Expression, Purification and Bioassay of Cry55Aa protein against tomato root knot Nematode, Meloidogyne incognita

A nematicidal Cry55Aa protein was expressed and purified from E. coli cells. Higher level of expression was observed in culture induced with 0.1mM of IPTG after four hours of induction. The Cry55Aa protein was purified by resuspending the crude protein in solubilizing buffer at pH 12 for 120 min. When Meloidogyne incognita was tested against different concentration of purified protein, a clear dose response lethality was observed with an LC₅₀ value of 31.4μg/ml.