GERMINATION-ASSOCIATED LIPOXYGENASE TRANSCRIPTS PERSIST IN MATURING SOYBEAN PLANTS AND ARE INDUCED BY JASMONATE

Full-length and nearly full-length cDNA clones for the two major lipox ygenase (LOX) transcripts in the axis of germinating minating soybean (Glycine max [L.] Merr.) represent transcripts distinct from those of the three seed LOX isozymes. Gene-specific probes revealed that the se edling axis LOX transcripts were absent in developing embryos, while s eed LOX-3 transcripts did not accumulate in seedlings or in vegetative tissues. Seedling transcripts appeared in axes between 8 and 16 h aft er the start of imbibition (seeds germinated 24 h after the start of i mbibition) and reached maximal levels at 32 h. One seedling transcript (pTK18) was found in all non-embryonic tissues examined: axes and roo ts and leaves of two-week plants; the second transcript (pTK11) was al so found in vegetative tissues but in reduced levers when compared to pTK18, especially in the leaf Both transcripts were elevated by methyl jasmonate (MeJA) in the seedling. Thus, gene-specific probes allowed us to monitor the accumulation of two specific LOX transcripts under a variety of developmental and environmental conditions. Their accumula tion in the seedling, persistence in vegetative tissues and their dedu ced consensus signal peptide sequences make them candidates for the Me JA-induced vacuolar vegetative storage protein LOXs. This identificati on awaits employing gene-specific LOX probes on wounded tissues and th ose from plants grown under nitrogen excess/deficiency and under water stress.