Chitinase from <i>Pseudomonas fluorescens</i> and its insecticidal activity against <i>Helopeltis theivora</i>

The tea mosquito bug (TMB), Helopeltis spp.
(Hemiptera: Miridae) is an insidious pest that poses
a significant economical threat to tea plantations.
Pseudomonas cultures are being used extensively
for pest management which, however, resulting in
a low mortality rate of insects and which has
prompted us to search for a new microbial
metabolite for TMB control. A chitinase purified
from P. fluorescens and partially characterized by
our group showed insecticidal activity against
TMB. The mode of action behind chitinase toxicity
is the enzymatic hydrolysis of chitin, which is a
common constituent of the insect exoskeleton and
gut lining of the peritrophic membrane. A chitinasesecreting strain MP-13 was characterized based on
16S rRNA sequencing and validated as Pseudomonas fluorescens. In the present study, purified
chitinase (0.048 units/ml) enzyme from P.
fluorescens MP-13 revealed 100% TMB mortality
under in-vitro conditions. The results of this study
can be utilized for future crop improvement programs and integrated pest management strategies.