Molecular cloning and characterization of salt responsive genes in rice (Oryza sativa)

Differential screening was performed on a cDNA library made from RNAs isola ted from rice seedlings (variety TSA2), grown in water culture with 3 h osm otic shock (150mmol/L NaCl). Sixteen cDNA clones showing preferential hybri dization to RNA from salt shocked seedlings were isolated. Three clones enc oding salt responsive protein were selected by Northern hybridization study , One of the clones OSSRI represented a gene that is expressed at high leve ls during 24 In NaCl treatment. The DNA sequence analysis of OSSRI indicate d a similarity to the deduced amino acid sequence of inositol phosphate kin ase like protein of Arabidopsis thaliana. Another clone OSSRII showed Ident ity to the photosystem II reaction center W protein of Arabidopsis thaliana . The clone OSSRIII was highly similar to cysteine proteinase inhibitor whi ch is strongly associated with a chilling inducible and drought tolerant pr otein. Hybridization of the clone OSSRI to genomic DNA digested with EcoR1, EcoRV, HindIII, and Sal1 indicated that a single copy of the gene encoded the salt inducible transcript. RNA blot hybridization showed that mRNA of 1 .3, 1.0, 0.9kb for the clones OSSRI, OSSRII and OSSRIII, respectively, accu mulated over time up to 24 h.