Symptom development in soybeans infected with Soybean dwarf luteovirus is tied to differential activation of the salicylic or jasmonic acid defense signaling pathways.
W. SCHNEIDER (1), C. Dardick (2), O. Smith (3), M. Graham (4), D. Luster (1) (1) USDA-ARS FDWSRU, U.S.A.; (2) USDA-ARS AFRC, U.S.A.; (3) Hood College, U.S.A.; (4) USDA-ARS CICGR, U.S.A.

Two common strains of the phloem limited soybean dwarf luteovirus (SbDV) are known to cause strikingly distinct symptoms. SbDV-D strains (dwarfing) are often associated with severe plant stunting, leaf greening, and curled leaves. SbDV-Y strains (yellowing) do not cause stunting but instead confer a pronounced yellowing of leaves and wavy leaf margins. SbDV-D and SbDV-Y are closely related (85-92% sequence identity), and the reasons for the distinct symptom development are currently unknown. Host gene expression in SbDV-D and SbDV-Y infected soybean was assessed for leaves showing typical dwarfing or yellowing symptoms. Results showed that SbDV-D strain infected plants displayed a marked induction of salicylic acid (SA) dependent defense responses including up-regulation of numerous pathogenesis-related (PR) genes. SbDV-Y strain leaves showed evidence of jasmonic acid (JA)-mediated defense signaling that included a number of known JA biosynthesis and marker genes. Free SA levels in SbDV-D strain infected leaves were found to be 10 fold higher than in SbDV-Y strain infected leaves or healthy controls. Collectively, the data suggests that the distinct symptomologies associated with the closely related SbDV-D and SbDV-Y strains may be induced by differential activation of SA and JA defense signaling pathways.

Abstract Number: P9-300
Session Type: Poster