Competitive interactions between Microdochium nivale var. majus, M. nivale var. nivale and Fusarium culmorum in planta and in vitro

Abstract

Microdochium nivale var. majus and var. nivale are economically important fungal pathogens of cereal seedlings, stem bases and ears, as is the toxigenic species Fusarium culmorum. Competition experiments on seedlings support an earlier report of differential host preference between the varieties of M. nivale on wheat and rye seedlings at 15 degrees C, but showed that it does not extend across a broad range of temperatures. The studies showed that, although interaction is disadvantageous to the less virulent pathogen, it does not confer an advantage to the more virulent pathogen. In mixed inoculum experiments on wheat seedlings at 15 degrees C and 20 degrees C, F. culmorum suppressed the growth of both varieties of M. nivale. However, if M. nivale var. majus became established on the seedlings, it was able to co-suppress colonization of wheat seedlings by F. culmorum. In contrast M. nivale var. nivale did not suppress F. culmorum significantly. The growth of M. nivale var. majus and F. culmorum was also co-suppressed in liquid culture. Significantly, the accumulation of deoxynivalenol mycotoxin was also reduced in the mixed in vitro culture compared with axenic culture of F. culmorum. However, in vitro interaction studies on solidified media were of only limited use in predicting the outcome of competitions in planta.

Early PCR-based detection of Fusarium culmorum, F. graminearum, F. sporotrichioides and F. poae on stem bases of winter wheat throughout Poland

“…Negative correlation has also been found between F. moniliforme and (n=61) both F. graminearum and F. subglutinans (Reid et al 1999). In addition, F. culmorum was showed to suppress the growth of M. nivale (Simpson et al 2004) and F. graminearum reduced the growth rate of F. moniliforme and F. proliferatum (Marin et al 1998). These relationships are likely to be explained by the influence of other associated factors, i.e., forecrop and date of sowing that emerged from further analyses of samples.…”

Interactions between Head Blight Pathogens: Consequences for Disease Development and Toxin Production in Wheat Spikes

“…Note, however, that competition was evaluated here in wheat heads but certainly takes place in other environments (e.g., crop debris), where the interactions and role of toxins may be different. In vitro studies (3,12) Table 1) in single inoculations (SI) or in coinoculation. Treatments indicated by the same lowercase letter within the same graph were not significantly different; the six coinoculation treatments (fg178/fc337, fg178/fc337, fg178/fp3, fg91/fc337, fg91/fc337, and fg91/fp3) are presented twice in order to compare each of them with the two single inoculations (fg178 and fg91).…”

“…Most studies on interactions among Fusarium species were carried out under in vitro conditions (3,4) and do not allow drawing a clear conclusion. Only a few ones were done in planta, but most often on seedlings.…”

Mutual Exclusion between Fungal Species of the Fusarium Head Blight Complex in a Wheat Spike

“…Most studies on the direct interaction between Fusarium species have been done on laboratory media, but in vitro interaction studies are of limited use in predicting the outcome of fungal species competition in planta (7,8). In the few available in vivo studies, interactions among Fusarium species have been identified as competitive in most cases.…”

“…In the few available in vivo studies, interactions among Fusarium species have been identified as competitive in most cases. Simpson et al (7) studied interspecific interactions between F. culmorum and the two Microdochium species on wheat seedlings and in vitro. They showed that F. culmorum was a better competitor and inhibited colonization by Microdochium spp.…”