PLANT SCIENCES

Even Parasitic Plants Need Plastids

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Science  11 Mar 2011:
Vol. 331, Issue 6022, pp. 1243
DOI: 10.1126/science.331.6022.1243-a
CREDIT: DELANNOY ET AL., MOL. BIOL. EVOL. 28, 10.1093/MOLBEV/MSR028 (2011).

Plastids, such as the chloroplasts of plants, use photosynthesis as an essential energy source for plant cell function. Plastids probably arose from bacterial endosymbionts, and over time, most flowering plants, even those that no longer photosynthesize, have discarded many genes within their plastids. Delannoy et al. sequenced the plastid genome of the orchid, Rhizanthella gardneri. R. gardneri lives underground and is parasitic, meaning that it obtains its energy and nutrients indirectly by exploiting other plants. Its plastid, the smallest identified land-plant plastid to date, retained genes that are also found in other nonphotosynthetic parasitic plants that are not closely related. The genes appear to be transcribed and translated properly. These results suggest that all plant plastids contain key genes and transfer RNAs that function outside of photosynthesis, which explains their convergent retention among distant lineages of parasitic plants and may have implications beyond the plant kingdom.

Mol. Biol. Evol. 28, 10.1093/molbev/msr028 (2011).

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