Using mutants to probe the in vivo function of plastid envelope membrane metabolite transporters
During the last 15 years, much progress has been made in discovering genes encoding solute trans- porters of the inner plastid envelope membrane. For example, genes encoding transporters for phos- phorylated intermediates, dicarboxylates, adenine nucleotides, inorganic anions, and monosaccharides have been cloned. In many cases, the corresponding proteins have been expressed in recombinant host systems for further functional studies, thus allowing detailed in vitro characterization of transporter properties. Knowledge of the gene sequences encod- ing these transporters have allowed reverse-genetic approaches to study transporter function in vivo. Antisense repression and T-DNA insertion muta- genesis have provided a range of transgenic and mutant plants in which the activity of specific plastid envelope transporters are massively decreased or abolished. Plants with altered transporter activities represent excellent tools to probe the in vivo function of these transporters. Moreover, changing the perme- ability of the plastid envelope membrane permits the targeted manipulation of subcellular metabolite pools.
Published in 2010.