Two early light-inducible protein (ELIP) cDNAs from the resurrection plant Tortula ruralis are differentially expressed in response to desiccation, rehydration, salinity, and high light.

Tortula ruralis (Syntrichia ruralis) is a useful model system for the study of gene control in response to severe water deficit-stress. EST gene discovery efforts utilizing desiccated gametophytes have identified two cDNAs designated Elipa and Elipb with significant similarity to early light-inducible proteins (ELIPs). Elipa is 1006 bp in length, encoding a 212 amino acid deduced polypeptide (ELIPa) with a predicted molecular mass of 23.3 kDa and pI of 5.57. Elipb is 997 bp in length, encoding a 224 amino acid deduced polypeptide (ELIPb) with a predicted molecular mass of 24.4 kDa and pI of 9.27. Phylogenetic analysis demonstrated that ELIPa and ELIPb are reproducibly grouped with ELIP sequences derived from desiccation-tolerance tissues. RNA blot hybridization was used to analyse Elipa and Elipb mRNA abundance in response to a variety of stresses. Elipa steady-state transcript levels increased in response to slow desiccation, rapid desiccation/rehydration, salinity, ABA, and rehydration in high light. The Elipb transcript was only detectable in response to ABA or rehydration in high light. It is postulated that ELIPa and ELIPb are an adaptive response to stress-induced photodamage within the moss chloroplast, and play a key role in the protection and/or repair of the photosynthetic apparatus.