Jasmonate-induced proteins in cotton: Immunological relationship to the respective barley proteins and homology of transcripts to late embryogenesis abundant (Lea) mRNAs

Abstract

(-)-Jasmonic acid methyl ester (Ja-Me) causes a drastic alteration of gene expression in excised cotton (Gossypium hirsutum L.) cotyledons. After in vivo labeling with L-[35S]methionine, soluble proteins of Ja-Me-treated cotyledonary segments were analyzed by two-dimensional polyacrylamide gel electrophoresis. Several different classes of polypeptides were observed, corresponding to molecular sizes of Mr 67, 40, 35, 30, 25, 23, 20, 18 kDa, which were absent in water-treated (control) segments. Western-blot analysis with antibodies raised against 66, 37, and 23 kDa jasmonate-induced proteins (JIPs) of barley (Herrmann et al. 1989) revealed that only the 23 kDa JIPs of cotton are immunologically related to those of barley. The Ja-Me-induced alteration in the protein pattern correlated with the appearance of novel in vitro translatable mRNAs which accumulated transiently or steadily during the incubation period. Three of the Ja-Me-induced mRNAs hybridized with a synthetic oligonucleotide probe that was complementary to a highly conserved sequence motif found in the cotton Lea (late embryogenesis abundant) gD-7 gene (Baker et al. 1988) and in some other Lea genes (Dure et al. 1989). The level of the 2.17, 1.46, and 0.71 kb transcripts detected at a melting temperature (Tm) — 15°C criterion did not change significantly in the water-control cotyledons, but they increased three- to fourfold in jasmonate-treated cotyledons.