of the major abiotic stresses limiting crop growth and productivity worldwide. Species of Trichoderma are widely recognized for their bio-control abilities, but little information is regarding to the ability and mechanisms of their promoting plant growth and enhancing plant tolerance to different levels of salt stress. Hence, we determined (i) the role of Trichoderma longibrachiatum T6 (TL-6) in promoting wheat (Triticum aestivum L.) seed germination and seedling growth under different levels of salt stress, and (ii) the mechanisms responsible for the enhanced tolerance of wheat to salt stress by TL-6. Wheat seeds treated with or without TL-6 were grown under different levels of salt stress in controlled environmental conditions. As such, the TL-6 treatments promoted seed germination and increased the shoot and root weights of wheat seedlings under both non-stress and salt-stress conditions. Wheat seedlings with TL-6 treatments under different levels of NaCl stress increased proline content by an average of 11%, ascorbate 15%, and glutathione 28%; and decreased the contents of malondialdehyde (MDA) by an average of 19% and hydrogen peroxide (H2O2) 13%. The TL-6 treatments induced the transcriptional level of reactive oxygen species (ROS) scavenging enzymes, leading to the increases of glutathione s-transferase (GST) by an average of 17%, glutathione peroxidase (GPX) 16%, ascorbate peroxidase (APX) 17%, glutathione reductase (GR) 18%, dehydroascorbate reductase (DHAR) 5%. Our results indicate that the beneficial strain of TL-6 effectively scavenged ROS under NaCl stress through modulating the activity of ROS scavenging enzymes, regulating the transcriptional levels of ROS scavenging enzyme gene expression, and enhancing the nonenzymatic antioxidants in wheat seedling in response to salt stress. Our present study provides a new insight into the mechanisms of TL-6 can activate the enzymatic and nonenzymatic antioxidant defense systems and enhance wheat seedling tolerance to different levels of salt stress at physiological, biochemical and molecular levels.


2019 ◽  
Vol 20 (3) ◽  
pp. 788 ◽  
Author(s):  
Tingting Jia ◽  
Jian Wang ◽  
Wei Chang ◽  
Xiaoxu Fan ◽  
Xin Sui ◽  
...  

To reveal the mechanism of salinity stress alleviation by arbuscular mycorrhizal fungi (AMF), we investigated the growth parameter, soluble sugar, soluble protein, and protein abundance pattern of E. angustifolia seedlings that were cultured under salinity stress (300 mmol/L NaCl) and inoculated by Rhizophagus irregularis (RI). Furthermore, a label-free quantitative proteomics approach was used to reveal the stress-responsive proteins in the leaves of E. angustifolia. The result indicates that the abundance of 75 proteins in the leaves was significantly influenced when E. angustifolia was inoculated with AMF, which were mainly involved in the metabolism, signal transduction, and reactive oxygen species (ROS) scavenging. Furthermore, we identified chorismate mutase, elongation factor mitochondrial, peptidyl-prolyl cis-trans isomerase, calcium-dependent kinase, glutathione S-transferase, glutathione peroxidase, NADH dehydrogenase, alkaline neutral invertase, peroxidase, and other proteins closely related to the salt tolerance process. The proteomic results indicated that E. angustifolia seedlings inoculated with AMF increased the secondary metabolism level of phenylpropane metabolism, enhanced the signal transduction of Ca2+ and ROS scavenging ability, promoted the biosynthesis of protein, accelerated the protein folding, and inhibited the degradation of protein under salt stress. Moreover, AMF enhanced the synthesis of ATP and provided sufficient energy for plant cell activity. This study implied that symbiosis of halophytes and AMF has potential as an application for the improvement of saline-alkali soils.


Author(s):  
Deyu Mu ◽  
Chen Ding

Elevated salinity is one of the major environmental limitation factors of plant growth and development and salinity stress compromises the production and survival of plantation and urban forests and agricultural crops in the arid, semi-arid, and intertidal zones. Ulmus pumila, a salt- indigenous tree species in Asia and is widely deployed in salt-affected areas in China, and U.pumila is promising for multi-varietal forestry in plantation and urban forests. The comprehensive mechanism of the intraspecific salt tolerance is still not clear yet. Here, we investigated the physiological responses of the salinity stress based on the antioxidant enzyme activities, osmotic adjustments, and gas exchange among salt-tolerant U. pumila genotypes for 100 days under five different NaCl levels (0%, 0.3%, 0.5%, 0.7%, and 0.9% w/v) with natural surroundings and rain shade at age-2. Salt stress decreased height (HR), ground diameter (DR), and dry weight (biomass) were significantly different among genotypes. HR and performance indices were positively correlated with photosynthesis rate (Pn), apparent mesophyll conductance (AMC), and chlorophyll (CHLL) with (r= 0.7 - 0.8 ***), but were negatively related to the free proline, sugar, and protein accumulation (r=-0.5 ~ -0.7***). We found that high accumulation of sugars and more activities of SOD enzyme in leaf tissue contribute to the osmotic adjustment and ROS scavenging system under salinity treatment; the sugar content and SOD activity play key roles in U. pumila’s tolerance to salt stress, and are promising indicators for U. pumila species ex vitro selections. The ex vitro selection results align with the previous in vitro studies [37] and is promising for the MVF development.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tingting Sun ◽  
Tingting Pei ◽  
Lulu Yang ◽  
Zhijun Zhang ◽  
Mingjun Li ◽  
...  

