Isolation and preliminary characterization of tomato petal- and stamen-specific cDNAs from a subtracted and equilibrated cDNA library

Abstract

In order to study genes involved in latestages of flower development, we wereinterested in isolating petal- orstamen-specific genes, particularly onesexpressed at a low level, as they mayinclude regulatory genes. To this end, asubtracted and equalized cDNA library oftomato petals and stamens was constructed.Approximately 650 clones of this librarywere found to represent 84 different genes.Northern analyses performed on 43 clonesdemonstrated that 19 of them are specificto stamens, five are almost exclusivelyexpressed in petals, 17 clones arespecifically expressed in both petals andstamens, two are restricted to petals andyoung fruit, and only two are non-specific.Five of the organ-specific clones, and oneof the two non-specific clones showedsimilarity to various regulatory proteins.Seventeen of the unique flower-expressedsequences were not present in either EST orGenBank databases, indicating substantialenrichment of rare transcripts. Takentogether, it was demonstrated thatfollowing careful design of subtracted andequalized cDNA library it is feasible, atreasonable time and cost, to isolate asignificant number of novel petal- and/orstamen-specific cDNA clones, even intomato, a species on which a comprehensiveEST project is currently being performed.