Abstract:
Speci e s of Mycosphaerellaceae and
Teratosphaeriaceae (Ascomycetes) cause important leaf, shoot
and canker diseases globally on a broad range of hosts, including
Eucalyptus and other Myrtaceae. Recently, species of
the Mycosphaerellaceae and Teratosphaeriaceae have been
isolated as asymptomatic endophytes. In this study, endophytic
species of Mycosphaerellaceae and Teratosphaeriaceae
were isolated from samples taken from healthy native
Syzygium cordatum (Myrtaceae) and related non-native Eucalyptus
grandis x E. camaldulensis (hybrid clone) growing in
Mtubatuba, KwaZulu Natal, South Africa. Multi-locus sequence
analysis (MLSA) using the Internal Transcribed Spacer
(ITS) region, the partial Large Subunit (LSU; 28S nrDNA)
of the nuclear ribosomal DNA operon and Translation Elongation
Factor-1α (TEF-1α) genes were used to correctly
identify the 22 resulting isolates. The isolates grouped in five
clades representing Readeriella considenianae that was isolated
only from the Eucalyptus hybrid clone, Mycosphaerella
marksii and M. vietnamensis from S. cordatum and
Pseudocercospora crystallina from both S. cordatum and the
Eucalyptus hybrid clone. Interestingly, the serious canker
pathogen T. zuluensis was isolated from Eucalyptus leaves,
although it is known only from stem and branch cankers. Of
the species found, R. considenianae and M. vietnamensis were
found in South Africa for the first time, while M. marksii,
M. vietnamensis and P. crystallina were shown to naturally
infect native S. cordatum for the first time. Despite the limited number of trees sampled, the new host and distribution reports
show that more intensive sampling, especially following an
endophyte approach, will reveal more complete patterns of
host preference and geographical distribution for these fungi.