Abstract Background Soil salinity is a critical threat to global agriculture. In plants, the accumulation of xanthine activates xanthine dehydrogenase (XDH), which catalyses the oxidation/conversion of xanthine to uric acid to remove excess reactive oxygen species (ROS). The nucleobase-ascorbate transporter (NAT) family is also known as the nucleobase-cation symporter (NCS) or AzgA-like family. NAT is known to transport xanthine and uric acid in plants. The expression of MdNAT is influenced by salinity stress in apple. Results In this study, we discovered that exogenous application of xanthine and uric acid enhanced the resistance of apple plants to salinity stress. In addition, MdNAT7 overexpression transgenic apple plants showed enhanced xanthine and uric acid concentrations and improved tolerance to salinity stress compared with nontransgenic plants, while opposite phenotypes were observed for MdNAT7 RNAi plants. These differences were probably due to the enhancement or impairment of ROS scavenging and ion homeostasis abilities. Conclusion Our results demonstrate that xanthine and uric acid have potential uses in salt stress alleviation, and MdNAT7 can be utilized as a candidate gene to engineer resistance to salt stress in plants.


2020 ◽  
Vol 127 (6) ◽  
pp. 769-781 ◽  
Author(s):  
Ibrahim Alabid ◽  
Martin Hardt ◽  
Jafargholi Imani ◽  
Anton Hartmann ◽  
Michael Rothballer ◽  
...  

Abstract The Alphaproteobacterium Rhizobium radiobacter (syn. Agrobacterium tumefaciens, “A. fa brum”) can live in close association with the sebacinoid fungus Serendipita (syn. Piriformospora) indica that forms a mutualistic Sebacinalean symbiosis with a wide range of host plants. The endobacterial strain R. radiobacter F4 (RrF4), which was originally isolated from the fungus, has plant growth promotion and resistance-inducing activities resembling the beneficial activities known from the endobacteria-containing S. indica. The mechanism by which free endobacterial cells influence growth and disease resistance of colonized host plants is not fully understood. Here, we show that RrF4 produces a spectrum of quorum sensing-mediating N-acyl-homoserine lactones (AHLs) with acyl chains of C8, C10, and C12 as well as hydroxyl- or oxo-substitutions at the C3 position. In addition, and in line with previous findings showing that AHLs increase plant biomass and induce systemic resistance, the AHL-depleted lactonase-overexpressing transconjugant RrF4NM13 was partially compromised in promoting growth and inducing resistance against bacterial pathogens in both Arabidopsis thaliana and wheat (Triticum aestivum). Scanning and transmission electron microscopy proved that RrF4NM13, in contrast to RrF4, does not form cellulose-like fiber scaffolds for efficient root surface attachment. Moreover, RrF4NM13 does not penetrate into the intercellular space of the cortical tissue, which in contrast is strongly colonized by RrF4. We discuss the possibility that AHLs contribute to the outcome of the Sebacinalean symbiosis.


2020 ◽  
Vol 10 (17) ◽  
pp. 5767 ◽  
Author(s):  
Elisa Gamalero ◽  
Nicoletta Favale ◽  
Elisa Bona ◽  
Giorgia Novello ◽  
Patrizia Cesaro ◽  
...  

Bacterial endophytes can colonize plant tissues without harming the plant. Instead, they are often able to increase plant growth and tolerance to environmental stresses. In this work, new strains of bacterial endophytes were isolated from three economically important crop plants (sorghum, cucumber and tomato) grown in three different regions in soils with different management. All bacterial strains were identified by 16S rRNA sequencing and characterized for plant beneficial traits. Based on physiological activities, we selected eight strains that were further tested for their antibiotic resistance profile and for the ability to efficiently colonize the interior of sorghum plants. According to the results of the re-inoculation test, five strains were used to inoculate sorghum seeds. Then, plant growth promotion activity was assessed on sorghum plants exposed to salinity stress. Only two bacterial endophytes increased plant biomass, but three of them delayed or reduced plant salinity stress symptoms. These five strains were then characterized for the ability to produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which is involved in the increase of stress tolerance. Pseudomonas brassicacearum SVB6R1 was the only strain that was able to produce this enzyme, suggesting that ACC deaminase is not the only physiological trait involved in conferring plant tolerance to salt stress in these bacterial strains.


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