COMPARATIVE-STUDY OF CELLULASES ASSOCIATED WITH ADVENTITIOUS ROOT INITIATION, APICAL BUDS, AND LEAF, FLOWER, AND POD ABSCISSION ZONES IN SOYBEAN

Cellulase activity was measured in soybean (Glycine max) leaf abscissi on zones, flower abscission zones, pod abscission zones, apical buds, and adventitious rooting hypocotyls. Immunoprecipitation data showed t hat a cellulase immunologically similar to the bean abscission cellula se (isoelectric point 9.5) is present in soybean leaf, flower, and pod abscission zones, but is not present in soybean apical buds or rootin g hypocotyls. cDNA and genomic clones for two different soybean genes were identified and show sequence similarity with the bean abscission cellulase clone pBAC10. The cDNA clone pSAC1, isolated from a soybean abscission cDNA library, hybridized to transcripts in soybean leaf, fl ower, and pod abscission zones. Although ethylene has been shown to pl ay a role in the increase in cellulase activity associated with both a bscission and adventitious root initiation, no signal was seen for hyb ridization of the soybean abscission cellulase clone, pSAC1, to RNA fr om soybean adventitious rooting hypocotyls. In addition, no soybean ab scission cellulase transcripts were detected in apical buds. Transcrip ts for a second soybean cellulase gene (SC2) were not detected in any of the tissues surveyed.