Presentation Title

Analysis of the synergistic effects of mixed populations of rhizobial soil bacteria on host plant roots, infection, and the development of nodules

Start Date

November 2016

End Date

November 2016

Location

HUB 302-175

Type of Presentation

Poster

Abstract

Legume plants form mutualistic relationships with various rhizobacteria in the soil, which promote plant growth by improving nutrient acquisition, modulating plant hormone levels, and protecting the plant from biotic and abiotic stress. The rhizobacteria Sinorhizobium meliloti and Bacillus simplex are known to have symbiotic relationships with white sweet clover, Melilotus alba. S. meliloti induces the formation of root nodules, where the bacteria reside and fix atmospheric nitrogen into ammonia, a form of nitrogen plants can effectively use. Nitrogen is the most limited macronutrient in soil but is essential for plant development. B. simplex enhances plant growth and survival under stressful conditions. Studies have shown that plants co-inoculated with S. meliloti and B. simplex exhibit better growth, including more mass, greener color, and taller height. This research project examined whether B. simplex enhanced infection and nodulation by S. meliloti and its pilA mutants. The pilA genes encode Type IV pili; mutation of these genes delays root infection. An experiment was conducted in which M. alba was inoculated with combinations of the two rhizobacteria. Half of the M. alba plants were inoculated with S. meliloti and the other half were co-inoculated with S. meliloti and B. simplex. Plant growth was observed and dry weights of shoots and roots were measured with a scale. Roots were GUS stained and observed using microscopy to visualize the location of the bacteria, infection process, and nodulation. The results supported previous research and indicated that co-inoculation with S. meliloti and B. simplex yielded more robust plant growth than a single inoculation of S. meliloti.

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Analysis of the synergistic effects of mixed populations of rhizobial soil bacteria on host plant roots, infection, and the development of nodules

HUB 302-175

Legume plants form mutualistic relationships with various rhizobacteria in the soil, which promote plant growth by improving nutrient acquisition, modulating plant hormone levels, and protecting the plant from biotic and abiotic stress. The rhizobacteria Sinorhizobium meliloti and Bacillus simplex are known to have symbiotic relationships with white sweet clover, Melilotus alba. S. meliloti induces the formation of root nodules, where the bacteria reside and fix atmospheric nitrogen into ammonia, a form of nitrogen plants can effectively use. Nitrogen is the most limited macronutrient in soil but is essential for plant development. B. simplex enhances plant growth and survival under stressful conditions. Studies have shown that plants co-inoculated with S. meliloti and B. simplex exhibit better growth, including more mass, greener color, and taller height. This research project examined whether B. simplex enhanced infection and nodulation by S. meliloti and its pilA mutants. The pilA genes encode Type IV pili; mutation of these genes delays root infection. An experiment was conducted in which M. alba was inoculated with combinations of the two rhizobacteria. Half of the M. alba plants were inoculated with S. meliloti and the other half were co-inoculated with S. meliloti and B. simplex. Plant growth was observed and dry weights of shoots and roots were measured with a scale. Roots were GUS stained and observed using microscopy to visualize the location of the bacteria, infection process, and nodulation. The results supported previous research and indicated that co-inoculation with S. meliloti and B. simplex yielded more robust plant growth than a single inoculation of S. meliloti.