Characterization of two Pleiotropic Drug Resistance transporters from Nicotiana plumbaginifolia
(2007)
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- Authors
- Supervisors
- Boutry, Marc
- Abstract
- ABC (ATP Binding Cassette) transporters are involved in the active transport of a large variety of metabolites. In Arabidopsis and rice, they constitute a large gene family organized in subfamilies. Our laboratory has developed a functional study of ABC transporters of the PDR subfamily in Nicotiana tabacum and N. plumbaginifolia. NpPDR1 was shown to transport the antifungal diterpene sclareol. Expression analysis localized the NpPDR1 protein to the trichomes and roots. Furthermore, NpPDR1 expression was strongly induced in the whole leaf after insect or microbial aggression, suggesting that this ABC transporter might be involved in plant defense. Finally, silencing of NpPDR1 expression by RNA interference resulted in increased susceptibility of the plants to infection by Botrytis cinerea . The first aim of this study was to reproduce this last observation in controlled conditions and to determine whether NpPDR1-silenced N. plumbaginifolia plants were more susceptible to infection by other agronomically important fungal pathogens such as Fusarium oxysporum or Rhizoctonia solani. Preliminary pathogenicity tests indicated that the NpPDR1-silenced plants were more susceptible than the wild-type to infection by these three pathogens under the tested conditions and thus support the hypothesis that NpPDR1 is involved in the plant defense. The second and main objective of this work was to study another ABC transporter gene, NpPDR2 belonging to the as yet uncharacterized PDR cluster IV. We have detected its expression at the RNA level in flowers and roots of N. plumbaginifolia plants. We cloned the putative NpPDR2 transcription promoter and fused it to the -glucuronidase (GUS) reporter gene. Analysis of transgenic tobacco expressing this chimeric gene confirmed the expression pattern obtained at the RNA level. More specifically, we found that NpPDR2 is expressed around the conductive tissues of the mature flower style in a pollination dependent manner. In the root, NpPDR2 expression was localized to cells surrounding conductive tissues as well. In conclusion, NpPDR2 is the first gene of PDR cluster IV to be characterized. Its expression pattern suggests that this gene is not related to biotic stress
- Affiliations
Citations
Trombik, T. (2007). Characterization of two Pleiotropic Drug Resistance transporters from Nicotiana plumbaginifolia. https://hdl.handle.net/2078.5/124114