Barkan Lab

Photosynthetic Mutant Library

Mutant Corn LineupThe Photosynthetic Mutant Library (PML) is a large collection of Mu transposon-induced non-photosynthetic maize mutants. The collection consists of ~2100 independently-arising mutants, each with an accompanying pedigree, and many with chloroplast protein and RNA “snapshots” that elucidate gene function. PML is used to recover insertions in genes of known sequence (reverse-genetics), and for phenotype-driven forward-genetic discovery. Based on the distribution of alleles recovered to date, the collection is near saturation for genes whose disruption results in a decrease in seedling leaf chlorophyll, the easily scored read-out of disrupted chloroplast biogenesis we used to assemble the collection (see Figure). Most PML mutants are seedling lethal due to their photosynthetic defects. We estimate that the collection represents ~600 genes, each with 3-4 mutant alleles. We believe that the collection includes mutant alleles of most genes in maize that are necessary for the biogenesis of a photosynthetically-competent chloroplast. Mutant alleles analyzed in detail thus far disrupt various aspects of chloroplast gene expression (e.g. RNA splicing, RNA stabilization, translational activation) and thylakoid protein targeting (the cpSec, tat, and cpSRP pathways).

Table listing mutants recovered from the PML collection whose underlying Mu insertion has been identified.