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Expression of C aenorhabditis elegans PCS in the AtPCS 1‐deficient A rabidopsis thaliana cad1‐3 mutant separates the metal tolerance and non‐host resistance functions of phytochelatin synthases
Author(s) -
Kühnlenz Tanja,
Westphal Lore,
Schmidt Holger,
Scheel Dierk,
Clemens Stephan
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12534
Subject(s) - phytochelatin , mutant , biology , glutathione , function (biology) , arabidopsis thaliana , caenorhabditis elegans , gene , biochemistry , microbiology and biotechnology , enzyme , genetics
Phytochelatin synthases ( PCS ) play key roles in plant metal tolerance. They synthesize small metal‐binding peptides, phytochelatins, under conditions of metal excess. Respective mutants are strongly cadmium and arsenic hypersensitive. However, their ubiquitous presence and constitutive expression had long suggested a more general function of PCS besides metal detoxification. Indeed, phytochelatin synthase1 from A rabidopsis thaliana ( AtPCS 1) was later implicated in non‐host resistance. The two different physiological functions may be attributable to the two distinct catalytic activities demonstrated for AtPCS 1, that is the dipeptidyl transfer onto an acceptor molecule in phytochelatin synthesis, and the proteolytic deglycylation of glutathione conjugates. In order to test this hypothesis and to possibly separate the two biological roles, we expressed a phylogenetically distant PCS from C aenorhabditis elegans in an AtPCS 1 mutant. We confirmed the involvement of AtPCS 1 in non‐host resistance by showing that plants lacking the functional gene develop a strong cell death phenotype when inoculated with the potato pathogen P hytophthora infestans . Furthermore, we found that the C . elegans gene rescues phytochelatin synthesis and cadmium tolerance, but not the defect in non‐host resistance. This strongly suggests that the second enzymatic function of AtPCS1, which remains to be defined in detail, is underlying the plant immunity function.