Abstract:Osmotic stress caused by dehydration or high-salt conditions poses a major environmental challenge for plant growth and development. Many studies have shown that protein kinases are important regulators during osmotic stress in plants. In the present study, we describe GmAAPK, a soybean (Glycine max (L.) Merr.) gene coding for a putative serine/threonine protein kinase (abscisic acid (ABA)-activated protein kinase (AAPK)). The cDNA for GmAAPK is 1 409 bp long and contains a single long open reading frame representing a complete coding region of 359 amino acids. GmAAPK was mapped onto the D1a+Q linkage group. Its transcripts are expressed in all tissues, but at high levels in the cotyledon. GmAAPK mRNA was induced by polyethylene glycol, ABA, Ca2+, and Na+, but not cold (4 °C) treatments in soybean leaves. The results suggest that GmAAPK may participate in the regulatory process during osmotic stresses in soybean.(Author for correspondence.Tel: 010 6488 6859; Fax: 010 6487 3428; E-mails:jszhang@genetics.ac.cn and sychen@genetics.ac.cn)