JXB Advance Access originally published online on April 10, 2007
Journal of Experimental Botany 2007 58(7):1617-1626; doi:10.1093/jxb/erl298
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RESEARCH PAPER |
Phytotoxic effects of trichothecenes on the growth and morphology of Arabidopsis thaliana
1Division of Life Science, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan
2Division of Functional Genomics, Advanced Science Research Center, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-0934, Japan
3Plant and Microbial Metabolic Engineering Research Unit and Laboratory for Remediation Research, Discovery Research Institute (DRI), Plant Science Center (PSC1), RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
To whom correspondence should be addressed. E-mail: tnish9{at}kenroku.kanazawa-u.ac.jp
Non-volatile sesquiterpenoids, a trichothecene family of phytotoxins such as deoxynivalenol (DON) and T-2 toxin, contain numerous molecular species and are synthesized by phytopathogenic Fusarium species. Although trichothecene chemotypes might play a role in the virulence of individual Fusarium strains, the phytotoxic action of individual trichothecenes has not been systematically studied. To perform a comparative analysis of the phytotoxic action of representative trichothecenes, the growth and morphology of Arabidopsis thaliana growing on media containing these compounds was investigated. Both DON and diacetoxyscirpenol (DAS) preferentially inhibited root elongation. DON-treated roots were less organized compared with control roots. Moreover, preferential inhibition of root growth by DON was also observed in wheat plants. In addition, T-2 toxin-treated seedlings exhibited dwarfism with aberrant morphological changes (e.g. petiole shortening, curled dark-green leaves, and reduced cell size). These results imply that the phytotoxic action of trichothecenes differed among their molecular species. Cycloheximide (CHX)-treated seedlings displayed neither feature, although it is known that trichothecenes inhibit translation in eukaryotic ribosomes. Microarray analyses suggested that T-2 toxin caused a defence response, the inactivation of brassinosteroid (BR), and the generation of reactive oxygen species in Arabidopsis. This observation is in agreement with our previous reports in which trichothecenes such as T-2 toxin have an elicitor-like activity when infiltrated into the leaves of Arabidopsis. Since it has been reported that BR plays an important role in a broad range of disease resistance in tobacco and rice, inactivation of BR might affect pathogenicity during the infection of host plants by trichothecene-producing fungi.
Key words: Brassinosteroid, defence response, dwarf, morphology, phytotoxin, trichothecene
* Present address: Presidential Office, Agricultural Chemicals Inspection Station (ACIS), 2–772 Suzuki-cho, Kodaira, Tokyo 187-0011, Japan.
Received 5 October 2006; Revised 8 December 2006 Accepted 11 December 2006