INVESTIGADORES
CIVELLO Pedro Marcos
artículos
Título:
An expansin gene expressed in ripening strawberry fruit.
Autor/es:
PEDRO MARCOS CIVELLO; POWELL A; SABEHAT A; BENNETT AB
Revista:
PLANT PHYSIOLOGY.
Editorial:
American Society of Plant Physiologists
Referencias:
Año: 1999 vol. 124 p. 1273 - 1279
ISSN:
0032-0889
Resumen:
Tissue softening accompanies the ripening of many fruit and initiates the
processes of irreversible deterioration. Expansins are plant cell wall proteins
proposed to disrupt hydrogen bonds within the cell wall polymer matrix. Expression
of specific expansin genes has been observed in tomato (Lycopersicon esculentum) meristems, expanding
tissues, and ripening fruit. It has been proposed that a tomato
ripening-regulated expansin might contribute to cell wall polymer disassembly
and fruit softening by increasing the accessibility of specific cell wall polymers to hydrolase action. To assess whether
ripening-regulated expansins are present in all ripening fruit, we examined
expansin gene expression in strawberry (Fragaria 3 ananassa Duch.). Strawberry differs significantly from tomato in that the
fruit is derived from receptacle rather than ovary tissue and strawberry is
non-limacteric. A full-length cDNA encoding a ripening-regulated expansin,
FaExp2, was isolated from strawberry fruit. The deduced amino acid sequence of
FaExp2 is most closely related to an expansin expressed in early tomato
development and to expansins expressed in apricot fruit rather than the previously
identified tomato ripening-regulated expansin, LeExp1. Nearly all previously identified ripening-regulated genes in strawberry are
negatively regulated by auxin. Surprisingly, FaExp2 expression was largely
unaffected by auxin. Overall, our results suggest that expansins are a common
component of ripening and that non-climacteric signals other than auxin may coordinate the onset of
ripening in strawberry.