2.2. Molecular characterization of the endophytes and Fusarium
isolates
2.2.1. DNA amplification and sequencing
The identification of endophytic and pathogenic fungi was performed
by means of nucleotide sequence of the ITS1-5.8S rRNAITS2
region that varies depending on fungal species. DNA was
extracted from small mycelial fragments scraped from the surface
of culture plates using a commercial kit (RedExtract-N-Amp Plant
PCR, Sigma Aldrich) as recommended by the manufacturer. The
ITS1-5.8S rRNA-ITS2 region was amplified using PCR in a system
including 2 ll of DNA extract and primers ITS4 and ITS5. Amplifi-
cation conditions were: 95 C for 2 min, followed by 35 cycles of
94 C for 1 min, 54 C for 1 min, and 72 C for 1 min after which
the reaction was kept at 72 C for 10 min. PCR amplicons were
purified by filtration (Montage PCR, Millipore), and sequenced in
a 3100 Genetic Analyzer (Applied Biosciences). Only one strand
of the PCR amplicon was sequenced. The sequencing reaction
was started at the 50
end of the ITS1-5.8S rRNA-ITS2 region, using
primer ITS4. The quality of the sequences obtained was analyzed
by means of sequencing reaction chromatograms, visualized with
Chromas 1.45 software (Technelysium, Australia) (Sánch