Constitutive over-expression of AtGSK1 induces NaCl stress responses in the absence of NaCl stress and results in enhanced NaCl tolerance in Arabidopsis

Piao, HL Lim, JH Kim, SJ Cheong, GW Hwang, I

Hl. Piao et al., Constitutive over-expression of AtGSK1 induces NaCl stress responses in the absence of NaCl stress and results in enhanced NaCl tolerance in Arabidopsis, PLANT J, 27(4), 2001, pp. 305-314

36

INGLESE

Article

Plant Sciences","Animal & Plant Sciences

PLANT JOURNAL

0960-7412 → ACNP

27

4

2001

305 - 314

ISI

0960-7412(200108)27:4<305:COOAIN>2.0.ZU;2-J

GSK3/shaggy-like protein kinases have been shown to play diverse roles in d evelopment and signal transduction pathways in various organisms. An Arabid opsis homologue of GSK3/shaggy-like kinase, AtGSK1, has been shown to be in volved in NaCl stress responses. In order to further clarify the role of At GSK1 in NaCl stress responses in plants, we generated transgenic Arabidopsi s plants that overexpressed AtGSK1 mRNA. These plants showed enhanced resis tance to NaCl stress when assayed either as whole plants or by measurement of root growth on NaCl plates. In addition, AtGSK1 transgenic plants in the absence of NaCl stress showed phenotypic changes, such as accumulation of anthocyanin, that were similar to those observed in wild-type plants under NaCl stress. Transgenic plants accumulated 30-50% more Na+ than did wild-ty pe plants when subjected to NaCl stress, and Ca2+ content was increased by 15-30% in the transgenic plants regardless of the NaCl stress level. Northe rn blotting revealed that AtGSK1 over-expression induced expression of the NaCl stress-responsive genes AtCP1, RD29A and CHS1 in the absence of NaCl s tress. In addition, AtCBL1 and AtCP1 were superinduced in the NaCl-stressed transgenic plants. Taken together, these results suggest that AtGSK1 is in volved in the signal transduction pathway(s) of NaCl stress responses in Ar abidopsis.