Expression of a pathogen-induced gene can be mimicked by auxin insensitivity

Following perception of a pathogenic attack, plants are able to develop a s trong response with the corresponding activation of a plethora of defense-r elated genes, In this study we have characterized the mode of expression of the CEVI-1 gene from tomato plants, which encodes an anionic peroxidase, C EVI-1 expression is induced during the course of compatible viral and subvi ral infections, like many other defense-related genes, but is induced neith er in incompatible interactions nor by signal molecules such as salicylic a cid, ethylene, or methyl jasmonate, Additionally, CEVI-1 is induced in deta ched leaf tissues following a pathway distinct from that related to the cla ssical wound response, We also describe the characterization of the structu ral CEVI-1 gene and compare the mode of expression in different transgenic plant species harboring a CEVI-1::GUS construct. Furthermore, we have isola ted mutants in Arabidopsis, called dth mutants, that are deregulated in the control of expression of this gene, From the initial analysis of some of t hese mutants it seems that activation of CEVI-1 gene expression correlates with a defect in the perception of auxins by the plant, All these results m ay suggest that, during systemic infections with viruses, auxin homeostasis is one of the components participating in the regulation of the overall de fense response.