Genetic structure of a Mycosphaerella cryptica population

We studied the genetic structure of Mycosphaerella cryptica following natural infection of Eucalyptus globulus in a genetic trial. Results from this study indicated significant genetic variation within, and between, E. globulus families (three cloned and control-crossed F 2 and four open-pollinated...

Full description

Saved in:
Bibliographic Details
Published in:Australasian plant pathology 2005-01, Vol.34 (3), p.345-354
Main Authors: Milgate, Andrew W, Vaillancourt, Rene E, Mohammed, Caroline, Powell, Mike, Potts, Brad M
Format: Article
Language:English
Subjects:
Biotypes
Eucalyptus
Eucalyptus globulus
Genetic distance
Genetic diversity
Genetic structure
Genotypes
Hybrids
Infection
mating system
Mycosphaerella
Plantations
Polymerase chain reaction
population structure
Random amplified polymorphic DNA
recombination
resistance
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We studied the genetic structure of Mycosphaerella cryptica following natural infection of Eucalyptus globulus in a genetic trial. Results from this study indicated significant genetic variation within, and between, E. globulus families (three cloned and control-crossed F 2 and four open-pollinated families). Single-ascospore isolates were sampled from 72 E. globulus trees with contrasting levels of resistance within the trial, 21 E. nitens trees in an adjacent plantation, and five distant Eucalyptus plantation trees (two E. globulus 100–2400 km; two E. nitens 50–2200 km; one E. grandis × E. tereticornis hybrid 1500 km from the trial). Deoxyribonucleic acid from these isolates was scored for the presence/absence of 75 random amplified polymorphic DNA (RAPD) loci. Only 18 RAPD genotypes, which appeared to recombine rarely, were present among the 98 isolates, which indicates that M. cryptica is not strictly heterothallic. Cluster analysis using genetic distance revealed that M. cryptica genotypes from the field trial grouped into two clusters that matched differences in isolate culture morphology, indicating that the fungal population comprised two distinctive biotypes. The two biotypes differed markedly in their host interactions. Biotype 2 was found only on E. globulus , whereas biotype 1 infected both E. globulus and E. nitens eucalypt species. Within E. globulus , biotype 2 was almost exclusively collected on resistant trees whereas biotype 1 was found on both resistant and susceptible trees. The hypothesis that there could be specialisation of M. cryptica biotypes occurring at two levels, among host species and within host species, is discussed.
ISSN:0815-3191
1448-6032
DOI:10.1071/AP05044