scholarly journals Current Advances in Plant Growth Promoting Bacteria Alleviating Salt Stress for Sustainable Agriculture

2020 ◽  
Vol 10 (20) ◽  
pp. 7025
Author(s):  
Slimane Mokrani ◽  
El-hafid Nabti ◽  
Cristina Cruz

Humanity in the modern world is confronted with diverse problems at several levels. The environmental concern is probably the most important as it threatens different ecosystems, food, and farming as well as humans, animals, and plants. More specifically, salinization of agricultural soils is a global concern because of on one side, the permanent increase of the areas affected, and on the other side, the disastrous damage caused to various plants affecting hugely crop productivity and yields. Currently, great attention is directed towards the use of Plant Growth Promoting Bacteria (PGPB). This alternative method, which is healthy, safe, and ecological, seems to be very promising in terms of simultaneous salinity alleviation and improving crop productivity. This review attempts to deal with different aspects of the current advances concerning the use of PGPBs for saline stress alleviation. The objective is to explain, discuss, and present the current progress in this area of research. We firstly discuss the implication of PGPB on soil desalinization. We present the impacts of salinity on crops. We look for the different salinity origin and its impacts on plants. We discuss the impacts of salinity on soil. Then, we review various recent progress of hemophilic PGPB for sustainable agriculture. We categorize the mechanisms of PGPB toward salinity tolerance. We discuss the use of PGPB inoculants under salinity that can reduce chemical fertilization. Finally, we present some possible directions for future investigation. It seems that PGPBs use for saline stress alleviation gain more importance, investigations, and applications. Regarding the complexity of the mechanisms implicated in this domain, various aspects remain to be elucidated.

2018 ◽  
Vol 64 (12) ◽  
pp. 968-978 ◽  
Author(s):  
Shiying Zhang ◽  
Cong Fan ◽  
Yongxia Wang ◽  
Yunsheng Xia ◽  
Wei Xiao ◽  
...  

Growth and productivity of rice is negatively affected by soil salinity. However, some salt-tolerant bacteria improve the health of plants under saline stress. In this study, 305 bacteria were isolated from paddy soil in Taoyuan, China. Among these, 162 strains were tested for salt-tolerance; 67.3%, 28.4%, and 9.3% of the strains could grow in media with NaCl concentrations of 50, 100, and 150 g/L, respectively. The phylogenic analysis of 74 of these 162 strains indicates that these bacteria belong to Bacillales (72%), Actinomycetales (22%), Rhizobiales (1%), and Oceanospirillales (4%). Among 162 strains, 30 salt-tolerant strains were screened for their plant-growth-promoting activities under axenic conditions at 3, 6, 9, and 12 g/L NaCl; 43%–97% of the strains could improve rice germination energy or germination capacity, while 63%–87% of the strains could increase shoot and root lengths. Among various plant-growth-promoting bacteria, TY0307 was the most effective strain for promoting the growth of rice, even at high salt stress. Its promotor effects were associated with its production of 1-aminocyclopropane-1-carboxycarboxylate deaminase, indole acetic acid, and siderophores; induction of proline accumulation; and reduction of the salt-induced malondialdehyde content. These results suggest that several strains isolated from paddy soil could improve rice salt tolerance and may be used in the development of biofertilizer.


2021 ◽  
Vol 3 ◽  
Author(s):  
María Florencia Yañez-Yazlle ◽  
Neli Romano-Armada ◽  
Verónica Beatriz Rajal ◽  
Verónica Patricia Irazusta

