Expression of a Pathogen-Induced Gene Can Be Mimicked by Auxin Insensitivity

Abstract

Following perception of a pathogenic attack, plants are able to develop a strong response with the corresponding activation of a plethora of defense-related genes. In this study we have characterized the mode of expression of the CEVI-1 gene from tomato plants, which encodes an anionic peroxidase. CEVI-1 expression is induced during the course of compatible viral and subviral infections, like many other defense-related genes, but is induced neither in incompatible interactions nor by signal molecules such as salicylic acid, ethylene, or methyl jasmonate. Additionally, CEVI-1 is induced in detached leaf tissues following a pathway distinct from that related to the classical wound response. We also describe the characterization of the structural CEVI-1 gene and compare the mode of expression in different transgenic plant species harboring a CEVI-1::GUS construct. Furthermore, we have isolated mutants in Arabidopsis, called dth mutants, that are deregulated in the control of expression of this gene. From the initial analysis of some of these 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 may suggest that, during systemic infections with viruses, auxin homeostasis is one of the components participating in the regulation of the overall defense response.

cDNA-AFLP analysis of gene expression changes in apple trees induced by phytoplasma infection during compatible interaction

“…Auxin homeostasis is one of the components participating in the regulation of the defence response (Mayda et al 2000). So, deregulation of auxin efflux carrier in this study suppresses the defence response pathways.…”

Arabidopsis dth9 Mutation Identifies a Gene Involved in Regulating Disease Susceptibility without Affecting Salicylic Acid–Dependent Responses

“…Additionally, CEVI-1 showed rapid activation if leaf segments were detached from the plant. However, the expression of CEVI-1 , either during disease or on detachment, was controlled by way of an SA-independent pathway, and neither ethylene nor jasmonic acid and wounding were able to induce expression of CEVI-1 in the plant (Mayda et al, 2000). These findings suggested that the expression of CEVI-1 could be controlled by a novel signaling pathway activated during disease in susceptible tomato plants.…”

“…These findings suggested that the expression of CEVI-1 could be controlled by a novel signaling pathway activated during disease in susceptible tomato plants. Additionally, the observation that the constitutive expression of CEVI-1 :: GUS in the Arabidopsis dth mutants concurs with an auxin-resistant phenotype in the plant prompted us to suggest that the mechanism upregulating the expression of CEVI-1 is related to an induced insensitivity to auxin that might be primed during disease (Mayda et al, 2000).…”

“…We recently described the isolation of dth ( detachment ) mutants from Arabidopsis, which are defined as mutants displaying constitutive expression of the reporter ␤ -glucuronidase ( GUS ) gene driven by the promoter of the tomato CEVI-1 gene (Mayda et al, 2000). In tomato plants, CEVI-1 expression was shown to be transcriptionally activated, along with other defense-related genes, during the course of compatible plant-virus interactions (e.g., tomato mosaic virus).…”

Identificación y caracterización de la familia de factores DBP, nuevos reguladores de la expresión génica en plantas.

“…syringae). En cuanto a su patrón de expresión, CEVI1 no es capaz de responder a tratamientos con las moléculas señalizadoras clásicas de defensa como el SA, ET o JA, ni a estímulos de herida (Mayda et al, 2000a). Todos estos datos sugieren que la expresión del gen CEVI1 parece responder a una nueva vía de señalización de defensa en plantas.…”