Heat Shock Proteins in Cassia Species

Abstract

Aim: Abiotic stresses, such as drought, salinity, extreme temperatures, chemical toxicity and oxidative stress, are serious threats to plants. Heat shock proteins can assist in protein refolding under stress conditions at molecular levels. The proposed study was aimed to analyze and characterize the heat shock proteins at the molecular level in the Cassia species. Study Design: The experiments designed were intended to study and characterize the heat shock proteins in the Cassia species using molecular approach. Methodology: The samples were subjected to the varying heat treatments (30⁰C, 37⁰C and 42⁰C), and the proteins obtained were further sequenced for similarity search. The peptide sequence was synthesized chemically and conjugated with Keyhole limpet hemocyanin (KLH) for the production of antibodies. Western blot was carried out with the polyclonal antibodies to confirm the results. Results: The gel analysis revealed a clearly visible over-expressed band at the highest induced temperature (42ºC) depicting the presence of a heat shock response in Cassia. BLASTp search of the peptide sequences obtained from trypsin digestion followed by LC-MS resulted in 14 hits, out of which one of the peptide was similar to a known HSP, thioredoxin peroxidase from Nicotiana tabacum. Rabbit polyclonal antibodies were synthesized against the KLH-tagged peptide. The Western blot confirmed binding of probes to the heat shock band observed for the temperature treatment at 42ºC. Conclusions: The obtained stress proteins can be used as molecular biomarkers for identifying the structural adaptive changes in plants based on their ecological habitats. The study can also help us in synthesizing the HSPs which could aid in protecting the plants against heat stress and maintain the homeostasis.