Fusarium graminearum species complex occurrence on soybean and F. graminearum sensu stricto inoculum maintenance on residues in soybean-wheat rotation under field conditions

PALAZZINI, J. M.; CHULZE, SOFÍA NOEMÍ; CHIOTTA, M.L.; ALBERIONE, E.; ALANIZ ZANON, M. S.; BARROS, G.

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 p. 208 - 216

1364-5072

Aims: The aims of this study were to determine the occurrence of Fusariumgraminearum species complex (FGSC) on soybean pods, seeds and roots,including rhizoplane, during the period of soybean crop in rotation with wheatand to evaluate the FGSC dynamics on wheat and soybean residues during twosoybean growing seasons in rotation with wheat, particularly F. graminearumsensu stricto (FGss).Methods and Results: Soybean roots, pods and seeds were analysed during2012/13 and 2013/14 seasons. The morphological identification of FGSC andmycotoxin analysis was done. Crop residues were taken in both soybean seasonin wheat rotation and FGss were quantificated by real-time PCR. The resultsshowed that Fusarium species, mainly FGSC, survive in a soybean crop inrotation with wheat. Isolation frequency of these species was higher on soybeanpods than on seeds at R6 stage. Deoxynivalenol contamination on soybeanseeds was higher in the 2013/14 season in comparison with the 2012/13 season.Low isolation levels of Fusarium species and species that did not belong toFGSC were observed in soybean root, whereas in rhizoplane a higher level wasobserved. Fusarium species inoculum on residues remained stable during cropsuccession and the FGSC were recovered from both wheat and soybeanresidues. Real time PCR data showed a higher DNA concentration of FGss inwheat residues in the first developmental stages of soybean plants, being thelevels more significant during 2012/13 season. With regard to soybean residuescollected during the wheat growing stages, an increase in DNA from anthesisuntil wheat harvest was observed.Conclusions: In a no-till production system, the populations of FGSC cancolonize wheat and soybean residues to become an inoculum source.Significance and Impact of the Study: This study provides new data on theoccurrence of FGSC populations in soybean plant and FGss on residues insoybean?wheat rotation, a cultural practice commonly used in in Argentina