JXB Advance Access originally published online on June 27, 2006
Journal of Experimental Botany 2006 57(10):2401-2411; doi:10.1093/jxb/erj213
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Published by Oxford University Press [2006] on behalf of the Society for Experimental Biology.
RESEARCH PAPER |
The strawberry gene FaGAST affects plant growth through inhibition of cell elongation

1Departamento de Biología Molecular y Bioquímica, Universidad de Málaga, 29071 Málaga, Spain
2Departamento de Biología Vegetal, Universidad de Málaga, 29071 Málaga, Spain
To whom correspondence should be addressed. E-mail: valpuesta{at}uma.es
The strawberry (Fragariaxananassa) FaGAST gene encodes a small protein with 12 cysteine residues conserved in the C-terminal region similar to a group of proteins identified in other species with diverse assigned functions such as cell division, elongation, or elongation arrest. This gene is expressed in the fruit receptacle, with two peaks during ripening at the white and the red-ripe stages, both coincident with an arrest in the growth pattern. Expression is also high in the roots but confined to the cells at the end of the elongation zone. Exogenous application of gibberellin increased the transcript level of the FaGAST gene in strawberry fruits. Ectopic expression of FaGAST in transgenic Fragaria vesca under the control of the CaMV-35S promoter caused both delayed growth of the plant and fruits with reduced size. The same growth defect was observed in Arabidopsis thaliana plants overexpressing FaGAST. In addition, the transgenic plants exhibited late flowering and low sensitivity to exogenous gibberellin. Taken together, the expression pattern, the regulation by gibberellin, and the transgenic phenotypes point to a role for FaGAST in arresting cell elongation during strawberry fruit ripening.
Key words: Cell elongation, cysteine-rich protein, Fragaria, gibberellin, fruit ripening, fruit size