Abstract
A total of 2414 new di-, tri- and tetra-nucleotide non-redundant SSR primer pairs, representing
2240 unique marker loci, have been developed and experimentally validated for rice (Oryza sativa L.).
Duplicate primer pairs are reported for 7% (174) of the loci. The majority (92%) of primer pairs were
developed in regions flanking perfect repeats ≥ 24 bp in length. Using electronic PCR (e-PCR) to align
primer pairs against 3284 publicly sequenced rice BAC and PAC clones (representing about 83% of the
total rice genome), 65% of the SSR markers hit a BAC or PAC clone containing at least one genetically
mapped marker and could be mapped by proxy. Additional information based on genetic mapping and
“nearest marker” information provided the basis for locating a total of 1825 (81%) of the newly designed
markers along rice chromosomes. Fifty-six SSR markers (2.8%) hit BAC clones on two or more different
chromosomes and appeared to be multiple copy. The largest proportion of SSRs in this data set correspond
to poly(GA) motifs (36%), followed by poly(AT) (15%) and poly(CCG) (8%) motifs. AT-rich microsatellites
had the longest average repeat tracts, while GC-rich motifs were the shortest. In combination with
the pool of 500 previously mapped SSR markers, this release makes available a total of 2740 experimentally
confirmed SSR markers for rice, or approximately one SSR every 157 kb.
Key words: simple sequence repeats (SSR); rice (Oryza sativa L.); electronic PCR (e-PCR)