クレプトプラスティ

有孔虫属のBulimina、Elphidium、Haynesina、Nonion、Nonionella、Nonionellina、Reophax、およびStainforthiaの一部の種は珪藻の葉緑体を隔離する。^{[ 4 ]}

The stability of transient plastids varies considerably across plastid-retaining species. In the dinoflagellatesGymnodinium spp. and Pfiesteria piscicida, kleptoplastids are photosynthetically active for only a few days, while kleptoplastids in Dinophysis spp., taken from cryptophytes,^[5] can be stable for 2 months.^[1] In other dinoflagellates, kleptoplasty has been hypothesized to represent either a mechanism permitting functional flexibility, or perhaps an early evolutionary stage in the permanent acquisition of chloroplasts.^[6]

Mesodinium rubrum is a ciliate that steals chloroplasts from the cryptomonadGeminigera cryophila.^[7]M. rubrum participates in additional endosymbiosis by transferring its plastids to its predators, the dinoflagellate planktons belonging to the genus Dinophysis.^[8]

Karyoklepty is a related process in which the nucleus of the prey cell is kept by the host as well. This was first described in 2007 in M. rubrum.^[9]

The first and only case of kleptoplasty within Euglenozoa belongs to the species Rapaza viridis, the earliest diverging lineage of Euglenophyceae. This microorganism requires a constant supply of a strain of Tetraselmis microalgae, which it ingests to extract chloroplasts. The kleptoplasts are then progressively transformed into ones that resemble the permanent chloroplasts of the remaining Euglenophyceae. Cells of Rapaza viridis can survive for up to 35 days with these kleptoplasts.^[10]

Kleptoplasty is considered the mode of nutrition of the euglenophycean common ancestor. It is hypothesized that kleptoplasty allowed for various events of horizontal gene transfer that eventually allowed the establishment of permanent chloroplasts in the remaining Euglenophyceae.^[10]

Two species of rhabdocoel marine flatworms, Baicalellia solaris and Pogaina paranygulgus, make use of kleptoplasty. The group was previously classified as having algal endosymbionts, though it was already discovered that the endosymbionts did not contain nuclei.^[11]

珪藻を摂取する際、B. solarisとP. paranygulus は、まだ解明されていないプロセスで、餌からプラスチドを抽出し、表皮下に組み込み、珪藻の殻と残りの部分を分離して消化します。B . solarisでは、抽出されたプラスチド、すなわち盗葉緑体は、約 7 日間という短い期間、機能的な光合成を続けます。この 2 つのグループは姉妹分類群ではなく、この形質はより近縁なグループ間で共有されていないため、盗葉緑体は 2 つの分類群内で独立して進化したという証拠があります。^{[ 12 ]}