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.