Pathogens were isolated from heavily infected jackfruit of seven
different locations of Birbhum and Burdwan districts in the month
of February (Average day temperature, high 28 C, low 12 C, clear
sunny days). Based on light microscopic observations it was found
that the isolated pathogens from all of the localities showed more
or less similar morphology and were identified as Rhizopus sp.
(Fig. 2). When they were cultured on malt agar plates, white, cottony
mycelia were observed and on maturation blackish spores
were developed from those mycelia. Microscopic observation
reveals aseptate vegetative hyphae, bunch (2–5) of sporangiophores
from nodes, below which presence of rhizoids and stolons
connecting the nodes indicating the isolates as species of Rhizopus.
VBAM1, one of the representative strains isolated from a heavily
infected young fruit and which was surface sterilized before isolation
was selected arbitrarily for further studies. Based on the 28S
rDNA sequence homology and phylogenetic analysis (Fig. 3) the
isolated pathogen VBAM1 was identified as Rhizopus stolonifer.
Consensus sequence of 611 bp of D1/D2 region of 28S rDNA gene
was generated from forward and reverse sequence data using
aligner software. It has been reported by several workers that several
species of Rhizopus viz. R. artocarpi (Roy, 1983) R. oryzae, R.
stolonifer, etc. can cause the fruit rot of jackfruit in different parts
of the world (Nelson, 2005). Thus the present observation corroborates
with the earlier findings.
Degradation of pectic components