Differential Expression of Two Soybean (Glycine max L.) Proline-Rich Protein Genes after Wounding

We have investigated the wound-induced expression of two members of the soybean (Glycine max L.) proline-rich cell wall protein gene family and show that SbPRP1 and SbPRP2 exhibit unique patterns of expression after physical damage. SbPRP1 mRNA can be detected in the hook of soybean seedlings within 2 h after wounding and is present at high levels in the hook and elongating hypocotyl 20 h after wounding. In contrast, SbPRP2 mRNA increases transiently and rapidly throughout the soybean seedling after wounding. SbPRP2 is also induced by wounding in soybean leaves, but the pattern of mRNA accumulation in leaves is distinct from that seen in seedlings and reaches high levels of expression 20 h after physical damage. SbPRP2 mRNA levels were also found to increase in the mature hypocotyl and roots of seedlings in response to treatment with 10 [mu]M indoleacetic acid and naphthalene-1-acetic acid. These data indicate that the wound-induced expression of PRPs in soybean is tissue specific and that the regulation of these genes after physical damage may operate through different signal transduction pathways.