Oil palm is grown in tropical soils with low bioavailability of Pi. A cDNA clone specifically expressed under phosphate-starvation condition in oil palm roots was identified as a high-affinity phosphate transporter (EgPHT1). The deduced amino acid sequence has 6 transmembrane domains each at the N- and C-termini separated by a hydrophilic linker. Comparison of promoter motifs within 1500 bp upstream of ATG of 10 promoters from high- and low-affinity phosphate transporter from both dicots and monocots including EgPHT1 was performed. The EgPHT1 promoter was fused to β-glucuronidase (GUS) reporter gene and its activity was analysed by histochemical and fluorometric GUS assays in transiently transformed oil palm tissues and T3 homozygous transgenic Arabidopsis plants. In response to Pi-starvation, no GUS activity was detected in oil palm leaves, but a strong inducible activity was observed in the roots (1.4 times higher than the CaMV35S promoter). GUS was specifically expressed in transgenic Arabidopsis roots under Pi deficiency and starvation of the other macronutrients (N and K) did not induce GUS activity. Eight motifs including ABRERATCAL (abscisic-acid responsive), RHERPATEXPA7 (root hair-specific), SURECOREATSULTR11 (sulfur-deficiency response), LTRECOREATCOR15 (temperature-stress response), MYB2CONSENSUSAT and ACGTATERD1 (water-stress response) as well as two novel motifs, 3 (TAAAAAAA) and 26 (TTTTATGT) identified through pattern discovery, occur at significantly higher frequency (p
Enroute to mapping QTLs for yield components in oil palm, we constructed the linkage map of a FELDA high yielding oil palm (Elaeis guineensis), hybrid cross. The parents of the mapping population are a Deli dura and a pisifera of Yangambi origin. The cross out-yielded the average by 8-21% in four trials all of which yielded comparably to the best current commercial planting materials. The higher yield derived from a higher fruit oil content. SSR markers in the public domain - from CIRAD and MPOB, as well as some developed in FELDA - were used for the mapping, augmented by locally-designed AFLP markers. The female parent linkage map comprised 317 marker loci and the male parent map 331 loci, both in 16 linkage groups each. The number of markers per group ranged from 8-47 in the former and 12-40 in the latter. The integrated map was 2,247.5 cM long and included 479 markers and 168 anchor points. The number of markers per linkage group was 15-57, the average being 29, and the average map density 4.7 cM. The linkage groups ranged in length from 77.5 cM to 223.7 cM, with an average of 137 cM. The map is currently being validated against a closely related population and also being expanded to include yield related QTLs.