M. Laday et A. Szecsi, Distinct electrophoretic isozyme profiles of Fusarium graminearum and closely related species, SYST APPL M, 24(1), 2001, pp. 67-75
Cellulose-acetate electrophoresis (CAE) was used to investigate isozyme pol
ymorphisms among different isolates of Fusarium cerealis, F. culmorum, F. g
raminearum and F. pseudograminearum from around the world. After initial te
sting of 22 enzymes in three buffer systems for activity and resolution of
bands, 12 proved to be appropriate for analysis of the full sample set. Rem
arkably uniform isozyme patterns were obtained intraspecifically, irrespect
ive of the geographical origin of the isolates or the host/substratum from
which they were isolated. This result indicated that isolates within a give
n species are descendant from a same ancestral population. Comparing the di
fferent electrophoretic types (ETs), adenylate kinase (AI(), NADP dependent
glutamate dehydrogenase (NADP GDH), peptidase B (PEP B), peptidase D (PEP
D) and phosphoglucomutase (PGM) proved to be diagnostic for at least one sp
ecies examined. However, only PEP D was useful alone as a marker to disting
uish the four taxa studied providing a rapid and simple CAE based diagnosti
c protocol. Cluster analysis of band sharing coefficients grouped the isola
tes into four distinct groups corresponding to the 4 species studied. Isola
tes of F. cerealis were clustered between those of F. culmorum and F, grami
nearum corroborating their known close relationship to both species. For co
mmon ETs, the similarity values between F. cerealis and F. culmorum and bet
ween F. cerealis and F. graminearum were the same. Furthermore, the similar
ity values and the resulting phenogram indicated that F. graminearum is mor
e closely related to E: cerealis and F. culmorum than to F. pseudograminear
um, thus the morphological similarity of F. graminearum and F. pseudogramin
earum does not reflect their genetic relationship. This fact supports the s
pecies status of F. pseudograminearum.