Overexpression of the prosystemin gene in transgenic tomato plants generates a systemic signal that constitutively induces proteinase inhibitor synthesis.

Abstract

Tomato Tomato Transformation. The prosystemin expression construct was introduced into Agrobacterium tumefaciens strain LA 4404 and was used to transform tomato (var. Better Boy) cotyledon tissue as previously described (10).Grafting Experiments. Plants (Better Boy) were used 5-6 weeks after germination. The upper halves of the plants were excised at the midpoint of the stem and all the leaves were trimmed away with the exception of the pair of leaves immediately beneath the apical meristem. The cut ends ofthe stems were notched and grafting was accomplished by aligning the notched ends of the stems and wrapping the graft site with Parafilm. Grafted plants were enclosed in a transparent plastic bag in the laboratory for 4 or 5 days before being allowed to regenerate and grow in the greenhouse for 7-8 weeks. Senescent leaves on the lower half of each grafted plant were periodically removed, although the plants were left undisturbed for at least 1 week prior to assaying the levels of proteinase inhibitors. Wounding and Immunoiogical Assay of Proteinase Inhibitors. Wounding experiments utilized 14-to 16-day-old plants, which were wounded on the lower of the two primary leaves and left under constant illumination for 24 hr. The levels of proteinase inhibitor I and inhibitor II were measured as described (11,12).

A Gene Encoding a Chloroplast-Targeted Lipoxygenase in Tomato Leaves Is Transiently Induced by Wounding, Systemin, and Methyl Jasmonate

“…A phloem mobile polypeptide called systemin behaves as a systemic signal released from wound sites (Pearce et al, 1991;McGurl et al, 1992McGurl et al, , 1994Narvaez-Vasquez et al, 1995), but severa1 other chemicals, including IAA (Thornburg and Li, 1990), ABA (PeAa-Cortés et al, 1989), and ethylene (ODonnell et al, 1996), have been associated with the signaling pathway and with physical forces such as hydraulic effects (Malone and Alarcon, 1995) and action potentials (Herde et al, 1996;Rhodes et al, 1996;Stankovic and Davies, 1996).…”

“…The LOX 19 amino acid sequence exhibited 81% identity to the fruit-specific TomLOXA (Ferrie et al, 1994) and was not studied further. On the basis of sequence similarities with plant LOX sequences (see below), the Lox 6 and Lox 18 clones were chosen as probes to screen a cDNA library constructed from plants overexpressing a prosystemin transgene and overexpressing severa1 defense genes (McGurl et al, 1994;Schaller et al, 1995). We isolated full-length clones of 2807 and 3034 bp corresponding to Lox 6 and Lox 18, respectively, and these clones were called TomLoxC and TomLoxD, respectively.…”

“…Tomato (cv Better Boy) plants expressing a transgene consisting of a prosystemin cDNA under control of the cauliflower mosaic virus 35s promoter were as described by McGurl et al (1994) and were grown under the same conditions. For a11 experiments 12-to -15-d-old plants were used.…”

“…The 0.6-kb amplification product was purified with Prep-A-Gene matrix (Bio-Rad), reamplified in the same conditions, and cloned in the EcoRI site of pBluescript (Stratagene). The cDNA library was constructed with 5 pg of poly(A+) RNA from plants overexpressing a prosystemin transgene (McGurl et al, 1994). The cDNA was synthesized and ligated into the AZAP vector (Stratagene) according to the manufacturer's instructions.…”

Jasmonate-induced plant defenses and prey availability impact the preference and performance of an omnivorous stink bug, Podisus maculiventris

“…The level of plant resistance via the jasmonate pathway was manipulated using three types of tomato plants that vary in the inducibility of the jasmonate pathway. Wild-type tomato plants (Solanum lycopersicon cv Castlemart) that induce the jasmonate pathway following wounding, jasmonateinsensitive mutant plants [jai-1; (Li et al 2004)] that do not induce the JA pathway even when damaged and jasmonateoverexpressing 35S::prosystemin plants that express the jasmonic acid pathway constitutively (McGurl et al 1994). The jasmonate-insensitive plant is a mutant defective in jasmonate perception that was backcrossed two times into the Castlemart variety, and the jasmonate overexpressor is a transgenic plant developed using agrobacterium-mediated transformation and backcrossed into the Castlemart variety.…”