scholarly journals Effects of Plant Growth Promoting Rhizobacteria on the Content of Abscisic Acid and Salt Resistance of Wheat Plants

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1429
Author(s):  
Tatiana Arkhipova ◽  
Elena Martynenko ◽  
Guzel Sharipova ◽  
Ludmila Kuzmina ◽  
Igor Ivanov ◽  
...  

Although salinity inhibits plant growth, application of appropriate rhizosphere bacteria can diminish this negative effect. We studied one possible mechanism that may underlie this beneficial response. Wheat plants were inoculated with Bacillus subtilis IB-22 and Pseudomonas mandelii IB-Ki14 and their consequences for growth, water relations, and concentrations of the hormone abscisic acid (ABA) were followed in the presence of soil salinity. Salinity alone increased ABA concentration in wheat leaves and roots and this was associated with decreased stomatal conductance, but also with chlorophyll loss. Bacterial treatment raised ABA concentrations in roots, suppressed accumulation of leaf ABA, decreased chlorophyll loss, and promoted leaf area and transpiration. However, water balance was maintained due to increased water uptake by inoculated plants, brought about in part by a larger root system. The effect may be the outcome of ABA action since the hormone is known to maintain root extension in stressed plants. Root ABA concentration was highest in salt-stressed plants inoculated with B. subtilis and this contributed to greater root hydraulic conductivity. We conclude that bacteria can raise salt resistance in wheat by increasing root ABA, resulting in larger root systems that can also possess enhanced hydraulic conductivity thereby supporting better-hydrated leaves.

2020 ◽  
Vol 66 (2) ◽  
pp. 144-160 ◽  
Author(s):  
Shahnaz Sultana ◽  
Sumonta C. Paul ◽  
Samia Parveen ◽  
Saiful Alam ◽  
Naziza Rahman ◽  
...  

Growth and productivity of rice are negatively affected by soil salinity. However, some salt-tolerant rhizosphere-inhabiting bacteria can improve salt resistance of plants, thereby augmenting plant growth and production. Here, we isolated a total of 53 plant-growth-promoting rhizobacteria (PGPR) from saline and non-saline areas in Bangladesh where electrical conductivity was measured as >7.45 and <1.80 dS/m, respectively. Bacteria isolated from saline areas were able to grow in a salt concentration of up to 2.60 mol/L, contrary to the isolates collected from non-saline areas that did not survive beyond 854 mmol/L. Among the salt-tolerant isolates, Bacillus aryabhattai, Achromobacter denitrificans, and Ochrobactrum intermedium, identified by comparing respective sequences of 16S rRNA using the NCBI GenBank, exhibited a higher amount of atmospheric nitrogen fixation, phosphate solubilization, and indoleacetic acid production at 200 mmol/L salt stress. Salt-tolerant isolates exhibited greater resistance to heavy metals and antibiotics, which could be due to the production of an exopolysaccharide layer outside the cell surface. Oryza sativa L. fertilized with B. aryabhattai MS3 and grown under 200 mmol/L salt stress was found to be favoured by enhanced expression of a set of at least four salt-responsive plant genes: BZ8, SOS1, GIG, and NHX1. Fertilization of rice with osmoprotectant-producing PGPR, therefore, could be a climate-change-preparedness strategy for coastal agriculture.


Author(s):  
Abu Sayeed Md. Hasibuzzaman ◽  
Farzana Akter ◽  
Shamim Ara Bagum ◽  
Nilima Hossain ◽  
Tahmina Akter ◽  
...  

Maize is one of the mostly consumed grains in the world. It possesses a greater potentiality of being an alternative to rice and wheat in the near future. In field condition, maize encounters abiotic stresses like salinity, drought, water logging, cold, heat, etc. Physiology and production of maize are largely affected by drought. Drought has become a prime cause of agricultural disaster because of the major occurrence records of the last few decades. It leads to immense losses in plant growth (plant height and stem), water relations (relative water content), gas exchange (photosynthesis, stomatal conductance, and transpiration rate), and nutrient levels in maize. To mitigate the effect of stress, plant retreats by using multiple morphological, molecular, and physiological mechanisms. Maize alters its physiological processes like photosynthesis, oxidoreductase activities, carbohydrate metabolism, nutrient metabolism, and other drought-responsive pathways in response to drought. Synthesis of some chemicals like proline, abscisic acid (ABA), different phenolic compounds, etc. helps to fight against stress. Inoculation of plant growth-promoting rhizobacteria (PGPR) can result to the gene expression involved in the biosynthesis of abscisic acid which also helps to resist drought. Moreover, adaptation to drought and heat stress is positively influenced by the activity of chaperone proteins and proteases, protein that responds to ethylene and ripening. Some modifications generated by clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 are able to improve maize yield in drought. Forward and reverse genetics and functional and comparative genomics are being implemented now to overcome stress conditions like drought. Maize response to drought is a multifarious physiological and biochemical process. Applying data synthesis approach, this study aims toward better demonstration of its consequences to provide critical information on maize tolerance along with minimizing yield loss.


