Photosynthetic genes are differentially transcribed during the dehydration-rehydration cycle in the resurrection plant, Xerophyta humilis.

One of the desiccation-tolerant mechanisms of the resurrection plant, Xerophyta humilis, is the ability to shut down photosynthesis reversibly. The X. humilis psbR and ChlP genes, encoding the 10 kDa polypeptide of photosystem II (PSII) and a geranylgeranyl reductase, respectively, were isolated in a differential display screen as dehydration-down-regulated and rehydration-up-regulated transcripts. Two other PSII genes, psbA (chloroplast-encoded) and psbP (nuclear-encoded), isolated by degenerate primer PCR, display a similar trend in expression.