Isolation of fruit ripening genes from Carica papaya var. Eksotika 1 cDNA libraries

S. Yun Shin, S. Johari, V. Maheswary and A.B. Umi Kalsom

Abstract

As an initiative to discover genes that are associated with the fruit ripening process, the expressed sequence tags (ESTs) analysis was conducted on the local papaya variety Eksotika I. Single pass sequencing was performed on a total of 2,150 ESTs from early ripe and ripe Carica papaya var. Eksotika I cDNA libraries. Homology search on ESTs with BLASTX algorithm against Swiss-Prot non-redundant amino acid database revealed 71.1% of the papaya ESTs sequences matched the registered proteins with a cut off value of 1 x 10E-5. Analysis of KEGG and UniProt showed that there were 129 transcripts or 22 unigenes involved in fruit ripening processes such as ethylene biosynthesis pathway, fruit softening and aroma. The ESTs profiling data revealed a general picture of papaya gene expression and regulation pattern particularly of genes related to fruit ripening. The results obtained in this study can facilitate the follow up on gene expression studies using DNA microarray and contribute to the development of new markers for comparative and functional genomics studies of other tropical fruit crops.

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