Isolation of flower-specific cDNA clones from sunflower

Abstract

Proteins from flower, leaves and roots of sunflower ( Helianthus annuus L.) have been resolved by two-dimensional polyacrylamide gel electrophoresis into distinctive patterns. A careful examination of these patterns reveals that many proteins are present in at least two of the three organs, but thateach of these organs has, in addition, a set of specific proteins. Following this observation we have used differential hybridization screening to isolate flower-specific cDNA clones from a sunflower floral cDNA library. Out of 31 clones originally isolated, 12 were subcloned and analyzed by Southern and Northern hybridization experiments. Four clones (SF1, SF2, SF6 and SF7) were shown to cross-hybridize, indicating that they carry the same (or a closely related) insert. Cross-hybridization was also found between clones SF9 and SF19. Using Northern hybridization with RNAs isolated from the individual floral parts we identified an anther-specific clone (SF18), two shown to hybridize to RNA from pistils, from anthers and, to a lesser extent, from corollae.