Our work focusses on the assessment and elucidation of the cost-benefit interactions
of a special group of microorganisms known as endophytes which inhabit the internal
tissues of the host plants without causing any immediate negative effect, and remain
in a mutualistic association for at least a part of their life cycle. Plants are known
to produce various bioactive secondary metabolites as defensive compounds. Cannabinoids
are the most extensively studied secondary metabolites of Cannabis sativa L. plants. Recent work on liverworts like Radula marginata led to the identification of new cannabinoids with structural similarity to tetrahydrocannabinol,
the major psychoactive compound of Cannabis plants. We have isolated a plethora of endophytes, both fungi and bacteria, from
R. marginata. Since both Radula and Cannabis contain similar biosynthetic principles, we are evaluating the biocontrol potential
of the endophytes against the host specific phytopathogens of C. sativa L. plants namely, Botrytis cinerea (causing gray mold disease) and Trichothecium roseum (causing pink rot disease), respectively.
We are investigating the various attack-defense-counterdefense responses of the isolated
endophytes when challenged by the phytopathogens. These responses trigger the production
of secondary metabolites or intermediates which are otherwise 'cryptic'. We are not
only analyzing the various cost-benefit tradeoffs between the endophytes and host
plants but also evaluating the bioactive target and/or non-target metabolite production
correlating to the endophyte-pathogen interactions. This will enable us in understanding
the biochemical fingerprint of the endophytes which aid in thwarting the phytopathogens
and reducing the loss of such therapeutically beneficial plants.
References:
[1] Kusari et al. (2012) Fungal Divers In Press (doi. 10.1007/s13225 – 012 – 0216
– 3)
[2] Kusari et al. (2013) In: Kharwar R.N. (ed.) Endophytes, (ICPMB 2012), Springer-Verlag,
Heidelberg. In Press
