| Summary: | Makapuno is an abnormal coconut with characteristic endosperm overgrowth. It has softer, fluffy endosperm of normal coconut. To gain insights on the molecular basis of the makapuno phenomenon, ten selected genes were cloned, characterized, and their expression determined through Relative RT-PCR with actin as internal control gene. The ten genes showed conserved domains and have 75-98% identity to other plant sequences when analyzed with Interproscan and BLAST. Four of the ten genes were found to have lower expression in makapuno including an isopetanyl transferase gene that control the first rate-limiting step in cytokinin biosynthesis. Three glucolytic genes, cytosolic glycerldehyde-3-phosphate dehydrogenerase, cytosolic pyruvate kinase and enolase were also downregulated in makapuno. On the other hand, three regulatory genes namely, protein kinase CK2 regulatory subunit, polyA binding protein, myb-like transcription factor were upregulated in makapuno. There was also altered expression of pyruvate decarboxylase, á-D-galactosidase, and ketoacyl-acyl carrier protein synthase 1(KAS1). These data support previously reported differences in cytokinin levels, carbon metabolism and respiratory levels in the normal and makapuno coconut endosperms. These also provided further insights into the elucidation of the molecular mechanisms regulating gene expression in normal and makapuno endosperm of coconut.
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