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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #142051
Title: THE P34 SYRINGOLIDE ELICITOR RECEPTOR INTERACTS WITH A SOYBEAN PHOTORESPIRATION ENZYME, NADH-DEPENDENT HYDROXYPYRUVATE REDUCTASE

Author
item OKINAKA, YAUSHI - UNIV OF CALIFORNIA
item YANG, CHING-HONG - UNIV OF CALIFORNIA
item Herman, Eliot
item KINNEY, ANTHONY - DUPONT EXPERIMENTAL STA.
item KEEN, NOEL - UNIV OF CALIFORNIA

Submitted to: Molecular Plant Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2002
Publication Date: 12/1/2002
Citation: OKINAKA, Y., YANG, C., HERMAN, E.M., KINNEY, A., KEEN, N.T. THE P34 SYRINGOLIDE ELICITOR RECEPTOR INTERACTS WITH A SOYBEAN PHOTORESPIRATION ENZYME, NADH-DEPENDENT HYDROXYPYRUVATE REDUCTASE. MOLECULAR PLANT MICROBE INTERACTIONS. 2002. v. 15. p. 1213-1218.

Interpretive Summary: The dominant allergen of soybean seeds is a protein named P34. Although this protein is important to producers and consumers because of its allergenic properties, the function of this protein in the soybean seed and plant has remained unknown. Elucidating the function of the P34 protein is important because soybeans have been engineered to remove the allergen and it is essential to determine whether removing the protein will introduce any problems that would limit the use of this variety for farm production. Previous results have indicated that P34 may have a role in the resistance to a bacterial disease. The results presented in this paper expand on those initial observations to now show how the P34 protein is connected with other soybean proteins that may confer a bacterial defense mechanism. The results of this paper will be of primary interest to plant pathologists, but its implications extend far beyond that because the lines that have been developed to be nonallergenic are being tested in the field. These results indicate that critical tests need be conducted to ensure that the nonallergenic soybean plants are not susceptible to infection by plant bacterial diseases. This information is a critical to soybean producers and an essential step in the development of genetically modified plants to ensure high productivity.

Technical Abstract: The syringolide receptor P34 mediates avrD-Rpg4 gene-for-gene complimentarity in soybean. However, the mechanism underlying P34 signal transmission after syringolide binding is unknown. In an effort to identify a second messenger for P34, soybean leaf proteins were run though a P34-affinity column. A 42 kDa protein which specifically bound to the column was identified as an NADH-dependent hydroxypyruvate reductase (HPR) by N-terminal peptide sequencing. Hydroxypyruvate reductase is an important enzyme involved in the plant photorespiration system. Screening of a soybean cDNA library yielded two distinct HPR clones that encoded proteins with 97% identity (P42-1 and P42-2). Surprisingly, only P42-2 displayed good binding with P34 in a yeast two-hybrid assay, indicating that P42-2, but not P42-1, is a potential second messenger for P34. Glycerate and its analogs, which are utilized in the photorespiration system, were tested for their inhibitory effect on syringolide-induced host response (HR) to evaluate the biological significance of P42-2. Interestingly, the downstream products of HPR (glycerate and 3-phosphoglycerate) inhibited HR, but the upstream analogs (hydroxypyruvate or serine) did not have a significant effect on HR. These results suggest that P42-2 is a primary target for a P34/syringolide complex and P42-2 binding with the complex probably induces HR by inhibiting an HPR function(s) in soybean leaves.