Diversity and mycotoxin production by Fusarium temperatum and Fusarium subglutinans as causal agents of pre-harvest Fusarium maize ear rot in Poland

Ł Stępień,K Gromadzka,J Lalak-Kańczugowska,J Chełkowski,A Basińska-Barczak

doi:10.1007/s13353-018-0478-x

Abstract

Maize ear rot is a common disease found worldwide, caused by several toxigenic Fusarium species. Maize ears and kernels infected by Fusarium subglutinans contained significant amounts of beauvericin, fusaproliferin, moniliformin, and enniatins. In 2011, F. subglutinans sensu lato has been divided into two species: Fusarium temperatum sp. nov. and F. subglutinans sensu stricto, showing different phylogeny and beauvericin production within the populations of maize pathogens in Belgium. Isolates of the new species—F. temperatum—were also identified and characterized in Spain, Argentina, Poland, France, and China as one of the most important pathogens of maize. Moreover, F. temperatum was proved to be pathogenic to maize seedlings and stalks. We identified Fusarium isolates obtained from diseased maize ears collected between 2013 and 2016 in Poland (321 isolates). Based on morphological analyses, six Fusarium species were identified. Molecular identification performed on the set of selected isolates (42 isolates) revealed 34 isolates to be F. temperatum and only five to be F. subglutinans. Interestingly, the phylogenetic analysis showed that the population of F. temperatum infecting maize in Poland remained quite uniform for over 30 years with only a few exceptions. For the first time, a single isolate of Fusarium ramigenum was detected from the area of Poland. Significant amounts of BEA were found in Fusarium-damaged kernels. The same kernel samples contained also enniatins A1, A, B1, and B. The results clearly demonstrate the occurrence of F. temperatum as maize pathogen in Poland for over the last three decades.

Highlights

Maize ear rot is a common disease found worldwide, caused by several toxigenic Fusarium species and leading to the accumulation of several mycotoxins in kernels
Maize ears and kernels infected by Fusarium subglutinans contained significant amounts of beauvericin, fusaproliferin, moniliformin, and enniatins
Maize ears and kernels infected by F. subglutinans contained significant amounts of beauvericin (BEA), fusaproliferin (FP), moniliformin (MON), and enniatins (ENNs) (Logrieco et al 1998; Gromadzka et al 2016)

Summary

Introduction

Maize ear rot is a common disease found worldwide, caused by several toxigenic Fusarium species and leading to the accumulation of several mycotoxins in kernels. The research on toxigenic fungal species and mycotoxins contaminating maize kernels has been conducted in Poland since 1984 in 15 growing seasons. Since 1995, the frequency of Fusarium verticillioides increased in most years, and this species outcompeted F. subglutinans, which frequency decreased, in 1993 and 2006 seasons (Gromadzka et al 2016). Mycotoxin moniliformin was the first toxin identified in the cultures of F. subglutinans isolates and in infected maize kernels from Poland (Sharman et al 1991; Lew et al 1996). Maize ears and kernels infected by F. subglutinans contained significant amounts of beauvericin (BEA), fusaproliferin (FP), moniliformin (MON), and enniatins (ENNs) (Logrieco et al 1998; Gromadzka et al 2016).

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