Abundant mRNAs specific to the developing cotton fibres

Abstract

Five fibre-specific cDNA clones were isolated by differential screening of a cDNA library from cotton fibres, a developmentally synchronous population of non-dividing cells. The genes corresponding to these cDNAs were expressed preferentially in fibre cells and exhibited differing patterns of temporal expression during fibre development. One cDNA encoded a lipid transfer protein (LTP), and a second encoded a member of a group of well-characterised proline-rich proteins (PRP) from plants. The presence of signal peptide-encoding sequences suggests that both the LTP and the PRP are targeted to the extracellular matrix of the fibre, and a role is envisaged for each in cell elongation. Sequence analysis showed that a third clone was similar to a previously reported fibre-specific sequence of unknown function, whilst the remaining two cDNA clones showed no sequence similarity to previously reported plant nucleic acids.