Abstract
The phytohormone abscisic acid (ABA) has been proposed as a common mediator controlling adaptive plant responses to a variety of environmental stresses, including water deficit, salinity, wounding, and low temperature. We have recently isolated three cDNAs, pUM90-1, pUM90-2, and pUM91-4, from a cDNA library of ABA-induced mRNAs of alfalfa. These cDNA clones exhibit a very high degree of sequence homology with one another and sequence similarities with certain regions of several stress- and ABA-inducible genes. The polypeptides encoded by these cDNAs are very rich in glycine (35-40%), histidine (7-15%), asparagine (8-14%), and tyrosine (5-10%) and have no tryptophan and proline. All of the encoded polypeptides contain characteristic tandem repeats comprising glycine residues intercepted with histidine and/or tyrosine. The RNAs corresponding to a representative cDNA, pUM90-1, were induced after treatment of seedlings with low temperature, drought, salt, and wounding stress, but not by heat; the induction was maximal under low temperature treatment. ABA and ABA analog rapidly induced the expression of these genes, whereas gibberellic acid treatment exhibited no induction whatsoever. These genes appear to be specifically induced in the shoot tissues. Analysis of ABA induction of genes corresponding to pUM90-1 in alfalfa seedlings of different age groups demonstrated that these genes were inducible in seedlings/plants of all age groups examined. Taken together these results suggest that these cDNA clones encode a group of proteins that are inducible by ABA and multiple environmental stresses and correspond to a new family of genes of plants, designated as ABA- and environmental stress-inducible genes.
Highlights
From the $Department of Plant Science and the $Department of Immunology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
The RNAs corresponding to a representative to both stress and abscisic acid (ABA); (ii) a set of mRNAs/proteins that cDNA,pUM90-1, were induced after treatment of seedlings with low temperature, drought, salt,and wounding stress, but not by heat; the induction was maximal under low temperature treatment
The 3' end untranslatedregions of the four cDNAs differ inlength,aconsensus sequence of"AATAAA" for polyadenylation is found in pUM91-4, and a consensus sequence of "TATAAA is found in pUM9O-1 and pUM90-2
Summary
From the $Department of Plant Science and the $Department of Immunology, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada. Several investigators have reported the accumulation of specific gene products during low temperature acclimation (Meza-Basso et al, 1986;Guy and Haskell, 1987; Robertson et al, 1987; Mohapatra et al, 1987,1989; Dhindsa and Mohapatra, 1990), water deficit (Mundy and Chua, 1988; Skriver and Mundy, 1990),dehydration (Robertson et al, 1989;Close et al, 1989), salt stress (Ramagopal, 1987; Singh et al, 1987a, 1987b),or in response all age groups examined Taken together these results to wounding of plant tissues (Bradshaw et al, 1989; Palm et suggest that these cDNA clones encode a group of pro- al., 1990). The abbreviations used are: ABA, abscisic acid; A/ES, ABA- and environmental stress-inducible; SDS, sodium dodecyl sulfate; ELISA, enzyme-linked immunosorbent assay; GA,, gibberellic acid
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
