Distribution of two transposon-like elements in rice

Abstract

We have previously identified two transposon-like elements, RTL-1 and RTL-2, by comparison of the Wx genes of cultivated Asian rice with that of Oryza L.f. spontanea. In this paper we report the distribution and organization of RTL-1 and RTL-2 in the genomes and Wx genes of the genus Oryza (AA, BB, BBCC, CC, CCDD, EE). Southern blot analyses indicate that RTL-1 and RTL-2 are interspersed in all AA genomes of wild rice examined. It is noteworthy that hybridization patterns and copy numbers of RTL-2 are different in some rice species. PCR amplifications using primers in exon regions flanking intron 10 or intron 13 indicate that neither RTL-1 nor RTL-2 is present in the corresponding site of the Wx genes of BB, BBCC, CC, CCDD, EE genome-type of rice. RTL-1 is only present in the Wx gene of O. nivara, O. rufipogon (Guangdong, crawl), while RTL-2 present in the corresponding site of Wx genes of all AA genome-type. Surprisingly we found and proved by sequence analysis that in O. rufipogon from Sri Lanka there are two bands (161 bp and 300 bp) corresponding to the excision/insertion of RTL-1. © 1993.