Identification of simple sequence repeats in rubber (Hevea brasiliensis)

摘要

The present study was undertaken to identify simple sequence repeats (SSRs) or microsatellites in Hevea, an important tree crop producing latex of commercial utility. A small-insert genomic library of Hevea, derived from a clone GT1, was screened forthe presence of SSRs (AC/TG and CT/GA motifs) and finally 154 clones were recovered. PCR amplification with vector-directed primers as well as with the repeat sequences confirmed 114 positive clones. Restriction analyses of the clones identified six duplicates and were thus eliminated. Fifty positive clones out of 108 were sequenced. Similarly, a large-insert genomic library, derived from a popular clone RRII105, was also screened and 24 positive clones were sequenced to validate the presence of microsatellites in the Hevea genome. Sequence data revealed the presence of 67 microsatellites having characteristic simple and compound repeats, out of which 59 were from GT1 and eight from RRII105. Different types of repeat motifs comprising dinucleo-tides (TG/AC, AG/TC, TA/AT), trinucleotides (AAG, AGG, ATT), tetranucleotides (GAAA, AAGG, ATCC, TAAA, AAAT) and one pentanucleotide (GAAAT) were detected. The abundance of CT/GA repeats as observed in Hevea genome was akin to those reported in other crops.