Schlaeppi, Klaus Bodenhausen, Natacha Buchala, Antony J. Mauch, Felix Reymond, Philippe 2008-05-08 Plants often respond to pathogen or insect attack by inducing the synthesis of toxic compounds such as phytoalexins and glucosinolates (GS). The Arabidopsis mutant pad2-1 has reduced levels of the phytoalexin camalexin and is known for its increased susceptibility to fungal and bacterial pathogens. We found that pad2-1 is also more susceptible to the generalist insect Spodoptera littoralis but not to the specialist Pieris brassicae. The PAD2 gene encodes a γ-glutamylcysteine synthetase that is involved in glutathione (GSH) synthesis, and consequently the pad2-1 mutant contains about 20% of the GSH found in wild-type plants. Lower GSH levels of pad2-1 were correlated with reduced accumulation of the two major indole and aliphatic GSs of Arabidopsis, indolyl-3-methyl-GS and 4-methylsulfinylbutyl-GS, in response to insect feeding. This effect was specific to GSH, was not complemented by treatment of pad2-1 with the strong reducing agent dithiothreitol, and was not observed with the ascorbate-deficient mutant vtc1-1. In contrast to the jasmonate-insensitive mutant coi1-1, expression of insect-regulated and GS biosynthesis genes was not affected in pad2-1. Our data suggest a crucial role for GSH in GS biosynthesis and insect resistance. application/pdf https://folia.unifr.ch/global/documents/300970 https://folia.unifr.ch/documents/300970/files/mauch_gdm.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-313X.2008.03545.x info:eu-repo/semantics/openAccess License undefined The Plant Journal. - 2008, vol. 55, no. 5, p. 774 - 786 info:eu-repo/classification/udc/57 The glutathione-deficient mutant pad2-1 accumulates lower amounts of glucosinolates and is more susceptible to the insect herbivore Spodoptera littoralis http://purl.org/coar/resource_type/c_6501