Chloroplast protein import in Passiflora edulis involves well conserved TOC but is undergoing drastic changes in composition of TIC

Chloroplast protein import across the outer and inner envelope membranes is mediated successively by two protein translocons termed TOC and TIC, respectively. While compositions of these megacomplexes are broadly conserved in plants, there are interesting exceptions. One such is the case of Passiflora edulis, whose previous transcriptomic studies anticipated rapid evolutionary changes in components being involved in chloroplast protein import. However, their biochemical characterizations are completely lacking. Here, we show that Passiflora edulis chloroplasts possess 800-1000 kDa large TOC containing well-conserved Toc159, Toc75, and Toc34. Interestingly, non-photosynthetic type Tic20 was identified in the envelope membranes of leaf chloroplasts, despite the absence of typical photosynthetic type TIC constituents. Hence, in Passiflora edulis, non-photosynthetic type TIC may function also in photosynthetic tissues and collaborate with the well-conserved TOC.