Using specialized transduction for allelic exchange, null kasB mutants, but not kasAmutants, could be generated in Mycobacterium smegmatis, suggesting that unlike kasB, kasA is Toconfirm the essentiality of kasA, and to detail the molecular events that occur following depletion of KasA, wedeveloped CESTET (conditional expression specialized transduction essentiality test), a genetic tool thatcombines conditional gene expression and specialized