Journal of Environmental Biology

Effect of different environmental conditions on growth and

sporulation of some Trichoderma species

A. Zehra*, M. K. Dubey, M. Meena and R. S. Upadhyay

Laboratory of Mycopathology and Microbial Technology, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi-221 005, India

*Corresponding Author E-mail: zandleeb143@gmail.com

Key words

Alternaria alternata,

Antagonism,

Extracellular enzymes,

Fusarium oxysporum,

Radial growth,

Trichoderma spp.

Publication Data

Paper received : 22.04.2016

Revised received : 14.06.2016

Re-revised received : 05.08.2016

Accepted : 12.09.2016

Abstract

Aim: To evaluate the effect of the different environmental conditions (temperature, pH and salt) on growth and sporulation of some Trichoderma species.

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Methodology: In the present study, Trichoderma spp. were isolated from rhizospheric soil of various cultivated plants and identified as Trichoderma harzianum, T. viride, T. hamatum and T. asperellum on the basis of morphological and conidial characteristics. These identified Trichoderma spp. were tested in vitro for their antagonistic activity against Fusarium oxysporum and Alternaria alternata, enzyme production and tolerance to different environmental conditions such as salt, temperature and pH.

Results: The results obtained revealed that out of the four tested Trichoderma species, maximum inhibition of the growth and spore production of both the pathogens were found by T. harzianum, with the greatest percent inhibition was observed for F. oxysporum (68.5%) and A. alternata (52.93%) in dual cultures. The inhibition rate was also significantly correlated with the culture filtrate of all the isolates. Significant chitinase and cellulase acttivities of all Trichoderma isolates have been recorded during plate assay. T. harzianum exhibited a higher diameter of clear zone than the other Trichoderma spp. on media containing chitin and cellulose. Thus, they showed a better cellulolytic and chitinolytic actitivties as compared to other isolates.? However, all these isolates responded distinctly to different environmental parameters. The most favourable temperature for growth and sporulation of T. harzianum and T. viride was found in between 25-40?C, where as for T. asperellum and T. hamatum, it was 25-35?C. Similarly, the most favourable range of pH was in between 4.6-7.6 for all the four spp. of Trichoderma. None of the applied NaCl concentrations except 1000 ?M significantly inhibited mycelial growth of all tested Trichoderma species.

Interpretation: On the basis of this study, it can be concluded that T. harzianum is a potential candidate as a biocontrol agent against various fungal pathogens in agriculture system under different environmental stresses. 

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