Wound-induced proteins

In tomato and potato plants, two families of Pis have been identified that show wound-inducible expression. Within 48 h after wounding of leaves of these plants, up to 2% of leaf protein content is made up of protease inhibitors. Potato type I (Potl) inhibitors are not only expressed in wounded leaves but also in tissue of leaves away from the site of attack. ° This finding prompted the search for a hormone or inducing factor that carries the signal for enhanced inhibitor expression through the plant system. Systemin, an 18-residue peptide hormone, has since been reported to induce more than 15 genes of defense nature in tomatoes. ... 

Chen, H.C., Klein, A., Xiang, M.H., Backhaus, R.A. and Kuntz, M. (1998) Drought and wound induced expression in leaves of a gene encoding a chromoplast carotenoid associated protein. Plant Journal 14(3), 317-326. 

TAIPALENSUU, J., ANDREASSON, E ERIKSSON, S., RASK, L Regulation of the wound-induced myrosinase-associated protein transcript in Brassica napus plants., Eur. J. Biochem., 1997,247,963-971. 

In addition to the PRPs outlined above, plants elaborate a variety of other defensive proteins (of which some are constitutive and others also induced by wounding) including protein inhibitors of ct-amylase, chitinase, polygalacturonase and of other glycosidases (Chapter 13) ... 

Cys-rich protein) Lycopersicon PI-II Lycopersicon esculentum CHY, TRY [wound induced]... 

In 1971, using the auxin-induced ethylene-producing system of mung bean hypocotyls, Sakai and Imaseki [70] proposed that auxin induces a protein essential to ethylene formation and that the protein is rapidly inactivated with an apparent half-life of 35 min. A similar result was obtained with pea epicotyls [71]. The short-lived essential protein was later identified as ACC synthase [32,72,73]. Wound-induced ACC synthase of tomato fmits is also inactivated but with a slightly longer half-life (30-100 min) [74]. 

Fig. 6. Effects of C-terminal deletion of CM-ACSI on enzyme activity. A series of 3 -deletion mutants were prepared from cDNA for the wound-induced ACC synthase from winter squash as shown in solid bars. Numbers of the deletion mutants are same to the number of amino acid residues deleted from C-terminus. Activities of enzymes produced by the transformed E. coli were assayed and amounts of enzyme protein were estimated by ELISA. Relative specific activities of each mutant proteins are plotted against the nucleotide sequence. Amino acid sequence at the critical junction is also shown.

There are different strategies that at least in theory should slow down the development of insect resistance in Bt plants [104, 105], including tissue-specific Bt protein expression (protecting only the critical tissues), wound-induced Bt protein expression (if expression would only be induced at a threshold level of insect... 

When methyl jasmonate was applied to the surface of tomato plants, the synthesis of a defensive proteinase inhibitor protein was induced, not only in the plant to which the application was made but also in nearby plants. In subsequent studies, this compound was shown to have a similar effect with plants of other families as well (Farmer and Ryan, 1990 Pearce et al., 1991). In a series of experiments, it was demonstrated that methyl jasmonate can be a component of interplant communication systems. Octadecanoid precursors of jasmonic acid were able to activate the synthesis of wound-inducible proteinase inhibitors (Crombie and Mistry, 1991 Farmer and Ryan, 1992). Jasmonic acid is a signal transducer in elicitor-induced plant cultures of Rauvolfia canescens and Eschscholtzia californica. Tissue cultures of 36 species of plants could be induced to accumulate second-... 

Pearce, G., D. Strydom, S. Johnson, and C. A. Ryan, A polypeptide from tomato leaves induces wound-inducible proteinase inhibitor proteins. Science, 253, 895-898 (1991). 

Involvement of cytokinin in wound responses has been observed [198]. Production of wound-inducible jasmonic acid in tobacco plants was observed earlier in the presence of cytokinin than in its absence. High levels of cytokinin also induce salicylic acid accumulation in wounded tobacco leaves. Accumulation of high levels of jasmonic acid and salicylic acid in wounded tissue in the presence of cytokinin corresponds with the expression of basic and acidic pathogenesis-related proteins, respectively. These results indicate that cytokinins are indispensable for control of endogenous levels of both salicylic and jasmonic acids. 

Harms et al. [197] produced transgenic potato plants overexpressing a flax allene oxide synthase gene. These plants accumulated allene oxide synthase proteins in chloroplasts and accumulated jasmonic acid in levels equivalent to or higher than the wound-induced levels in control plants, but did not accumulate pin 2. The authors speculated that the reason for the lack of pin 2 expression might be involvement of a cytosolic LOX/allene oxide synthase pathway in pin 2 induction or sequestration of jasmonic acid in chloroplasts or peroxisomes in allene oxide synthase transgenic plants, but not wounded plants. Creelman and Mullet [29]... 

We have obtained a cDNA clone of the wound-induced enzyme by screening a cDNA library constructed in an expression vector, pTTQlS, with the antibody. Size of the insert DNA in the clone (pCMW33) was 1.8 kbp, and the transformant bacteria harboring this plasmid produced under the inductive conditions protein of about 58 kDa exhibiting ACC synthase activity. Northern blot analysis of RNA obtained from incubated mesocarp slices with the insert DNA as a probe showed that mRNA for ACC synthase was of 1.9 kb. This mRNA was not detected in fresh tissue, but increased after wounding (unpublished results). 

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