The rhizosphere and microbiome of halotolerant plants could be crucial for alleviating salinity stress during plant growth. The aims of this work were (1) to isolate bacteria from rhizosphere and bulk soil samples from the Salar del Hombre Muerto (Catamarca, Argentina), (2) to characterize different plant growth-promoting (PGP) activities produced by these bacterial isolates, and (3) to evaluate their effect on the initial growth of chia (Salvia hispanica L.) under saline stress. A total of 667 microorganisms were isolated, using different culture media with NaCl, and their abilities for nitrogen fixation, phosphate solubilization, siderophores production, and indole-3-acetic acid production were evaluated. Thirteen strains were selected for showing all the tested PGP activities; they belonged to the genera Kushneria, Halomonass, Pseudomonas, Planomicrobium, and Pseudarthrobacter. The strains Kushneria sp. and Halomonas sp. showed the highest salinity tolerance (from 50 to 2,000 mM NaCl) and biomass and biofilm production. Chia seeds were treated with six of the first 13 selected strains to evaluate their plant growth-promoting effect under saline stress (without and with 50 and 100 mM NaCl). Halomonas sp. 3R.12 and Kushneria sp. T3.7 produced heavier seedlings with a balanced shoot/root length ratio, while Pseudomonas sp. AN23 showed the best effect upon chia seedlings, with a morphological response similar to non-stressed seedlings. On the other hand, seedlings displayed no responses when inoculated with Planomicrobium sp. 3S.31 and Pseudarthrobacter sp. ER25. This study contributes to the knowledge on microorganisms from hypersaline environments as plant growth promoters for their use in the production of salt-sensitive crops, among other potential uses.


2021 ◽  
Vol 9 (9) ◽  
pp. 1841
Author(s):  
Angelika Fiodor ◽  
Surender Singh ◽  
Kumar Pranaw

Combating the consequences of climate change is extremely important and critical in the context of feeding the world’s population. Crop simulation models have been extensively studied recently to investigate the impact of climate change on agricultural productivity and food security. Drought and salinity are major environmental stresses that cause changes in the physiological, biochemical, and molecular processes in plants, resulting in significant crop productivity losses. Excessive use of chemicals has become a severe threat to human health and the environment. The use of beneficial microorganisms is an environmentally friendly method of increasing crop yield under environmental stress conditions. These microbes enhance plant growth through various mechanisms such as production of hormones, ACC deaminase, VOCs and EPS, and modulate hormone synthesis and other metabolites in plants. This review aims to decipher the effect of plant growth promoting bacteria (PGPB) on plant health under abiotic soil stresses associated with global climate change (viz., drought and salinity). The application of stress-resistant PGPB may not only help in the combating the effects of abiotic stressors, but also lead to mitigation of climate change. More thorough molecular level studies are needed in the future to assess their cumulative influence on plant development.


2012 ◽  
Vol 61 ◽  
pp. 264-272 ◽  
Author(s):  
Daniel Rojas-Tapias ◽  
Andrés Moreno-Galván ◽  
Sergio Pardo-Díaz ◽  
Melissa Obando ◽  
Diego Rivera ◽  
...  

2020 ◽  
Vol 12 (23) ◽  
pp. 9917
Author(s):  
Marika Pellegrini ◽  
Giancarlo Pagnani ◽  
Matteo Bernardi ◽  
Alessandro Mattedi ◽  
Daniela M. Spera ◽  
...  

Plant growth-promoting bacteria (PGPB) afford plants several advantages (i.e., improvement of nutrient acquisition, growth, and development; induction of abiotic and biotic stress tolerance). Numerous PGPB strains have been isolated and studied over the years. However, only a few of them are available on the market, mainly due to the failed bacterial survival within the formulations and after application inside agroecosystems. PGPB strains with these challenging limitations can be used for the formulation of cell-free supernatants (CFSs), broth cultures processed through several mechanical and physical processes for cell removal. In the scientific literature there are diverse reviews and updates on PGPB in agriculture. However, no review deals with CFSs and the CFS metabolites obtainable by PGPB. The main objective of this review is to provide useful information for future research on CFSs as biostimulant and biocontrol agents in sustainable agriculture. Studies on CFS agricultural applications, both for biostimulant and biocontrol applications, have been reviewed, presenting limitations and advantages. Among the 109 articles selected and examined, the Bacillus genus seems to be the most promising due to the numerous articles that support its biostimulant and biocontrol potentialities. The present review underlines that research about this topic needs to be encouraged; evidence so far obtained has demonstrated that PGPB could be a valid source of secondary metabolites useful in sustainable agriculture.


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