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Genetics

Title:		Suppressors of systemin signaling identify genes in the tomato wound response pathway
Author(s):		Howe GA; Ryan CA;
Address:		"Department of Energy Plant Research Laboratory and Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824, USA. howeg@pilot.msu.edu"
Journal Title:		Genetics
Year:		1999
Volume:		153
Issue:		3
Page Number:		1411 - 1421
DOI:		10.1093/genetics/153.3.1411
ISSN/ISBN:		0016-6731 (Print) 0016-6731 (Linking)
Abstract:		"In tomato plants, systemic induction of defense genes in response to herbivory or mechanical wounding is regulated by an 18-amino-acid peptide signal called systemin. Transgenic plants that overexpress prosystemin, the systemin precursor, from a 35S::prosystemin (35S::prosys) transgene exhibit constitutive expression of wound-inducible defense proteins including proteinase inhibitors and polyphenol oxidase. To study further the role of (pro)systemin in the wound response pathway, we isolated and characterized mutations that suppress 35S::prosys-mediated phenotypes. Ten recessive, extragenic suppressors were identified. Two of these define new alleles of def-1, a previously identified mutation that blocks both wound- and systemin-induced gene expression and renders plants susceptible to herbivory. The remaining mutants defined four loci designated Spr-1, Spr-2, Spr-3, and Spr-4 (for Suppressed in 35S::prosystemin-mediated responses). spr-3 and spr-4 mutants were not significantly affected in their response to either systemin or mechanical wounding. In contrast, spr-1 and spr-2 plants lacked systemic wound responses and were insensitive to systemin. These results confirm the function of (pro)systemin in the transduction of systemic wound signals and further establish that wounding, systemin, and 35S::prosys induce defensive gene expression through a common signaling pathway defined by at least three genes (Def-1, Spr-1, and Spr-2)"
Keywords:		"Catechol Oxidase/genetics Ethyl Methanesulfonate Gene Expression Regulation, Plant Genotype Solanum lycopersicum/*genetics/physiology Mutagenesis Peptides/*genetics/*metabolism Plant Proteins/genetics/metabolism Plants, Genetically Modified Protease Inhib;"
Notes:		"MedlineHowe, G A Ryan, C A eng F32GM16888/GM/NIGMS NIH HHS/ R01GM57795/GM/NIGMS NIH HHS/ Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. 1999/11/05 Genetics. 1999 Nov; 153(3):1411-21. doi: 10.1093/genetics/153.3.1411"