SSR markers in transcripts of genes linked to post-transcriptional and transcriptional regulatory functions during vegetative and reproductive development of Elaeis guineensis.
BACKGROUND
The oil palm (Elaeis guineensis Jacq.) is a perennial monocotyledonous tropical crop species that is now the world's number one source of edible vegetable oil, and the richest dietary source of provitamin A. While new elite genotypes from traditional breeding programs provide steady yield increases, the long selection cycle (10-12 years) and the large areas required to cultivate oil palm make genetic improvement slow and labor intensive. Molecular breeding programs have the potential to make significant impacts on the rate of genetic improvement but the limited molecular resources, in particular the lack of molecular markers for agronomic traits of interest, restrict the application of molecular breeding schemes for oil palm.


RESULTS
In the current study, 6,103 non-redundant ESTs derived from cDNA libraries of developing vegetative and reproductive tissues were annotated and searched for simple sequence repeats (SSRs). Primer pairs from sequences flanking 289 EST-SSRs were tested to detect polymorphisms in elite breeding parents and their crosses. 230 of these amplified PCR products, 88 of which were polymorphic within the breeding material tested. A detailed analysis and annotation of the EST-SSRs revealed the locations of the polymorphisms within the transcripts, and that the main functional category was related to transcription and post-transcriptional regulation. Indeed, SSR polymorphisms were found in sequences encoding AP2-like, bZIP, zinc finger, MADS-box, and NAC-like transcription factors in addition to other transcriptional regulatory proteins and several RNA interacting proteins.


CONCLUSIONS
The identification of new EST-SSRs that detect polymorphisms in elite breeding material provides tools for molecular breeding strategies. The identification of SSRs within transcripts, in particular those that encode proteins involved in transcriptional and post-transcriptional regulation, will allow insight into the functional roles of these proteins by studying the phenotypic traits that cosegregate with these markers. Finally, the oil palm EST-SSRs derived from vegetative and reproductive development will be useful for studies on the evolution of the functional diversity within the palm family.
IRD, UMR DIADE (IRD, UM2), 911 Avenue Agropolis BP 64501, 34394, Montpellier cedex 5, France. timothy.tranbarger@ird.fr
Timothy John
TJ
Tranbarger
Wanwisa
W
Kluabmongkol
Duangjai
D
Sangsrakru
Fabienne
F
Morcillo
James W
JW
Tregear
Somvong
S
Tragoonrung
Norbert
N
Billotte
D028023:Arecaceae / Q000235:genetics*; D001947:Breeding; D017931:DNA Primers / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D005819:Genetic Markers; D018745:Genome, Plant; D005838:Genotype; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012323:RNA Processing, Post-Transcriptional; D014158:Transcription, Genetic
D017931:DNA Primers; D018744:DNA, Plant; D005819:Genetic Markers