Answer:
the genotype of the bacteria in this E.coli colony is arg^+leu^-met^+
Explanation:
The organism which, due to the lack of particular genes, can not synthesize a particular metabolite or nutrient by itself and needs the nutrient to the growing supplement is called auxotroph. The colony E.coli began to grow on a limited medium with arginine and leucine, and not with arginine and methionine in the above mentioned case. Leucine is therefore a vital metabolite required to grow bacteria and bacteria that do not contain the leu gene.
Therefore. the genotype of the bacteria in this E.coli colony is arg^+leu^-met^+
