Presenter: Katie Webb
Authors: Katherine Webb
Faculty Advisor: Amita Kaundal
Institution: Utah State University
Plant-microbe relations are integral to plant survival and crop productivity. Part of a plant’s biosphere are endophytes, microbes found between the cells of a plant. Endophytes can be beneficial to help a plant cope with abiotic stressors such as salinity. In Utah, our soils are high in salinity due to topography and climate. Climate change has increased soil salinity worldwide, and increased incidences of drought are forcing the use of more saline water for irrigation. Thus, salt is a concern for farmers. In this study, we identified halotolerant bacteria from the roots and nodules ofCeanothus velutinus, a native plant of the Intermountain West region of the United States which thrives in semi-arid and harsh conditions. Roots and nodules were crushed and screened for bacterial growth on nutrient agar with 2%, 4%, 6%, 8%, and 10% NaCl. 49 halotolerant colonies were isolated from the endosphere using the streak plate method and identified by 16s rRNA sequencing. Literature review revealed that many of the halotolerant isolates are known Plant-Growth Promoting Bacteria, or PGPB. This includes members from the genusStreptomycetes, Pseudomonas, Anterobacter,andBacillus. In our testing, 14% of the isolates were found to fix nitrogen, 24% solubilize phosphate, 51% produce siderophore, and 24% produce indole-3-acetic acid (>5 ⲙg/mL). We selected endophytes which had positive results for one or more of these traits, and are currently testing their effects on the growth of model plantArabidopsis thaliana,Zea mays(maize), andMedicago sativa(alfalfa), under control and saline conditions in the greenhouse. Growth characteristics such as biomass, stomatal conductance, net photosynthetic rate, relative water content, and electrolyte leakage will be measured and compared. Identification of plant growth benefiting halotolerant endophytes can lead to the development of biofertilizers for saline soils, and be utilized as a tool in sustainable, productive crop production in future farming.