ISSN:
1432-2048
Keywords:
Key words: Rachis elongation
;
Ethylene
;
Expansin
;
Marsilea
;
Regnellidium
;
Submergence
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract. To investigate the evolutionary history of expansins and their role in cell elongation in early land plants, we isolated two α-expansin genes, Mq-EXP1 and Rd-EXP1, respectively, from the semiaquatic ferns Marsilea quadrifolia L. and Regnellidium diphyllum Lindm. The deduced amino acid sequences of the fern expansins exhibit a high degree of identity to those of seed plants, showing that expansin genes were conserved during the evolution of vascular plants. Gel-blot analysis of M. quadrifolia and R. diphyllum genomic DNA indicated that, in both ferns, α-expansins are encoded by multigene families. Expression of α-expansin genes probed with Mq-EXP1 was confined to the elongating region of the Marsilea rachis. Cell-wall proteins of M.␣quadrifolia induced in-vitro extension of acidified cucumber cell walls. In R. diphyllum, expression of Rd-EXP1 increased when elongation of the rachis was enhanced by submergence or ethylene. These results indicate that α-expansins act as wall-loosening proteins in ferns, as has been proposed for angiosperms. In addition, Rd-EXP1 may play a role in mediating elongation of the rachis in submerged plants.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004250000367
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