Plants Saline Environment in Perception with Rhizosphere Bacteria Containing 1-Aminocyclopropane-1-Carboxylate Deaminase

Soil salinity stress has become a serious roadblock for food production worldwide since it is one of the key factors affecting agricultural productivity. Salinity and drought are predicted to cause considerable loss of crops. To deal with this difficult situation, a variety of strategies have been developed, including plant breeding, plant genetic engineering, and a wide range of agricultural practices, including the use of plant growth-promoting rhizobacteria (PGPR) and seed biopriming techniques, to improve the plants’ defenses against salinity stress, resulting in higher crop yields to meet future human food demand. In the present review, we updated and discussed the negative effects of salinity stress on plant morphological parameters and physio-biochemical attributes via various mechanisms and the beneficial roles of PGPR with 1-Aminocyclopropane-1-Carboxylate(ACC) deaminase activity as green bio-inoculants in reducing the impact of saline conditions. Furthermore, the applications of ACC deaminase-producing PGPR as a beneficial tool in seed biopriming techniques are updated and explored. This strategy shows promise in boosting quick seed germination, seedling vigor and plant growth uniformity. In addition, the contentious findings of the variation of antioxidants and osmolytes in ACC deaminase-producing PGPR treated plants are examined.

Seed biostimulant Bacillus sp. MGW9 improves the salt tolerance of maize during seed germination

Crop performance is seriously affected by high salt concentrations in soils. To develop improved seed pre-sowing treatment technologies, it is crucial to improve the salt tolerance of seed germination. Here, we isolated and identified the strain Bacillus sp. MGW9 and developed the seed biostimulant MGW9. The effects of seed biopriming with the seed biostimulant MGW9 in maize (Zea mays L.) under saline conditions were studied. The results show that the strain Bacillus sp. MGW9 has characteristics such as salt tolerance, nitrogen fixation, phosphorus dissolution, and indole-3-acetic acid production. Seed biopriming with the seed biostimulant MGW9 enhanced the performance of maize during seed germination under salinity stress, improving the germination energy, germination percentage, shoot/seedling length, primary root length, shoot/seedling fresh weight, shoot/seedling dry weight, root fresh weight and root dry weight. Seed biostimulant MGW9 biopriming also alleviated the salinity damage to maize by improving the relative water content, chlorophyll content, proline content, soluble sugar content, root activity, and activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, while decreasing the malondialdehyde content. In particular, the field seedling emergence of maize seeds in saline-alkali soil can be improved by biopriming with the seed biostimulant MGW9. Therefore, maize seed biopriming with the seed biostimulant MGW9 could be an effective approach to overcoming the inhibitory effects of salinity stress and promoting seed germination and seedling growth.

Management of Wilt Complex of Chickpea with Seed Biopriming and Soil Application of Trichoderma spp.

Background: Chickpea wilt complex caused by several soil-borne pathogens is a serious biotic constraint for chickpea production.Methods: To find out the effective management of the disease through seed biopriming and soil application of biocontrol agents under in vivo and in vitro conditions experiments were carried out during rabi 2018-19 and 2019-20 at Anand Agricultural University, Anand, Gujarat.Result: Seed biopriming showed a positive impact producing vigorous plant shoot and root system, besides disease control during in vitro conditions. While under in vivo conditions, the pooled results of two years revealed that seed biopriming for 10 h with the suspension of talc-based formulation (2 x 108 CFU/g) of Trichoderma viride or T. asperellum @ 50 g in 250 ml of water/kg of seed followed by soil application of T. viride or T. asperellum enriched FYM (10g/kg FYM) @ 100 g/m2 of soil found significant for the disease management as well as higher yield. The seed biopriming alone control the disease in the range of 23-34% and increased the yield of chickpea by 23-29%. However, combined applications of seed biopriming as well as soil application significantly control the disease in the range of 51-70% and increased the grain yield by 41-51% over untreated control.

Roles of Plant Growth-Promoting Rhizobacteria (PGPR) in Stimulating Salinity Stress Defense in Plants: A Review

To date, soil salinity becomes a huge obstacle for food production worldwide since salt stress is one of the major factors limiting agricultural productivity. It is estimated that a significant loss of crops (20–50%) would be due to drought and salinity. To embark upon this harsh situation, numerous strategies such as plant breeding, plant genetic engineering, and a large variety of agricultural practices including the applications of plant growth-promoting rhizobacteria (PGPR) and seed biopriming technique have been developed to improve plant defense system against salt stress, resulting in higher crop yields to meet human’s increasing food demand in the future. In the present review, we update and discuss the advantageous roles of beneficial PGPR as green bioinoculants in mitigating the burden of high saline conditions on morphological parameters and on physio-biochemical attributes of plant crops via diverse mechanisms. In addition, the applications of PGPR as a useful tool in seed biopriming technique are also updated and discussed since this approach exhibits promising potentials in improving seed vigor, rapid seed germination, and seedling growth uniformity. Furthermore, the controversial findings regarding the fluctuation of antioxidants and osmolytes in PGPR-treated plants are also pointed out and discussed.

Seed Biostimulant MGW9 (SB-MGW9) Biopriming Improves Salt Tolerance during Maize Seed Germination

Crop performance is seriously affected by high salt concentrations in soils. To develop more new seed pre-sowing treatment technologies it is crucial to improve the salt tolerance of seed germination. Here we isolated and identified the strain Bacillus sp. MGW9 and developed the seed biostimulant MGW9 (SB-MGW9) by the strain. Effect of seed biopriming with SB-MGW9 in maize (Zea mays L.) under saline condition were studied. The results showed that the Bacillus sp. MGW9 has the characteristics of salt tolerance, nitrogen fixation, phosphorus dissolution, indole-3-acetic acid production and the like. Seed biopriming with SB-MGW9 enhanced the performance of maize during seed germination under salinity stress to improve the germination energy, germination percentage, shoot/seedling length, primary root length, shoot/seedling fresh weight, shoot/seedling dry weight, root fresh weight and root dry weight. SB-MGW9 biopriming also alleviates the salinity damage to maize by improving relative water content, chlorophyll content, proline content, soluble sugar content, root activity, activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, decreasing the malondialdehyde content. Especially, the field seedling emergence of maize seeds in saline-alkali soil can be improved by SB-MGW9 biopriming. Therefore, maize seed biopriming with SB-MGW9 can be an effective approach to resist the inhibitory effects of salinity stress and promote seed germination and seedling growth.

Roles of Plant Growth-Promoting Rhizobacteria (PGPR) in Stimulating Salinity Stress Defense in Plants: A Review

To date, soil salinity becomes a huge obstacle for food production worldwide since salt stress in plants is one of the major factors limiting agricultural productivity. It is estimated that a significant loss of crops (20%–50%) would be due to drought and salinity. To embark upon this harsh situation, numerous strategies such as plant breeding, plant genetic engineering, and a large variety of agricultural practices including the applications of plant growth-promoting rhizobacteria (PGPR) and seed biopriming technique have been developed to improve plant defense system against salt stress, resulting in higher crop yields to meet human’s increasing food demand in the future. In the present review, we update and discuss the advantageous roles of beneficial PGPR as green bioinoculants in mitigating the burden of high saline conditions on morphological parameters and on physio-biochemical attributes of plant crops via diverse mechanisms. In addition, the applications of PGPR as a useful tool in seed biopriming technique are also updated and discussed since this approach exhibits promising potentials in improving seed vigor, rapid seed germination, and seedling growth uniformity, Furthermore, the controversial findings regarding the fluctuation of antioxidants and osmolytes in PGPR-treated plants are also pointed out and discussed.