Introduction:
The
sequencing of the full nuclear genome of sesame (Sesamum indicum
L.) provides the platform for functional analyses of genome components
and their application in breeding programs. Although the importance of
microsatellites markers or Simple Sequence Repeats (SSR) in crop
genotyping, genetics and breeding applications is well established, only
a little information exist concerning SSRs at the whole genome level in
sesame. In addition, SSRs represent a suitable marker type for sesame
molecular breeding in developing countries where it is mainly grown. In
this study, we identified 138,194 genome-wide SSRs of which 76.5% were
physically mapped onto the 13 pseudo-chromosomes. Among these SSRs, up
to 3 primers pairs were supplied for 101,930 SSRs and used to in
silico amplify the reference genome together with two newly
sequenced sesame accessions. A total of 79,957 SSRs (78%) were
polymorphic between the 3 genomes thereby suggesting their promising use
in different genomics-assisted breeding applications. From these
polymorphic SSRs, 23 were selected and validated to have high
polymorphic potential in 48 sesame accessions from different growing
areas of Africa. Furthermore, we have developed an online user-friendly
database, SisatBase (http://www.sesame-bioinfo.org/SisatBase/), which
provides free access to SSRs data as well as an integrated platform for
functional analyses. Altogether, the reference SSR and SisatBase would
serve as useful resources for genetic assessment, genomic studies and
breeding advancement in sesame, especially in developing countries.
|
 |
SSR Mining |
Total |
|
Total number of sequence scaffolds examined |
4,449 |
|
Total number of identified SSRs |
138,194 |
|
Number of sequence scaffolds containing SSR |
1,279 |
|
Number of sequence scaffolds containing more than 1 SSR |
877 |
|
Number of compound SSRs |
28,666 |
|
Number of SSRs present in genic regions |
20,167 |
|
Repeat type |
Number of SSRs |
Percentage |
Mono-nucleotide |
67,949 |
49.17 |
Di-nucleotide |
59,886 |
43.33 |
Tri-nucleotide |
9,116 |
6.60 |
Tetra-nucleotide |
933 |
0.68 |
Penta-nucleotide |
148 |
0.11 |
Hexa-nucloetide |
162 |
0.12 |
Total |
138,194 |
100 |
|