Recombinant expression of Cry1Ac Bacillus thuringiensis protein in Yarrowia lipolytica and biological characterization against Lepidopteran pests

Improvement of the toxic properties of bioinsecticides based in Bacillus thuringiensis (Bt) is a current challenge inside of biological control. The genetic expression in eukaryotic systems is an industrial need of high interest.  Moreover, Bt is an important bacterium with high biotechnological interest. The Cry proteins have been expressed in various systems. We carry out the heterologous expression of cry1Ac gen from B. thuringiensis in the yeast Yarrowia lipolytica.  The purpose of this study was to clone the cry1Ac gene and evaluate the biological activity against insect pests. We cloned the cry1Ac gen in two vectors. The first is a replicative vector (pRRQ1) and the second is an integrative vector (pYLEX1). Two sequences were cloned in each vectors, the cry1Ac gen complete (ORF or protoxin) and the sequence related with  the toxic part. Four constructions were made and the sequence was confirmed by sequencing, while the expression by immunodetection. Preliminar toxic effect was observed against some lepidopterans as Spodoptera exigua and Spodoptera frugiperda. The complete toxicological characterization to determinate the LC₅₀ and LT₅₀ were further evaluated.