Metabolic profiles of soybean roots during early stages of Fusarium tucumaniae infection

Authors: SCANDIANI, MARIA - National University Of Rosario; LUQUE, ALICIA - National University Of Rosario; RAZORI, MARIA - National University Of Rosario; CIANCIO CASALINI, LUCILA - National University Of Rosario; AOKI, TAKAYUKI - National Institute Of Agrobiological Sciences (NIAS); O Donnell, Kerry; CERVIGNI, GERARDO D. - National University Of Rosario; SPAMPINATO, CLAUDIA - National University Of Rosario

Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2014
Publication Date: 10/21/2015
Publication URL: http://handle.nal.usda.gov/10113/62957
Citation: Scandiani, M.M., Luque, A.G., Razori, M.V., Ciancio Casalini, L., Aoki, T., O'Donnell, K., Cervigni, G.L., Spampinato, C.P. 2015. Metabolic profiles of soybean roots during early stages of Fusarium tucumaniae infection. Journal of Experimental Botany. DOI:10.1093/jxb/eru432.

Interpretive Summary: Fusarium tucumaniae is the main causal agent of sudden death syndrome (SDS) of soybean in Argentina. Although infections caused by this filamentous fungus are largely confined to the roots, this pathogen can induce a systematic response, resulting in dramatic disease symptoms in the leaves of susceptible cultivars. Because soybean cultivars exhibit varying levels of resistance to this economically destructive phytopathogen, a rapid and accurate method for scoring disease is essential for plant breeders to efficiently screen soybean cultivars for resistance to SDS. In this research, we characterized the spectrum of chemicals produced in the roots of a susceptible and a partially resistance soybean cultivar in response to infection by a pathogenic isolate of F. tucumaniae. Infected plant roots were analyzed chemically at 7, 10, 14 and 25 days post-inoculation, using a gas chromatographic-mass spectrometric (GC-MS) method. These analyses revealed that the chemical profiles of the susceptible and partially resistance cultivar roots were clearly distinguishable at the earliest time points. In contrast to the partially resistant cultivar, susceptible plant roots accumulated high levels of several chemicals (i.e., amino acids and cadaverine), which suggests that this method can be used by plant breeders to screen soybean cultivars for resistance to SDS. Results of this study will be of interest to plant breeders, pathologists, physiologists, natural product chemists and seed producers.

Technical Abstract: Soybean germplasm exhibits various levels of resistance to Fusarium tucumaniae, the main causal agent of sudden death syndrome (SDS) of soybean in Argentina. In this study, two soybean genotypes, one susceptible (NA 4613) and one partially resistant (DM 4670) to SDS infection, were inoculated with F. tucumaniae. Disease symptoms were scored at 7, 10, 14, and 25 days post-inoculation (dpi). The greatest difference in the area under the disease progress curve (AUDPC) values among genotypes was observed at 25 dpi. In order to detect early metabolic markers that could potentially discriminate between susceptible and resistant genotypes, gas chromatography–mass spectrometry (GCMS) analyses of root samples were performed. These analyses show higher levels of several amino acids and the polyamine cadaverine in the inoculated than in the uninoculated susceptible cultivar at 7 dpi. Principal component analysis (PCA) revealed that the metabolic profile of roots harvested at the earliest time points from the inoculated susceptible genotype was clearly differentiated from the rest of the samples. Furthermore, variables associated with the first principal component were mainly amino acids. Taken together, the results indicate that the pathogen induced the susceptible plant to accumulate amino acids in roots at early time points after infection, suggesting that GC-MSbased metabolomics could be used for the rapid characterization of cultivar response to SDS.