Abstract
Thaxtomin A (TXT) is a phytotoxin produced by all plant-pathogenic
Streptomyces scabies
involved in the potato scab disease. Their pathogenicity was previously correlated with the production of TXT. Calcium is known to be an essential second messenger associated with pathogen-induced plant responses and cell death. We have effectively shown that in
Arabidopsis thaliana
cell suspensions, TXT induces an early short lived Ca
2+
influx which is involved in the cell death process and other TXT-induced responses. We extended our study to
Nicotiana tabacum
BY2 by monitoring cell death and changes in cytosolic calcium concentration on cells expressing the apoaequorine Ca
2+
reporter protein to compare the responses to TXT of the two model plants, tobacco and
A. thaliana
. Our investigations show that cell death in BY2 appeared to be dose dependent with a lag of sensitivity comparing to
A. thaliana
. Moreover, pathway leading to cell death in BY2 does not involve calcium signaling. Our results suggest that different pathways are engaged in
A. thaliana
and
N. tabacum
BY2 to achieve the same response to TXT.