Differential Expression of Soybean Cysteine Proteinase Inhibitor Genes during Development and in Response to Wounding and Methyl Jasmonate

Abstract

Three cysteine proteinase inhibitor cDNA clones (pL1, pR1, and pN2) have been isolated from a soybean (Glycine max 1. Merr.) embryo library. The proteins encoded by the clones are between 60 and 70% identical and contain the consensus QxVxC motif and W residue i n the appropriate spatial context for interaction with the cysteine proteinase papain. L7, R7, and N2 mRNAs were differentially expressed in different organs of plants (juvenile and mature) and seedlings, although NZ mRNA was constitutive only i n flowers. R I and N2 transcripts were induced by wounding or methyl jasmonate (M-JA) treatment in local and systemic leaves coincident with increased papain inhibitory activity, indicating a role for R I and N2 in plant defense. The L I transcript was constitutively expressed in leaves and was induced slightly by M-JA treatment in roots. Unlike the chymotrypsin/trypsin proteinase inhibitor II gene (H. Peiia-Cortes, J. Fisahn, 1. Willmitzer [19951 Proc Natl Acad Sci USA 92: 41 06-41 13), expression of the soybean genes was only marginally induced by abscisic acid and only in certain tissues. Norbornadiene, a competitive inhibitor of ethylene binding, abolished the wounding or M-JA induction of R I and N2mRNAs but not the accumulation of the wound-inducible vspA transcript. Presumably, ethylene binding to its receptor is involved in the wound inducibility of R I and N2 but not vspA mRNAs. Bacterial recombinant L I and R1 proteins, expressed as glutathione S-transferase fusion proteins, exhibited substantial inhibitory activities against vicilin peptidohydrolase, the major thiol endopeptidase i n mung bean seedlings. Recombinant R I protein had much greater cysteine proteinase inhibitor activity than recombinant L I protein, consistent with the wound inducibility of the R7 gene and its presumed role in plant defense.Injury to plants due to phytophagous insects or mechanical damage induces accumulation of proteinase inhibitor proteins (Ryan, 1981(Ryan, , 1990. Inhibitor proteins with specificity against Ser proteinases have been well characterized and there is direct evidence of their involvement in host plant defense against herbivorous insects (Johnson et al.,

Anthropogenic increase in carbon dioxide compromises plant defense against invasive insects

“…The positive interaction between JA and ethylene after wounding synergistically induces PI genes, such as CystPI genes in soybean (14). However, changes in the synthesis of JA by elevated CO 2 can affect constitutive and inducible CystPI activity levels.…”

“…3). The potent inhibitory capacity and the effectiveness of these soybean CystPIs (N2 and R1) against many coleopteran species have been demonstrated by feeding experiments with plants or with diets containing recombinant inhibitors (13)(14)(15). CystPIs can affect the behavior and performance of adult coleopterans.…”

“…3) had very low papain and digestive cysteine proteinase inhibitor activity (13,14). In view of the fact that L1 CystPI was slightly induced in roots by MeJA (14), CystPI L1 may play a role in regulating cysteines involved in nodule senescence (29).…”

“…Soybean (Glycine max), the world's most widely grown seed legume, has one constitutive CystPI gene (L1) and two inducible CystPI genes (N2 and R1) (13,14). Soybean CystPIs, as well as the synthetic CystPI, transepoxysucciny-L-leucyl-amido (4-guanidino)…”

Digestive enzymes during development of Ceratitis capitata (Diptera:Tephritidae) and effects of SBTI on its digestive serine proteinase targets

“…Plant proteinase inhibitors, a-amylase inhibitors, lectins and chitin binding proteins are usually expressed in response to herbivore insects, pathogens and wounding (Ryan, 1990;Botella et al, 1996;Koiwa et al, 1997;Sales et al, 2001) and may affect development by interfering in the proteolytic processes of a wide range of potentially damaging organisms, including bacteria, fungi, nematodes (Haq et al, 2004) and insects (Terra and Ferreira, 1994;Pompermayer, et al, 2001;Falco and Silva-Filho, 2003). The effects on insects can be observed when digestive enzymes are inhibited or when defense proteins bind to the gut structures of larvae and insects (XavierFilho, 1993).…”