Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/1996
Publication Date: N/A
Interpretive Summary: How do plants perceive and respond to extrnal signals such as light, cold and moisture availability? A link between changes in the environment and plant responses may be protein kinases. These enzymes can activate other enzymes and regulate gene expression by phosphorylation. Protein kinases are major components of response pathways in animals, microorganisms and plants. Here we report the identification and DNA sequence of a wheat protein kinase gene that is induced in greening seedling tissue. The gene is not expressed in seeds, but is up-regulated when germinating seedlings are exposed to light. This is the first report of a protein kinase that is up-regulated in greening seedlings. This protein kinase gene has DNA sequence homology to a previously identified wheat protein kinase that is drought-stress responsive, suggesting that there is a sub-family of similar protein kinases in plants. The identification of this new plant protein kinase, including the sequence of the gene's regulatory region, provides plant scientists with a new tool for identifying the critical regulatory steps that control seedling emergence and crop stand establishment.
Technical Abstract: We have identified a new wheat PKABA1-like protein kinase gene, TaPK3, that is expressed in greening wheat seedlings. TaPK3 has high sequence homology (97% similarity with some sequence diversity at the 3'-end) to the wheat PKABA1 protein kinase mRNA, which is upregulated by cold temperature treatment, dehydration and abscisic acid (ABA). Use of a TaPK3 gene-specific probe has revealed the TaPK3 is differentially expressed with respect to PKABA1. TaPK3 mRNA accumulates in greening shoot tissue of wheat, but is not affected by dehydration, cold temperature treatment or ABA. Based on sequence and expression differences, we conclude that expression of the PKABA1-like protein kinases is not limited to stress responses.