DIVERSITY, ANTIMICROBIAL ACTIVITIES AND ASSOCIATED MICROBIOTAOF SOIL PENICILLIA FROM VIRGIN FOREST FLOOR

Abstract

The diversity of Penicillium spp. and associate mycobiota from different virgin forest
floor in the Brahmaputra Valley, Assam, India was analyzed. Soil samples were collected
from six different undisturbed forest floors together with seasonally flooded forest and also
from agricultural fields. Samples were taken from the litter and from three soil core i.e. 0-5,
10-15 and 30-35 cm in depth. The isolated fungal species were identified based on
morphological and reproductive characteristics. About 18 common fungal species from
different soil samples were isolated dominated by Penicillium sp. and Aspergillus sp. The
total fungal population found in the studied sites was 98.87 (±10.7) x103 CFU/g dry soils in
all the seasons in top soils. The total CFUs of Penicillium were also highest among the species
in all the sites (mean 18.73 ±1.1 x103 CFU/g; n=7) where 27.2 x103 CFU/g in summer and
11.6 x103 CFU/g dry soil in winter. Relative density of Penicillium sp. was also higher among
the associated fungi although relative density of Aspergillus (23.83) was higher than
Penicillium (19.39). Among the 30 isolates of Penicillium, few species have shown
antimicrobial activity against the tested bacterial pathogens. The cultural filtrate of four
different isolates showed antimicrobial activity against Streptococcus bombycis, Aeromonas
salmonicida, Staphylococcus aureus and E. coli having inhibition zone of about ≥10mm. All
the tested bacterial species were sensitive to six different Penicillium spp.