ISSN:
1573-4927
Keywords:
Oryza sativa
;
O. glaberrima
;
Wx protein
;
starch synthase
;
immunological assay
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Normal (nonglutinous) rice plants (Oryza sativa andO. glaberrima) contain more than 18% amylose in endosperm starch, whilewaxy (glutinous) plants lack it in this starch. In contrast, leaf starch contained more than 3.6% amylose even inwaxy plants. SDS-PAGE analysis of proteins bound to endosperm starch granules in the normal plants revealed a single band with aMr of 60 kd, whereaswaxy plants did not exhibit a similar band. The activity of starch synthase (NDP-glucose-starch glucosyltransferase) was completely inhibited by antibody against the 60-kd protein. Thus, we conclude that the 60-kd protein is thewaxy protein encoded by theWx allele, which also plays a role in the synthesis of nonglutinous starch in endosperm tissue. In leaf blades, the proteins bound to starch granules separated into five bands withMr's of 53.6 to 64.9 kd on SDS-PAGE. Analysis of these proteins by immunoblotting using antiserum againstWx protein and inhibition of starch synthase activity by the synthase antibody revealed that none of these proteins was homologous toWx protein. We suggest that the synthesis of amylose in leaf blades is brought about by a protein encoded by a gene(s) different from theWx gene expressed in the endosperm.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00554138
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