Nucleotide sequence of a cDNA clone encoding a dehydrin-like protein from Stellaria longipes.

The expression of many different genes is regulated by ABA and osmotic stress (Skriver and Mundy, 1990). These genes and their products have been characterized in severa1 plants, and they include dehydrins in barley, corn (Close et al., 1989), and Arabidopsis thaliana (Rouse et al., 1992); proteins responsive to ABA (RAB) in rice (Mundy and Chua, 1988; Yamaguchi-Shinozaki et al., 1989); TAS and le proteins in tomato (Godoy et al., 1990; Plant et al., 1991); late embryogenesis-abundant proteins in cotton (Baker et al., 1988); and osmotin in tobacco (Singh et al., 1987). Many of these proteins share a certain degree of structural similarity. Stellaria longipes Goldie (Caryophyllaceae) is a dicotyledonous herbaceous perennial (Chinnappa and Morton, 1984). As part of a project on evolutionary studies of the S. longipes complex, a leaf cDNA library was constructed from a natural population in the Kananaskis Valley, Alberta, Canada. A random cDNA clone (H26) was isolated (Table I), which, on sequencing, resembled previously reported dehydrins from barley and A. thaliana (Close et al., 1989; Rouse et al., 1992) and RAB from rice (Mundy and Chua, 1988; YamaguchiShinozaki et al., 1989). It was used to probe northern blots of total leaf RNAs from plants receiving different treatments. The hybridization showed that the H26 mRNA levels in leaves were inducible by treatments of ABA, PEG, or drought, whereas stems seemed nonresponsive. Although the overall structure is very similar to many other dehydrins, the S. longipes dehydrin exhibits certain different structural features (Table I). To our knowledge, this is the first DNA sequence ever reported from the genus Stellaria.