Identification of genes possibly related to storage root induction in sweetpotato

Abstract

To identify genes related to initiation of storage root development in sweetpotato, a cDNA library was constructed with early stage storage roots (0.3-1 cm in diameter). Single-pass sequences of the 5′ ends of 2859 sweetpotato cDNA clones were assembled into 483 clusters and 442 singletons. Comparison of sweetpotato expressed sequence tags (ESTs) to nodulation/tumorigenesis-related sequence databases (nodule-, tumor-, potato tuber- and development-related sequences) revealed that homologs of 39 sweetpotato EST sequences potentially involved in gene regulation, signal transduction and development were present in at least one of the nodulation/tumorigenesis-related sequence databases. Northern blot analyses of these 39 sequences identified 22 differentially expressed genes in early stage storage root and fibrous root. These differentially expressed genes will be potential candidates for research to elucidate the molecular processes related to sweetpotato storage root induction.