The terms thorns, prickles, and spines, often used synonymously, actually refer to very different structures in terms of both plant development and morphology. While thorns and spines are derived from secondary branch or leaf meristems and contain vasculature, prickles are simply outgrowths of epidermal, and sometimes cortical tissues. Thus, because of their structural simplicity, prickle development provides an ideal system to study how cells communicate to control growth, proliferation, and morphological differentiation of an anatomical structure – a fundamental aspect of all developmental pathways. To study this organ we have selected blackberries and raspberries, which have both prickled and prickleless varieties. Initial studies suggest that prickles either develop directly from glandular trichomes (raspberry) or these trichomes may provide a signal that allows proliferation of the underlying cortical cells (blackberry). To gain insight into the molecular control of these processes, we have created subtractive cDNA libraries from prickle-prickleless varieties of blackberry and raspberry. Additionally, we are currently analyzing gene candidates and characterizing their functional role in prickle development with which we hope to increase our understanding of the role trichomes may play in prickle development. This project was supported by a grant from the United States Department of Agriculture.
Kellogg, A. A.*, Branaman, T. J.*, Jones, N. M.**, Little, C. Z.*, Swanson, J-D. (2011) Morphological studies of developing Rubus prickles suggest that they are modified glandular trichomes. Botany 89:217-226
Thompson, M.*, Tippit, D.*, Hill, K.*, Magie, B.*, Kellogg, A.*, Little, C.*, Jones, N.**, Swanson, J-D., (2010), Investigating the Functional Roles of Genes Involved in Early, Middle, and Late Rubus Prickle Development. HortScience 45(8):S234. (Abstr.), poster presented at the ASHS Annual Conference, Palm Desert, CA. Aug 2-5, 2010. This poster won 2nd place in the Undergraduate competition
Kellogg, A.A.*, Parker, K.*, Swanson, J-D., (2009) Molecular Investigation of Early Prickle Development Genes in Rubus. Plant and Animal Genome Meeting XVII, San Diego, CA. Jan 10-14, 2009