XVI International Botanical Congess

D Senescence is a controlled degenerative process leading to death of whole plant, organ, tissue or cell. 7 of 9 gene clones previously shown to be up-regulated in senescing soybean cotyledons were used to examine expression patterns in soybean leaves in three situations where leaf senescence is modified, genetically defined evergreen mutants, manually depodded plants, and male sterile mutants. The differential expression patterns of 2 clones suggest that the regulation of these genes is not identical in cotyledons and leaf. The differential expression patterns of all 7 clones in response to depodding, male sterility and genetic backgrounds that produce an evergreen phenotype suggest that factors involved in pod formation and seed development directly affect the expression of senescence-related genes. These results indicate complex regulatory circuitry for gene expression during senescence.