Normalized embryoid cDNA library of oil palm (Elaeis guineensis)

Pek-Lan Chan¹
Advanced Biotechnology and Breeding Centre
Malaysian Palm Oil Board
No. 6, Persiaran Institusi
Bandar Baru Bangi
43000 Kajang, Selangor, Malaysia

Lay-Sun Ma¹
Academia Sinica, 128 Sec. 2
Academia Rd, Nankang
Taipei 115, Taiwan-Republic of China

Eng-Ti L. Low¹
Advanced Biotechnology and Breeding Centre
Malaysian Palm Oil Board
No. 6, Persiaran Institusi
Bandar Baru Bangi
43000 Kajang, Selangor, Malaysia

Elyana M. Shariff
Myagri Associates Sdn Bhd
25-2, Jalan Seri Putra ½
Bandar Seri Putra Bangi
43000 Kajang, Selangor, Malaysia

Leslie Cheng-Li Ooi
Advanced Biotechnology and Breeding Centre
Malaysian Palm Oil Board
No. 6, Persiaran Institusi
Bandar Baru Bangi
43000 Kajang, Selangor, Malaysia

Suan-Choo Cheah
ACGT Sdn Bhd
Lot L3-I-1, Enterprise 4
Technology Park Malaysia, Bukit Jalil
57000 Kuala Lumpur, Malaysia

Rajinder Singh*
Advanced Biotechnology and Breeding Centre
Malaysian Palm Oil Board
No. 6, Persiaran Institusi
Bandar Baru Bangi
43000 Kajang, Selangor, Malaysia
E-mail: rajinder@mpob.gov.my

*Corresponding author

Financial support: Ministry of Science, Technology and Innovation (MOSTI), Malaysia under the Malaysia-MIT Biotechnology Partnership Programme (MMBPP).

Keywords: auxin, expressed sequence tags, gene expression, low abundance genes, tissue culture.

Note: The sequences have been deposited in GenBank. Accession numbers: DW247764-DW248770.

¹ These authors contributed equally to this work.

A normalized embryoid cDNA library (EON) was constructed based on reassociation kinetics reaction. Results from dot blot hybridization and sequencing of EON cDNA clones clearly indicated that the normalization process reduced the frequency of high abundance transcripts and increased the frequency of low abundance gene transcripts. A total of 553 non-redundant expressed sequence tags (ESTs) were identified, 325 of these were not observed in the standard oil palm cDNA libraries sequenced previously. A total of 10 EON cDNA clones were chosen for expression profiling across samples from different stages of the tissue culture process. Two of the genes exhibited promising expression patterns for predicting the embryogenic potential in callus. Some of these genes were also differentially expressed in the various tissues of oil palm. This study showed that normalization of the existing embryoid library improved the chances of identifying transcripts not captured in the standard libraries, some of which could be associated with embryogenesis. This collection of ESTs is particularly well suited for use as candidate genes for development of an oil palm DNA chip, which can be used to obtain a more comprehensive view of the molecular mechanism associated with oil palm tissue culture.