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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #76065
Title: HYPERNODULATION OF SOYBEAN, MUNG BEAN, AND HYACINTH BEAN IS CONTROLLED BY A COMMON SHOOT SIGNAL

Author
item Harper, James
item CORRIGAN, KAREN - U OF ILLINOIS, URBANA
item BARBERA, ANTONIO - INST AGR, CATANIA, ITALY
item ABD-ALLA, MOHAMMED - ASSIUT U, ASSIUT, EGYPT

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Formation of nodules (specialized structures on roots) on legume species is important to agriculture in that they provide nitrogen to the plant through a process termed symbiotic nitrogen fixation. Understanding control of the degree of nodulation is important to scientists and agriculturist who want to enhance symbiotic nitrogen fixation. This study showed that control of nodule numbers on three legume species (soybean, mung bean, and hyacinth bean) is mediated by a common signal that is translocated from the shoot to the root. This finding will provide renewed interest in identifying this signal compound since one could potentially control the amount of symbiotic nitrogen fixation across a number of legume species if the signal can be identified. These results are important to scientists who are seeking to alter symbiotic nitrogen fixation, and ultimately may impact agricultural producers who are using legumes in crop rotations to minimize the amount of fertilizer nitrogen being applied.

Technical Abstract: Interspecie grafts between soybean [Glycine max (L.) Merr] and mung bean (Vigna radiata L.), or soybean and hyacinth bean (Lablab purpureus L.), were made to evaluate whether a common translocatable signal controls expression of hypernodulation among legume species. Grafting of a NOD1-3 (hypernodulating soybean) shoot to roots of either mung bean or hyacinth bean resulted in greater nodule numbers than for self-grafted mung bean, self-grafted hyacinth bean, or when a Williams 82 (normally nodulating soybean) shoot was grafted to mung bean or hyacinth bean roots. Symbiotic N2 fixation by nodulated mung bean roots was enhanced when grafted to either Williams 82 or NOD1-3 soybean shoots, compared with self grafted mung bean plants. Grafting soybean shoots to hyacinth bean roots positively affected symbiotic N2 fixation, but the magnitude was less than observed when mung bean roots were grafted to soybean shoots. Seed were obtained from reciprocal grafts between soybean and mung bean to test for bacterial specificity for infection and nodule development. Seedling progeny from the reciprocal mung bean/soybean grafts were not altered in terms of bacterial specificity for nodulation. It was concluded that control of hypernodulation expression by a shoot-transmissible factor is common among soybean, mung bean, and hyacinth bean.