Bacterial consortia inoculation mitigates the water shortage and salt stress in an avocado (Persea americana Mill.) nursery

Abstract

Chile is among the largest avocado producers worldwide; however, currently, its production has diminished mainly attributed to abiotic stresses such as drought and soil salinity. Here, we evaluated the contribution of halotolerant bacterial consortia to water shortage and salt stress tolerance of avocado seedlings (Persea americana Mill.) under field conditions. Inoculation trials were conducted in a commercial nursery to study the effects of two endophytic (C1 and C2) and two rhizosphere (C3 and C4) halotolerant bacterial consortia on growth, biomass, superoxide dismutase (SOD) and thiobarbituric acid reactive substances (TBARS) of avocado seedlings under salt (2% NaCl) stress and water shortage (50% less irrigation). Ours results revealed that avocado inoculation with C4 significantly (P≤0.05) increased aerial and root length; aerial and root fresh weight and chlorophyll content of salt-stressed seedlings; and the aerial length and root fresh weight of seedlings under water shortage. Similarly, the C4 significantly (P≤0.05) increased SOD activity in leaves of both the control and seedlings grown under salt stress and water shortage and also decreased TBARS content in leaves of control plants and of seedlings grown under salt stress. Whereas, C3 increased significantly (P≤0.05) aerial and root length and root fresh weight of salt-stressed seedlings; and also increased the trunk diameter and chlorophyll content of seedlings under water shortage. Similarly, C3 significantly (P≤0.05) stimulated SOD activity of leaves as compared to the control seedlings and also reduced the TBARS content of leaves and roots of avocado seedlings under salt stress. In contrast, the endophytic consortia were less efficient than rhizosphere consortia. Thus, C1 only increased the trunk diameter and chlorophyll content of salt-stressed seedlings and C2 increased the chlorophyll content of avocado seedlings under water shortage. Our study showed the favorable effect of bacterial 3 inoculation on avocado nursey in nursery conditions under water shortage and salt stress, and identified consortia that potentially could be used as avocado biofertilizers.

Modulation of salt tolerance in Thai jasmine rice (Oryza sativa L. cv. KDML105) by Streptomyces venezuelae ATCC 10712 expressing ACC deaminase

“…SBP-6 in wheat 32 , Enterobacter cloacae HSNJ4 in canola 36 , Bacillus subtilis RJ46, Ochrobactrum pseudogrignonense RJ12, and Pseudomonas sp. RJ15 in black gram and pea 37 , and bacterial consortia in avocado 38 increased chlorophyll level more than those of non-inoculated plants, when under salt stress. Moreover, the results were in agreement with other for the ACC deaminase-overexpressing endophytic Pseudomonas spp., which improved photosynthetic performance and water content in tomato 29 .…”

Isolation and Characterization of Cold-Tolerant Hyper-ACC-Degrading Bacteria from the Rhizosphere, Endosphere, and Phyllosphere of Antarctic Vascular Plants

“…Under stressful conditions, plants increase 1-aminocyclopropane-1-carboxylate (ACC) synthesis, increasing ethylene concentrations to inhibit plant development. Interestingly, bacteria able to enzymatically degrade ACC have been shown to promote plant growth under abiotic stresses (such as drought) by lowering ethylene levels through ACC deamination [ 7 , 8 , 9 ]. Therefore, ACC-degrading bacteria have the potential to modulate the ethylene production in plants, which leads to an increase in root elongation and plant biomass production.…”

SiO2‐modified nanocomposite nanofiltration membranes with high flux and acid resistance

“…The permeate flux and the rejection rate were calculated with the following equations: where J is the permeate flux (L/m 2 h), Q is the volumetric quantity of permeate (L), t is the run duration (h), A is the overflow area of the membrane (m), R is the rejection rate (%), and C p and C F (g/L) are the solute concentrations in the permeate solution and feed, respectively. The salt concentrations in the feed and permeate were calculated according to the electrical conductivity of the corresponding salt solution using an electrical conductivity meter (DDS‐11A, Hangzhou Dongxing Instrument Co., Hangzhou, China).…”

“…Water resource shortages have become a serious threat to agricultural, industrial, and urban environments owing to increasingly significant global warming, drought, and pollution . It is predicted that by 2025, two‐thirds of the world's population will face enormous pressure from water shortages, demonstrating the importance of water purification and wastewater treatment.…”