Methyljasmonate-induced changes in the polypeptide pattern of senescing barley leaf segments

Gene expression during leaf senescence

“…Muller-Uri et al (1988) proposed that the protein synthesis induced by JA-Me is a cause rather than a consequence of senescence. However, cytokinins can cause regreening of leaf segments after JA-Me treatment, even though synthesis of jasmonate-induced proteins still occurs (Weidhase et al, 1987). The current view of Sembdner & Parthier (1993) is that jasmonates are part of the stress signal transduction pathway, rather than being a direct cause of senescence.…”

“…At present, there is scant information a\'aitable on this subject, and reports concentrate on the association between only a few components. For example, cytokinins have been shown to counteract jasmonate-induced senescence symptoms without pre\'enting the synthesis of jasmonate-induced proteins (Weidhase et al, 1987). Also, Bittman, Simpson & Mir (1988) reported that drought increased leaf senescence more in floral than non-fioral tillers of temperate forage grasses, suggesting an additive effect of external and internal factors which trigger senescence.…”

“…Methyl jasmonate (JA-Me) has been shown to pron:iote the senescence of excised oat lea\'es (Ueda & Kato, 1981). Treatment of barley leaf segments with 45 //M JA or JA-Me caused not only the acceleration of senescence but also the synthesis de no'vo of a numher of abundant proteins (Weidhase et al., 1987). The pattern of protein synthesis in vivo and in vitro appears to be virtually identical, suggesting that the mRNAs corresponding to these proteins are newly synthesized after treatment with JA-Me (Muller-Uri, Parthier & Nover, 1988).…”

JIPs and RIPs: the regulation of plant gene expression by jasmonates in response to environmental cues and pathogens.

“…One of the most remarkable effects of MeJA in barley is to repress the synthesis of most preexisting ("control") proteins (Weidhase et al, 1987a). Although the population of translatable control mRNAs, including nbcS and cab, is conserved in MeJA-treated barley leaf tissues for at least 24 hr, most of these mRNAs are no longer translated into protein in vivo (MullerUri et al, 1988;Reinbothe et al, 1993aReinbothe et al, , 1993b.…”

“…At least three major jasmonate effects have been reported to be exerted at the gene expression level: (1) the induction of nove1 abundant polypeptides, designated jasmonate-induced proteins (JIPs) (Parthier et al, 1987), (2) the selective repression of synthesis of severa1 polypeptides that are present before jasmonate or stress treatment (Weidhase et al, 1987a;Reinbothe et al, 1993aReinbothe et al, , 1993bReinbothe et al, , 1993c, and (3) the temporally delayed general downregulation of protein biosynthesis occurring in long-term MeJAtreated or long-term stressed leaf tissues (Reinbothe et al, 1994). Figure 1 illustrates the first two effects in the polypeptide patterns of MeJA-treated leaf tissues in plants as diverse as barley, Nicotiana plumbaginifolia, and Arabidopsis.…”