Presence of Fusarium graminearum sensu stricto associated with triticale (x. Triticosecale Wittmack) in Argentina

Abstract

Triticale is a promising crop resulting for crosses between wheat and rye. This crop has been used as animal feed but also for human food in the preparation of baking products. As regards to triticale diseases, few reports have evaluated the severity of pathogens on this crop. Fusarium Head Blight (FHB) affects several crops including triticale parent crops, with Fusarium graminearum sensu stricto (s.s.) being the most commonly isolated pathogen from plants showing FHB symptoms. The objective of this study was to report the occurrence of F. graminearum s.s. on triticale grains from field samples in Argentina. For this purpose, a total of 40 samples from different crops (barley, rye, triticale, and wheat) showing FHB symptoms were taken during 2017/2018 harvest season. Two Fusarium isolates were identified morphologically as F.graminearum , which were confirmed molecularly by PCR using the specific Fg16 F/R primers pair and by sequencing redand tri101 genes. The sequences obtained were compared with those available in the NCBI database by using BLAST tools showing 99-100% homology with those belonging to F. graminearum s.s.. The potential to produce DON, 15-ADON, and ZEA was determined. Also, the Koch´s postulates were carried out to evaluate the pathogenic capacity of the F. graminearum s.s. isolates in triticale. The results demonstrated that F. graminearum s.s. isolates were pathogenic when triticale spikes were inoculated by spraying under greenhouse conditions. To our knowledge, this is the first time that the presence of F. graminearum s.s. associated with 18 triticale from fields in Argentina was reported.