scholarly journals Arbuscular Mycorrhiza and Plant Growth-promoting Bacteria Alleviate Drought Stress in Walnut

HortScience ◽  
2019 ◽  
Vol 54 (6) ◽  
pp. 1087-1092 ◽  
Author(s):  
Azadeh Behrooz ◽  
Kourosh Vahdati ◽  
Farhad Rejali ◽  
Mahmoud Lotfi ◽  
Saadat Sarikhani ◽  
...  

Drought stress is one of the main constraints limiting worldwide crop production. Arbuscular mycorrhizae (AM) and plant growth-promoting bacteria (PGPB) such as Azotobacter chroococcum and Azospirillium lipofrum have been shown to alleviate drought stress effects. Therefore, the interaction effect of AM fungi [Glomus mosseae, G. etunicatum, and a mix of these (G. mix), and PGPB bacteria (Azotobacter chroococcum + Azospirillium lipofrum)] was investigated in 1-year-old walnut seedlings (cv. Chandler) under normal and drought stress conditions. Drought stress reduced growth (plant height, root length, number of leaves, and fresh weight) and leaf nutrient content (N, P, and Zn) significantly of walnut plants. In contrast, proline, total soluble sugar, starch peroxidase enzyme activity, and total phenolic content of walnut leaves increased under this stress. Application of fungi or bacteria, and especially their simultaneous use, alleviated the negative effects of drought stress on walnut seedlings. AM fungi and PGPB increased significantly the content of some metabolites, including total phenolic content, proline level, peroxidase activity, total soluble sugar, and starch content as well as peroxidase enzyme activity. This led to an increase in walnut plant growth under the drought stress condition. Among AM fungi, G. etunicatum was more effective in reducing drought stress symptoms than either G. mosseae or the G. mix of fungi. In conclusion, use of G. etunicatum, along with PGPB, can reduce negative effects of drought stress on walnut seedlings.

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.


Author(s):  
Thắng Thanh Trần

Peanut is am essential legume and has many uses, such as producing oil, food, and fodder. However, with the negative effects of climate change, drought is one especially of the important issues that reduce the yield of peanut. Thus, in this study, the impact of drought stress on the peanut growth was investigated by using PEG-6000 to block pathways of water movement. The changes in morphological, physiological, and biochemical during the peanut growth under drought were analyzed. In the drought condition (-2 bar), the germination time of seed increased but the percentage of germination seeds decreased by approximately 50% compared to control. Besides, the shoot height, the number of leaves, the total leaf area, root length, and fresh weight were lower than that of control. Drought stress made the formation quickly of secondary xylem and phloem. Also, the process of lignification in the phloem parenchyma cell increased. These cell walls were much thicker than those in the control root. In the drought stress, the physiological and biochemical analysis showed that the content of chlorophyll a, leaf relative water content, and starch content reduced significantly in comparison to control. Similarly, the photosynthetic intensity, the activity of cytokinin, and gibberellin decreased. The reverse pattern can be seen in the content of carotenoid, epicuticular wax, proline, and total soluble sugar, respiratory intensity, the activity of catalase, auxin, and ABA activity.


2012 ◽  
Vol 32 (1) ◽  
pp. 122-130 ◽  
Author(s):  
Wedad A. Kasim ◽  
Mohammed E. Osman ◽  
Mohammed N. Omar ◽  
Islam A. Abd El-Daim ◽  
Sarosh Bejai ◽  
...  

2019 ◽  
Vol 76 (11) ◽  
pp. 1345-1354 ◽  
Author(s):  
Leticia B. Pereira ◽  
Gabriela S. Andrade ◽  
Silvana P. Meneghin ◽  
Renato Vicentini ◽  
Laura M. M. Ottoboni

2021 ◽  
Vol 9 (3) ◽  
pp. 639
Author(s):  
Marika Pellegrini ◽  
Daniela M. Spera ◽  
Claudia Ercole ◽  
Maddalena Del Gallo

