Comparative MADS-box gene expression in Physocarpus opulifolius (Rosaceae)
LE3 .A278 2009
2009
Evans, Rodger
Acadia University
Master of Science
Masters
Biology
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. 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, however, two unexpected expression patterns were found. B- class genes exhibited tissue specific differential expression in developing anthers, and were expressed in initiated ovules. PI homologs were restricted to layers outside those involved in microsporogenesis, but euAP3 and TM6 homologs were confined to developing sporogenous tissues. All three B- class genes were found to be expressed in developing placental and ovule tissue. AG exhibited expression patterns similar to that seen in previous studies; in the stamens, carpels and ovules. These findings indicate that the B- class genes may be involved in the development of the female reproductive organs, and, that they may play a role in tissue differentiation, in addition to organ initiation in Rosaceae flowers.
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https://scholar.acadiau.ca/islandora/object/theses:141