Amelioration of salt stress in chickpea (Cicer arietinum L.) by coinculation of ACC deaminase-containing rhizospheric bacteria with Mesorhizobium strains

Abstract

Chickpea is a major legume crop grown in the semi-arid tropics and its yields are adversely affected by salinity. In this study, 55 rhizobacterial isolates obtained from the chickpea rhizosphere soil were screened for their salt tolerance. At 3% NaCl concentration, 41.8% rhizobacterial isolates formed colonies varying from 0.5-10 mm size and only 10.9 per cent isolates showed growth at 4% NaCl concentration. Significant growth on ACC supplemented medium plates was observed in 32.7% rhizobacterial isolates. Coinoculation studies with ACC + as well as ACC -Mesorhizobium and rhizobacterial isolates were made on chickpea under chillum jar conditions containing sloger's broth with salt (EC, 4dS/m) and without salt. Coinoculation of Mesorhizobium isolate MBD26 (ACC + ) and rhizobacterial isolate RHD18 (ACC + ) formed 59 nodules/plant and caused 112.9% increase in plant dry weight as compared to uninoculated control plants at 50 days of plant growth, whereas in the presence of salt, only 31.2% increase in plant dry weight was observed in comparison to uninoculated plants. At 80 days of plant growth, coinoculation of Mesorhizobium isolate MBD26 (ACC + ) with rhizobacterial isolate RHD18 (ACC + ) further increased the nodule number (78 nodules/plant) and 141.9% increase in shoot dry weight was observed as compared to uninoculated plants. Thus, it was concluded that coinoculation of ACC + Mesorhizobium and rhizobacterial isolates showed more stimulatory effect on nodulation and plant biomass under normal and salt amended treatments.

Exogenous ACC Deaminase Is Key to Improving the Performance of Pasture Legume-Rhizobial Symbioses in the Presence of a High Manganese Concentration

“…Nevertheless, in both cases, the presence of the Q1 strain facilitated the formation of nodules by these rhizobial strains and led to an increase of the host's growth. These results are in agreement with previous reports showing that non-rhizobial bacteria stimulated legume growth and nodulation under different abiotic stress conditions, such as salinity [18,48,[53][54][55][56][57], toxicity of copper [58][59][60], Mn [18], cadmium [23,61], and zinc [60]; as well as under biotic stress, namely root rot caused by Fusarium solani [56]. On the other hand, no beneficial effects of the co-inoculation of non-rhizobial bacterium along with M. ciceri LMS-1 were observed with the chickpea plants grown either under non-stressed or stressed conditions.…”

“…Similar results were reported with Pisum sativum [45], Lotus spp. [20], Lens culinaris [45,46], Vigna radiata [47], chickpea [48], and soybean [49,50] plants when co-inoculated with plant growth-promoting bacteria and with their rhizobia microsymbionts.…”

The influence of plant growth-promoting rhizobacteria in plant tolerance to abiotic stress: a survival strategy

“…Chickpea plant affected by an increase in salinity was rescued by co-inoculation with two deaminase enzyme-producing microbes ( Mesorhizobium MBD26 and Rhizobacteria RHD 18) with an observed nodulation capacity of 49 nodules per plant, 201 mg weight of nodules, 12.28 mg per plant nitrogen, and a rise in 31.2% of the above the soil plant part dry weight (shoot dry weight). The result was further increased to 53 nodules and 116.9% grain produced, with N 2 level spanning between 9.59 and 27.36 mg per plant investigated (Chaudhary and Sindhu 2017 ).…”

Growth Inhibition of Pathogenic Fungi and Salt Tolerance Ability of Rhizosphere Bacteria

“…Selected rhizobacterial isolates were analyzed for their ability to grow at different concentrations of NaCl i.e., 0, 2, 4, 6 and 8% (w/v) on LB medium plates (Chaudhary and Sindhu, 2017). Salt amended medium plates were spotted with a 20 µl growth suspension of different bacterial isolates and incubated for 3-4 days at 28±2ºC in a BOD incubator.…”

“…After exposure to salt stress for 20 days, SQR9 significantly promoted the growth of maize seedlings under salt stress and enhanced the chlorophyll content of the plants as compared with the control. Chaudhary and Sindhu (2017) obtained 55 rhizobacterial isolates from the chickpea rhizosphere soil and 41.8% rhizobacterial isolates formed colonies varying from 0.5-10 mm size at 3% NaCl concentration, and only 10.9% isolates showed growth at 4% NaCl concentration.…”