Shree Kumar Apte
Bhabha Atomic Research Centre, India
Title: Engineering cyanobacterial nitrogen bio-fertilizer for rice cultivation in stressful environment
Biography
Biography: Shree Kumar Apte
Abstract
As a naturally abundant, photosynthetic, nitrogen-fi xing microbe, the cyanobacterium Anabaena contributes signifi cantly to
the nitrogen and carbon economy of tropical soils, especially in cultivation of rice paddy. However, its nitrogen bio-fertilizer
potential is adversely aff ected by common abiotic stresses. Engineering enhanced nitrogen fi xation and stress tolerance capabilities
in this microbe through genetic manipulation is seriously limited due to the unavailability of appropriate tools and techniques
and knowledge of suitable candidate genes. In recent years, our laboratory has devised an electroporation protocol for genetic
transformation that achieves high frequency gene transfer and overcomes problems associated with the current practice of triparental
conjugation between E. coli strains and Anabaena. We have also constructed (a) a suitable vector for new gene discoveries,
and (b) a novel integrative expression vector pFPN, placing desired genes at a defi ned locus in Anabaena genome and facilitates their
high level expression from an eco-friendly light-inducible promoter. Using these tools we have identifi ed several genes responsible
for enhanced heterocyst formation and nitrogen fi xaton (hetR), chaperones (groESL, cpn60) for protein folding and homeostasis, and
several oxidative stress tolerance genes (superoxide dismutases, catalases and peroxiredoxins) which confer superior stress tolerance
to Anabaena. Th e approach has proved very useful for constructing recombinant Anabaena strains capable of nitrogen fi xation in
stressful environments.