2009 ◽  
Vol 55 (11) ◽  
pp. 1302-1309 ◽  
Author(s):  
Sajid Mahmood Nadeem ◽  
Zahir Ahmad Zahir ◽  
Muhammad Naveed ◽  
Muhammad Arshad

Salt stress is one of the major constraints hampering agricultural production owing to its impact on ethylene production and nutritional imbalance. A check on the accelerated ethylene production in plants could be helpful in minimizing the negative effect of salt stress on plant growth and development. Four Pseudomonas , 1 Flavobacterium , and 1 Enterobacter strain of plant growth promoting rhizobacteria containing 1-aminocyclopropane-1-carboxylate (ACC)-deaminase were selected and their effects on growth and yield of maize were investigated to improve the salt tolerance of maize grown on salt-affected fields. The selected rhizobacterial isolates reduced or eliminated the classical “triple” response, indicating their ability to reduce stress-induced ethylene levels. Results showed that rhizobacterial strains, particularly Pseudomonas and Enterobacter spp., significantly promoted the growth and yield of maize compared with the non-inoculated control. Pseudomonas fluorescens increased plant height, biomass, cob yield, grain yield, 1000 grain mass, and straw yield of maize up to 29%, 127%, 67%, 60%, 17%, and 166%, respectively, over the control. Under stress conditions, more N, P, and K uptake and high K+–Na+ ratios were recorded in inoculated plants compared with the control. The results imply that inoculation with plant growth promoting rhizobacteria containing ACC-deaminase could be a useful approach for improving growth and yield of maize under salt-stressed conditions.


Author(s):  
Arghavan Salimi ◽  
Mohammad Etemadi ◽  
Saeid Eshghi ◽  
Akbar Karami ◽  
Javad Alizargar

The role of plant growth-promoting rhizobacteria (PGPR) on enhancing tolerance of plants to abiotic stresses is well reported, but the effects of RGPRs on plants under salinity stress are not widely studied in the literature. Our study aimed to investigate the effect of Halomonas sp. and Azotobacter sp. on antioxidant activity, secondary metabolites, and biochemicals changes of purple basil under salinity stress conditions. The applied salt concentrations in this study were 50, 100, and 150 mM sodium chloride (NaCl). Salinity stress had a negative effect on plant growth parameters. Moreover, a reduction in some of the osmolytes and oxidative stress markers was observed. Inoculated plants ameliorated the oxidative damage by reducing the hydrogen peroxide (H2O2) contents and by increasing osmolytes (proline, total proteins, and soluble sugars), antioxidant enzymes activities (catalase, ascorbate peroxidase) and secondary metabolites (flavonoids). Overall, among treatments, plants inoculated with Azotobacter showed a better impact on physiological attributes to alleviate the adverse effects of 150 mM NaCl salinity stress on basil growth.


Author(s):  
Hossein Zahedi ◽  
Samira Abbasi

The effect of inoculation of three plant growth promoting rhizobacteria (PGPR) that is <italic>Rhizobium japonicum</italic>, <italic>Azotobacter chroococcum</italic> and <italic>Azospirillum brasilense</italic> and mixture of them on phytohormones and polyamines of soybean under different irrigation regimes was investigated. Drought stress induced by irrigation withholding until 40, 80 and 120 mm evaporation from evaporation pan. However seed bacterization of soybean was accompanied with 20 kg ha<sup>−1</sup> nitrogen. In addition, 20 and 100 kg ha<sup>−1</sup> nitrogen were considered as control treatments. The results showed that drought stress significantly decreased cytokinin, gibberellin and auxin accumulation in plant tissues. By contrast, drought stress led to increase in abscisic acid accumulation in soybean plants. Polyamines that are putrescine and spermidine increased due to drought stress and then decreased under severe drought stress. PGPR application had positive effect on growth promoting phytohormones compared to control treatment. However the highest accumulation of cytokinin, gibberellin and auxin was related to 100 kg ha<sup>−1</sup> nitrogen treatment. In case of abscisic acid PGPR application decreased its accumulation. Asignificant decrease as observed on polyamines accumulation when PGPRs were applied on stressed soybean plants.


