Abstract
Acaryochloris spp. contains chlorophyll (Chl) d as a major Chl and also a small amount of Chl a, and can utilize infrared light for photosynthesis. Recently, the complete genome of the type strain, Acaryochloris marina MBIC 11017, was sequenced, however, lack of a genetic technique prevented us from studying A. marina intensively by a molecular genetic approach. In this study , we developed the technique for gene transfer into A. marina, and succeeded in producing a transformant expressing a foreign gene. First, we produced an expression vector from a broad-host range plasmid, and tried to introduce the vector into A. marina by conjugal gene transfer. Colonies obtained by antibiotic selection retained the vector. Then, we produced a transformant expressing chlorophyllide a oxygenase gene (CAO) that involved in Chl b biosynthesis. The pigment composition of the transformant was analyzed by HPLC, and the accumulation of a novel pigment was found. Based on the absorption spectrum, we estimated it to be a Chl derivative. The chemical structure, properties and proposed biosynthetic pathway of the novel Chl will be discussed.
