3.3.71
USE OF TOTAL PROTEIN PROFILES TO DISTINGUISH MONILINIA SPECIES

A BELISARIO, L CORAZZA and L LUONGO

ISPV, 00156 Roma, Italy

Background and objectives
Monilinia spp. are related to brown rot of stone and pome fruit. Of the three species, M. laxa and M. fructigena occur in Europe, whilst M. fructicola occurs in North and South America, South Africa, Australasia and Japan, and it is an EU quarantine listed pathogen. The current classification system in Monilinia relies mainly on cultural and morphological characteristics. Morphological plasticity and overlap of phenotype among species make identification difficult [1]; for this reason a cultural protocol was set-up [2]. Furthermore a means of identification based on total mycelial protein electrophoresis for the detection of the three species was investigated.

Materials and methods
Ten isolates per Monilinia species, collected from various countries, were investigated. They were grown in potato-dextrose broth, filtrated, and freeze-dried. Lyophilized mycelia were ground to a fine powder and proteins were extracted. Sodium dodecyl sulfate polyaerylainide gel electrophoresis (SDS-PAGE) was ran in tris-glycine SDS buffer. Differences among the isolates investigated were assessed on the base of the presence or absence of marked proteins bands. The molecular mass of the most significant bands was measured in kDa relatively to the low range SDS-PAGE standards of Bio-Rad.

Results and conclusions
M. fructigena, M. fructicola and M. laxa showed readly distinguishable since protein patterns gave marked and repeatable inter-specific differences but very little intra-specific variation. The banding patterns were exactly the same for each species or differed at most by one or two minor bands. Though differences were evident among M. fructigena isolates, it was possible to distinguish this species from both M. fructicola, and M. laxa. M. fructicola, and M. laxa showed more similar, with slight differences between the group of bands between 62 and 45 kDa.

Funding from the Commission of the EC Agriculture and Fisheries programme (FAIR, CT95-0725) is gratefully acknowledged.

References
1. Batra LR, 1991. Mycological Memoir no. 16. J. Cramer. Berlin, Germany.
2. Corazza L, et al., 1998. Abstract in ICPP98.