The present work was aimed at investigating the effects of a four bacterial strain consortium—Azospirillum brasilense, Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, and Burkholderia ambifaria—on Allium cepa L. and on soil health. The bacterial consortium was inoculated on seeds of two different onion varieties; inoculated and Control seeds (treated with autoclaved inoculum) were sown in an open-field and followed until harvest. Plant growth development parameters, as well as soil physico–chemical and molecular profiles (DNA extraction and 16S community sequencing on the Mi-Seq Illumina platform), were investigated. The results showed a positive influence of bacterial application on plant growth, with increased plant height (+18%), total chlorophylls (+42%), crop yields (+13%), and bulb dry matter (+3%) with respect to the Control. The differences between Control and treatments were also underlined in the bulb extracts in terms of total phenolic contents (+25%) and antioxidant activities (+20%). Soil fertility and microbial community structure and diversity were also positively affected by the bacterial inoculum. At harvest, the soil with the presence of the bacterial consortium showed an increase in total organic carbon, organic matter, and available phosphorus, as well as higher concentrations of nutrients than the Control. The ecological indexes calculated from the molecular profiles showed that community diversity was positively affected by the bacterial treatment. The present work showed the effective use of plant growth-promoting bacteria as a valid fertilization strategy to improve yield in productive landscapes whilst safeguarding soil biodiversity.


2021 ◽  
pp. 593-610
Author(s):  
Chinenyenwa Fortune Chukwuneme ◽  
Ifeyinwa Monica Uzoh ◽  
Funso Raphael Kutu ◽  
Olubukola Oluranti Babalola

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 520
Author(s):  
Khaled Abdelaal ◽  
Muneera AlKahtani ◽  
Kotb Attia ◽  
Yaser Hafez ◽  
Lóránt Király ◽  
...  

Plant growth-promoting bacteria play an essential role in enhancing the physical, chemical and biological characters of soils by facilitating nutrient uptake and water flow, especially under abiotic stress conditions, which are major constrains to agricultural development and production. Drought is one of the most harmful abiotic stress and perhaps the most severe problem facing agricultural sustainability, leading to a severe shortage in crop productivity. Drought affects plant growth by causing hormonal and membrane stability perturbations, nutrient imbalance and physiological disorders. Furthermore, drought causes a remarkable decrease in leaf numbers, relative water content, sugar yield, root yield, chlorophyll a and b and ascorbic acid concentrations. However, the concentrations of total phenolic compounds, electrolyte leakage, lipid peroxidation, amounts of proline, and reactive oxygen species are considerably increased because of drought stress. This negative impact of drought can be eliminated by using plant growth-promoting bacteria (PGPB). Under drought conditions, application of PGPB can improve plant growth by adjusting hormonal balance, maintaining nutrient status and producing plant growth regulators. This role of PGPB positively affects physiological and biochemical characteristics, resulting in increased leaf numbers, sugar yield, relative water content, amounts of photosynthetic pigments and ascorbic acid. Conversely, lipid peroxidation, electrolyte leakage and amounts of proline, total phenolic compounds and reactive oxygen species are decreased under drought in the presence of PGPB. The current review gives an overview on the impact of drought on plants and the pivotal role of PGPB in mitigating the negative effects of drought by enhancing antioxidant defense systems and increasing plant growth and yield to improve sustainable agriculture.


2019 ◽  
Vol 65 (2) ◽  
pp. 91-104 ◽  
Author(s):  
Pilar Martínez-Hidalgo ◽  
Maskit Maymon ◽  
Flora Pule-Meulenberg ◽  
Ann M. Hirsch

The Green Revolution developed new crop varieties, which greatly improved food security worldwide. However, the growth of these plants relied heavily on chemical fertilizers and pesticides, which have led to an overuse of synthetic fertilizers, insecticides, and herbicides with serious environmental consequences and negative effects on human health. Environmentally friendly plant-growth-promoting methods to replace our current reliance on synthetic chemicals and to develop more sustainable agricultural practices to offset the damage caused by many agrochemicals are proposed herein. The increased use of bioinoculants, which consist of microorganisms that establish synergies with target crops and influence production and yield by enhancing plant growth, controlling disease, and providing critical mineral nutrients, is a potential solution. The microorganisms found in bioinoculants are often bacteria or fungi that reside within either external or internal plant microbiomes. However, before they can be used routinely in agriculture, these microbes must be confirmed as nonpathogenic strains that promote plant growth and survival. In this article, besides describing approaches for discovering plant-growth-promoting bacteria in various environments, including phytomicrobiomes and soils, we also discuss methods to evaluate their safety for the environment and for human health.


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