ACC Deaminase-Positive Halophilic Bacterial Isolates With Multiple Plant Growth-Promoting Traits Improve the Growth and Yield of Chickpea (Cicer arietinum L.) Under Salinity Stress

Abstract

In this study, a total of 50 halophilic bacterial isolates were screened for 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, of these six with the highest ACC deaminase activity were selected for an increase in chickpea yield under salinity. The ACC deaminase activity among the isolates was ranged between 0.12 and 3.56 mM α-KB mg−1 min−1. These six isolates and one reference strain from the Agricultural College, Raichur, were used in the microcosm experiment during the rabi season of 2018. After 60 days of sowing, decreased rhizosphere pH and electrical conductivity (EC) from 8.4 to 7.6 and 4.3 to 3.4 dS m−1, respectively, were reported in chickpea. Among the treatments, Bacillus safensis (B. safensis)-inoculated plants showed a higher number of flowers (71 flowers/plant), pods (49.3 pods/plant), branches (33.3 branches/plant), and enhanced fresh weight (17.2 g/plant) and dry weight (8.1 g/plant). They were corroborated by improved nitrogen and phosphorus absorption of 71.5 and 43.5%, respectively, in B. safensis-treated plants. Based on the microcosm experimental findings, three cultures improving biometric and yield attributes were chosen for the field investigation. The field study was carried out at the Agricultural Research Station, Ganagavathi, during Kharif 2019. The chickpea plants treated with the consortium [B. safensis, Pseudomonas stutzeri, and Staphylococcus xylosus] increased the superoxide dismutase and catalase activity of plants by 258 and 196%, respectively. In addition, an increase in ascorbate peroxidase activity (0.41 μmol of ascorbate oxidized s−1 g−1 fresh weight) in the leaves and proline content was also recorded. The consortium (B. safensis, P. stutzeri, and S. xylosus) significantly increased nutrient uptake (N and P), the number of flowers, number of pods, and yield by 63.26, 39.03, 110, 59.96, and 17.56%, respectively, in chickpeas. Finally, inoculation with a mixture of three isolates is an effective method for increasing chickpea production under osmotic stress.

Exploring the role of mobile genetic elements in shaping plant–bacterial interactions for sustainable agriculture and ecosystem health

“…These include genes impacting plant nutrient acquisition (dos Santos et al, 2020), synthesis of phytohormones (Egamberdieva et al, 2017) and aiding in the suppression of plant pathogens through antagonistic measures (Raaijmakers & Weller, 1998; Trivedi et al, 2021). The gene acdS , encoding the enzyme ACC deaminase, is one such example and has been shown in multiple studies to aid plant growth during various stressful environmental conditions, including salinity and drought stress (Ahmad et al, 2022; Gamalero & Glick, 2022; Glick, 2012; Hontzeas et al, 2005; Nagaraju et al, 2021). Horizontal transfer of acdS has been inferred based on its phylogenetic distribution (Lemaire et al, 2015), but it is not yet clear what range of MGEs may contribute to such movement.…”

Micropropagation of Seed-Derived Clonal Lines of the Endangered Agave marmorata Roezl and Their Compatibility with Endophytes

“…The Table 1 summarizes the plant growth promotion characteristics of the endophyte bacteria used to evaluate their growth stimulation on clonal lines. ACC (ACC deaminase, [ 42 ]), IAA (Indole Acetic Acid, [ 43 ]), N-BRIP (phosphate solubilization, [ 44 ]), NFB (Nitrogen Fixing Bacteria, [ 45 ]).…”

Contribution of Biofertilizers to Pulse Crops: From Single-Strain Inoculants to New Technologies Based on Microbiomes Strategies

“…Regarding salinity stress, chickpea seed inoculation with rhizobium improves mineral uptake, reduces electrolyte leakage, which directly influences photosynthesis, and increases yield attributes in salt-treated plants [ 160 ]. A consortium composed of Bacillus safensis , Pseudomonas stutzeri , and Staphylococcus xylosus increases the total fresh weight of chickpea under salinity stress by 54% in a field experiment, compared to the control under normal conditions [ 161 ].…”