Targeted Isolation and Characterization of T-DNA Mutants Defective in Photorespiration

Transfer DNA (T-DNA) insertional lines have facilitated reverse genetic approaches in plant science and considerably accelerated the functional characterization of genes. Typically, online databases of mutant collections are searched for suitable mutant alleles of the gene of interest (GOI). Before such lines can be characterized physiologically, the genotype of the respective mutant has to be verified followed by the quantitative examination of downstream effects on the levels of the respective mRNA and the encoded protein. Here, we describe a typical workflow for the identification of photorespiratory mutants followed by phenotypic characterization according to growth under different conditions, photosynthesis on the levels of chlorophyll a fluorescence and gas exchange, and metabolite analysis.