Developmental and Structural Section
Kerr, Tyson C , Evans, Rodger C. .
Comparative MADS-box gene expression in Physocarpus opulifolius (Rosaceae).
Floral homeotic genes are involved in specifying the location and identity of floral organs in angiosperm flowers. These genes, the majority of which are MIKC-type MADS-box genes, fall in the middle of a hierarchy of genes responsible for floral development. The Rose family (Rosaceae) contains many commercially important species; however, the expression pattern of floral organ identity genes is still not clearly understood in the few Rosaceae taxa studied to date. This research seeks to determine expression patterns of B- and C-class MADS-box genes in Physocarpus opulifolius. Inflorescences at various stages of development were embedded in paraffin wax and thin-sectioned prior to in situ-hybridization probing with DIG-labelled Physocarpus opulifolius specific B- and C-class genes. B-class gene expression largely reflected that observed in previous studies of Rosaceae, however, two unexpected expression patterns were found. B-class genes exhibited tissue specific differential expression during anther development and ovule initiation. PI homologs were restricted to layers outside those involved in microsporogenesis, whereas euAP3 and TM6 homologs were confined to developing sporogenous tissues. All three B-class genes were found to be expressed in placental and ovule tissues. AG exhibited expression patterns similar to that observed in previous studies; in stamens, carpels and ovules. These findings indicate that the B-class genes, in addition to organ initiation in Rosaceae flowers, may be involved in development of female reproductive organs, as well as playing a role in microsporangium tissue differentiation.
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1 - Acadia University, Biology Department, 33 Westwood Ave, Wolfville, Nova Scotia, B4P 2R6, Canada
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Tuesday, July 28th, 2009
Time: 2:30 PM