Prosystemin Overexpression in Tomato Enhances Resistance to Different Biotic Stresses by Activating Genes of Multiple Signaling Pathways.
Systemin is a signal peptide that promotes the response to wounding and herbivore attack in tomato. This 18-amino acid peptide is released from a larger precursor, prosystemin. To study the role of systemin as a modulator of defense signaling, we generated tomato (Solanum lycopersicum) transgenic plants that overexpress the prosystemin cDNA. We carried out a transcriptomic analysis comparing two different transgenic events with the untransformed control. The Gene Ontology categories of the 503 differentially expressed genes indicated that several biological functions were affected. Systemin promotes the expression of an array of defense genes that are dependent on different signaling pathways and it downregulates genes connected with carbon fixation and carbohydrate metabolism. These alterations present a degree of overlap with the response programs that are classically associated to pathogen defense or abiotic stress protection, implying that end products of the systemin signaling pathway may be more diverse than expected. We show also that the observed transcriptional modifications have a relevant functional outcome, since transgenic lines were more resistant against very different biotic stressors such as aphids (Macrosiphum euphorbiae), phytopathogenic fungi (Botrytis cinereaandAlternaria alternata) and phytophagous larvae (Spodoptera littoralis). Our work demonstrated that in tomato the modulation of a single gene is sufficient to provide a wide resistance against stress by boosting endogenous defense pathways. Overall, the data provided evidence that the systemin peptide might serve as DAMP signal in tomato, acting as a broad indicator of tissue integrity.
Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, NA Italy.
Mariangela
M
Coppola
Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, NA Italy.
Giandomenico
G
Corrado
Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, NA Italy.
Valentina
V
Coppola
Institute for Plant Protection (CNR), 80055 Portici, NA Italy.
Pasquale
P
Cascone
CEINGE, 80145 Naples, Italy.
Rosanna
R
Martinelli
Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, NA Italy.
Maria Cristina
MC
Digilio
Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, NA Italy.
Francesco
F
Pennacchio
Dipartimento di Agraria, Università degli Studi di Napoli Federico II, 80055 Portici, NA Italy.
Rosa
R
Rao
DAMP; Defense; Resistance; Solanum lycopersicum; Systemin