Christina Koo

Document Type

Honors Thesis


Bradyrhizobium japonicum is a nitrogen-fixing bacterium which forms a symbiotic relationship with leguminous soybean plants, converting atmospheric nitrogen into ammonia. The process of nodulation involves signaling components from the plant and activation of genes promote nodule formation. Soybean lectin’s current function in plants are unknown and may be a crucial component in nodulation. In previous studies, the copper tolerance protein, bll2211 (copB) was differentially expressed when exposed to soybean lectin. In this study, the role of environmental copper exposure was investigated to understand the role of soybean lectin in growth and nodulation of B. japonicum. We examined this by construction of a growth curve and performing a pouch experiment at various concentrations of copper for B. japonicum and its mutant ∆copB. Overall, there was less growth, nodule formation, and nitrogen-fixation in ∆copB. Thus, soybean lectin and copB may play a role in nodulation between B. japonicum and soybean plants.

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