The complete chloroplast genome of parasitic flowering plant Monotropa hypopitys: extensive gene losses and size reduction

摘要

Plastid genomes of parasitic plants represent apt systems, in which the effects of relaxed selective pressure on photosynthetic function are studied. The complete chloroplast genome sequence of nonphotosynthetic mycoheterotrophic plant Monotropa hypopitys was determined. With only 19 protein-coding, four rRNA and 17 tRNA genes in 34 800 bp long genome, it is one of the most reduced plastid genomes characterized until now. Monotropa chloroplast genome lacks all genes encoding photosynthetic functions and RNA polymerase subunits but retains most of the ribosomal protein genes and housekeeping genes infA and matK. Monotropa represents the late stages of chloroplast genome decay following the transition to heterotrophy.