| Autor: |
Narváez-Barragán DA; Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico., Tovar-Herrera OE; Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico.; Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel., Torres M; Centro de Ciencias Genómicas. Universidad Nacional Autónoma de México, 62110, Cuernavaca, Morelos, Mexico., Rodríguez M; Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico., Humphris S; The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK., Toth IK; The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK., Segovia L; Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico., Serrano M; Centro de Ciencias Genómicas. Universidad Nacional Autónoma de México, 62110, Cuernavaca, Morelos, Mexico., Martínez-Anaya C; Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico. cma@ibt.unam.mx. |
| Abstrakt: |
Expansins are encoded by some phytopathogenic bacteria and evidence indicates that they act as virulence factors for host infection. Here we analysed the expression of exl1 by Pectobacterium brasiliense and Pectobacterium atrosepticum. In both, exl1 gene appears to be under quorum sensing control, and protein Exl1 can be observed in culture medium and during plant infection. Expression of exl1 correlates with pathogen virulence, where symptoms are reduced in a Δexl1 mutant strain of P. atrosepticum. As well as Δexl1 exhibiting less maceration of potato plants, fewer bacteria are observed at distance from the inoculation site. However, bacteria infiltrated into the plant tissue are as virulent as the wild type, suggesting that this is due to alterations in the initial invasion of the tissue. Additionally, swarming from colonies grown on MacConkey soft agar was delayed in the mutant in comparison to the wild type. We found that Exl1 acts on the plant tissue, probably by remodelling of a cell wall component or altering the barrier properties of the cell wall inducing a plant defence response, which results in the production of ROS and the induction of marker genes of the JA, ET and SA signalling pathways in Arabidopsis thaliana. Exl1 inactive mutants fail to trigger such responses. This defence response is protective against Pectobacterium brasiliense and Botrytis cinerea in more than one plant species. |
