PhD Scholar Brigham Young University, Provo, Utah Provo, Utah
Body of Abstract: A major problem facing agriculture is increasing salinity in agricultural land due to drought and irrigation water that contains high levels of salts, which inhibit plant growth and development. Plant biologists are exploring different approaches to develop salt-tolerant crops. Salt-tolerant plants (halophytes) have evolved to grow in saline soils with 200 mM NaCl and some can tolerate ~600 mM NaCl. The potential of salt-tolerant plant growth promoting rhizobacteria (PGPR) to stimulate plant growth in poor quality soil is a potential solution. Some halophilic microbes produce plant growth hormones such as IAA or ABA that directly promote photosynthesis and plant growth. Some halotolerant bacteria also produce siderophores or solubilize phosphate that allow plants to take up iron and convert phosphate into biologically available forms.
The aim of my study is to isolate culturable halophilic bacterial species from the roots (endophytes or rhizosphere) of native halophytes and study the effect of selected strains on alfalfa in growth stimulation trials and determine properties of selected isolates that contribute to changes in host plant growth response under saline conditions. Also, to identify changes in host plant gene expression in response to halophilic bacterial inoculation under salt treatment. For this purpose, bacterial strains were characterized for PGP traits (P-activity, IAA, Zn-solubilization). Potential halophilic strains were selected and evaluated in a growth room (in vivo) trial with alfalfa. Re-isolated colonies of halophilic bacteria from alfalfa were confirmed by viable cell count and PCR. The results demonstrated that application of halophilic bacteria has the potential to enhance plant growth and nutrient uptake efficiency in saline conditions as compared with controls. The results from this project will benefit large-scale and small-scale farmers worldwide who live in areas affected by salinity.