2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Jieli Peng ◽  
Jia Ma ◽  
Xiaoyan Wei ◽  
Cuimian Zhang ◽  
Nan Jia ◽  
...  

Abstract Purpose Salt stress reduces plant growth and is now becoming one of the most important factors restricting the agricultural productivity. Inoculation of plant growth-promoting rhizobacteria (PGPR) has been shown to confer plant tolerance against abiotic stress, but the detailed mechanisms of how this occurs remain unclear and the application effects in different reports are unstable. In order to obtain a favorite effect of PGPR inoculation and improve our knowledge about the related mechanism, we performed this study to analyze the mechanism of a PGPR consortium on improving the salt resistance of crops. Methods A region-specific (Saline land around Bohai Sea in China) PGPR consortium was selected that contains three strains (Pseudomonas sp. P8, Peribacillus sp. P10, and Streptomyces sp. X52) isolated from rhizosphere of Sonchus brachyotus DC. grown in a saline soil. By inoculation tests, their plant growth-promoting (PGP) traits and ability to improve the salt resistance of maize were investigated and shifting in rhizosphere bacterial community of the inoculated plants was analyzed using the high-throughput sequencing technology. Results The three selected strains were salt tolerant, presented several growth promoting properties, and inhibited several phytopathogenic fungi. The inoculation of this consortium promoted the growth of maize plant and enriched the beneficial bacteria in rhizosphere of maize in a saline soil, including the nitrogen fixing bacteria Azotobacter, Sinorhizobium, and Devosia, and the nitrification bacteria Candidatus Nitrososphaera, and Nitrosovibrio. Conclusions The bacterial consortium P8/P10/X52 could improve plant growth in a saline soil by both their PGP traits and regulating the rhizosphere bacterial community. The findings provided novel information about how the PGPR helped the plants in the view of microbiome.


2020 ◽  
Vol 21 (1) ◽  
pp. 14-19
Author(s):  
Praptiningsih Gamawati Adinurani ◽  
Sri Rahayu ◽  
Nurul Fima Zahroh

Mikroba Bacillus subtilis merupakan agen pengendali hayati mempunyai kelebihan sebagai Plant Growth Promoting Rhizobacteria (PGPR) yaitu dapat berfungsi sebagai biofertilizer, biostimulan, biodekomposer dan bioprotektan. Tujuan penelitian mengetahui potensi B. subtilis dalam merombak bahan organik sebagai usaha meningkatkan ketersediaan bahan organik tanah yang semakin menurun. Penelitian menggunakan Rancangan Petak Terbagi dengan berbagai  bahan organik sebagai petak utama (B0 = tanpa bahan organik, B1 = kotoran ayam,  B2 = kotoran kambing, B3 = kotoran sapi) dan aplikasi B.subtilis sebagai anak petak (A0 = 0 cc/L, A1 = 5cc/L, A2 = 10 cc/L, Pengamatan meliputi variabel tinggi tanaman, indeks luas daun, jumlah buah per tanaman, berat buah per tanaman, dan bahan organik tanah. Data pengamatan  dianalisis ragam  menggunakan  Statistical Product and Service Solutions (SPSS) versi 25 dan dilanjutkan dengan uji Duncan untuk mengetahui signifikansi perbedaan antar perlakuan. Hasil penelitian menunjukkan tidak terdapat interaksi antara bahan organik kotoran ternak dan konsentrasi B. subtilis terhadap semua variabel pengamatan. Potensi B. subtilis sangat baik dalam mendekomposisi bahan organik yang ditunjukkan dengan peningkatan bahan organik, dan hasil terbaik pada kotoran  sapi (B3) dan konsentrasi B. subtilis 15 mL/L masing-masing sebesar 46.47 % dan 34.76 %. Variabel pertumbuhan tidak berbeda nyata kecuali tinggi tanaman dengan pertambahan tinggi paling banyak pada pemberian kotoran kambing sebesar 170.69 %.


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