Characterization of Waxy microsatellite classes that are closely linked to the rice Waxy gene and amylose content in Thai rice germplasm

Abstract

Sixty-eight strains belonging to two species of Oryza were characterized by using Wx microsatellite, (CT)n repeats that are closely linked to the rice Waxy gene. These strains included high-, intermediate- and low-amylose strains as well as glutinous rice. The polymerase chain reaction (PCR) was used to amplify a DNA fragment including the beginning of exon 1 and the beginning of the intron 1 of the Waxy gene. The amplified DNAs were sequenced an ABI Model 377 automatic sequencer.Ten Wx microsatellite classes were identified. The popular Thai jasmine rice, KDML105, contained the (CT)17 repeats in the wx locus. Moreover, the (CT)17 repeat is the predominant class of the strains tested, whereas the (CT)11 class associated with high-amylose strains. In addition, a unique microsatellite class, (CT)18, was detected in some traditional glutinous strains and glutinous wild rice collected from the northeastern region.The restriction pattern of polymerase chain reaction-amplified Waxy DNA digested with AccI was also characterized. Polymorphism was observed between rice strains with low amylose and intermediate and high amylose content.

Keywords

• Oryza sativa
• Waxy microsatellite
• Waxy gene
• amylose