Microbial Inoculants for the Improvement of Alfalfa Crop Productivity and Health

View the project final report

Commodities

Practices

• Crop Production: biological inoculants
• Pest Management: biological control
• Soil Management: soil microbiology

Alfalfa is the third largest field crop in the US, with hay value calculated at over $9.9 billion last year. Alfalfa is susceptible to fungal pathogens and drought, which are increasing threats as climate patterns become more extreme and unpredictable. The purpose of this work will be to determine enhanced protective activities of the plant growth promoting rhizobacteria (PGPR) Bacillus subtilis UD1022 (‘UD1022’) and the legume symbiont Sinorhizobium meliloti applied to alfalfa. Legumes such as alfalfa are already routinely treated with beneficial plant bacteria Rhizobia, which fixes nitrogen from the atmosphere, reducing nitrogen inputs and increasing sustainability. UD1022 has been shown to promote plant growth and resistance by increasing biomass, inhibiting fungal pathogens and conferring drought tolerance to many different types of plants. Importantly, UD1022 has been shown to act synergistically with Rhizobia by enhancing biomass and increasing lateral root numbers in pea plants inoculated along with their specific symbiotic bacteria. We will be performing a series of experiments to test the benefits of the plant beneficial bacteria Bacillus subtills UD1022 on alfalfa treated with its symbiotic bacteria Sinorhizobium meliloti. We will define UD1022 antagonistic effect on alfalfa specific fungal pathogens, and the combined bacteria’s ability to suppress fungal infections in alfalfa. We will also be determining the potential enhanced effect of co-inoculation on alfalfa biomass and drought tolerance. Plant microbial inoculants represent an ‘all-in-one’ solution which can increase crop biomass, suppress fungal pathogens and increase legume drought resistance, simultaneously benefiting farmers and the environment.

1. Determine direct fungal inhibition of UD1022 on six fungal pathogens of alfalfa using standard laboratory assays.

2. Test alfalfa resistance to three select alfalfa fungal pathogens when inoculated with both S. meliloti and UD1022 compared to un-inoculated and S. meliloti alone.

3. Evaluate whether inoculation with UD1022 and S. meliloti increases overall drought resistance and drought recovery in a greenhouse setting.

4. Quantify alfalfa biomass, lateral root number and number of symbiotic root nodules of plants inoculated with S. meliloti, both S. meliloti and UD1022 and no inoculation in a greenhouse setting.

5. Compare the biomass and nitrogen content of alfalfa treated with S. meliloti alone or both S. meliloti and UD1022 in the field.