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Abstract
Aim:
The present study was undertaken to study the morphological and molecular
diversity of Ganoderma spp. causing foot rot of arecanut in dry tracts of
Southern Karnataka.
Methodology: A total of 20 samples isolated from diseased areca
palms in three districts of Karnataka were identified based on morphological
and molecular characteristics. Qualitative data of cultural characteristics
were transformed into code and a binary matrix was generated. Total genomic
DNA was isolated and ITS region was amplified using universal primers ITS1
and ITS4. PCR amplicon was directly sequenced and phylogenetic analysis was
carried out.
Results:
The dendrogram generated from the cultural morphological characteristics
showed clear variations among Ganoderma isolates causing foot rot. DNA
amplification of Ganoderma isolates with fungal universal primers (ITS1 and
ITS4) was observed at 650 bp in all isolates tested. Taxonomic correlation of
isolates upon NCBI web proved that the isolates were genetically related to
Ganoderma spp. with 89-99.49 per cent identity and confirmed the taxonomic
identity of isolates used in this study.
Interpretation: Phylogenetic analysis of arecanut
isolates of southern Karnataka are distinct as evidenced by forming separate
cluster. Based on gene homology, G. ryvardenni and G. casuarinicola
are new species reported as causal agent of foot rot in arecanut from
Karnataka. The ITS gene sequences of four isolates viz., AG3
(MN 784436), AG4 (MN 784437), AG11 (MN 784438), and AG20
(MN 78449) were deposited in NCBI gene bank.
Key
words:
Arecanut, Foot rot, Ganoderma, Phylogeny, Species diversity
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