Suppressors of systemin signaling identify genes in the tomato wound response pathway.
نویسندگان
چکیده
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).
منابع مشابه
The systemin signaling pathway: differential activation of plant defensive genes.
Systemin, an 18-amino-acid polypeptide released from wound sites on tomato leaves caused by insects or other mechanical damage, systemically regulates the activation of over 20 defensive genes in tomato plants in response to herbivore and pathogen attacks. Systemin is processed from a larger prohormone protein, called prosystemin, by proteolytic cleavages. However, prosystemin lacks a signal se...
متن کاملGenetic analysis of wound signaling in tomato. Evidence for a dual role of jasmonic acid in defense and female fertility.
Genetic analysis of the wound response pathway in tomato (Lycopersicon esculentum) indicates that prosystemin and systemin are upstream components of a defensive signaling cascade that involves complex regulation of jasmonic acid (JA) biosynthesis and the ability of cells to perceive and respond to JA. Recent identification of JA response mutants provides evidence for the hypothesis that the JA...
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Wound-induced systemic expression of defensive proteinase inhibitor (PI) genes in tomato plants requires the action of systemin and its precursor protein prosystemin. Although it is well established that systemin induces PI expression through the octadecanoid pathway for jasmonic acid (JA) biosynthesis, relatively little is known about how systemin and JA interact to promote long-distance signa...
متن کاملScientific Correspondence Genetic Analysis of Wound Signaling in Tomato. Evidence for a Dual Role of Jasmonic Acid in Defense and Female Fertility
Genetic analysis of the wound response pathway in tomato (Lycopersicon esculentum) indicates that prosystemin and systemin are upstream components of a defensive signaling cascade that involves complex regulation of jasmonic acid (JA) biosynthesis and the ability of cells to perceive and respond to JA. Recent identification of JA response mutants provides evidence for the hypothesis that the JA...
متن کاملPolypeptide signaling for plant defensive genes exhibits analogies to defense signaling in animals.
The activation of plant defensive genes in leaves of tomato plants in response to herbivore damage or mechanical wounding is mediated by a mobile 18-amino acid polypeptide signal called systemin. Systemin is derived from a larger, 200-amino acid precursor called prosystemin, similar to polypeptide hormones and soluble growth factors in animals. Systemin activates a lipid-based signaling cascade...
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ورودعنوان ژورنال:
- Genetics
دوره 153 3 شماره
صفحات -
تاریخ انتشار 1999