Expression and roles of NpABC1 : a Nicotiana plumbaginifolia ABC transporter involved in the plant-pathogen response
(2003)
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- Authors
- Supervisors
- Boutry, Marc
- Abstract
- ATP-binding cassette (ABC) transporters represent one of the largest gene families in prokaryotes and eukaryotes, and transport a variety of substrates in organelles or to the intra- or extracellular space. They fulfill different physiological roles, such as import of small nutrients, drug resistance, transport of cytosolic peptides for antigen presentation, or ion channel regulation. In plants, the ABC protein family is particularly large, with 131 members in Arabidopsis, only a minority of which has been characterized at the functional level. Numerous ABC proteins belonging to the multidrug resistance-associated protein (MRP) cluster were characterized and shown to be involved in sequestering secondary metabolites in the vacuole. Much less is known concerning the members of the pleiotropic drug resistance (PDR) cluster. Among them, the Nicotiana plumbaginifolia ABC1 (NpABC1) has been localized to the plasma membrane and is thought to transport diterpenes, such as sclareol, involved in the plant defense. We show here that the NpABC1 gene is expressed in the leaf hairs involved in the secretion of defense molecules, but that it is also expressed in the whole leaf following insect or bacteria attack. Blocking NpABC1 expression through RNA interference rendered transgenic plants more susceptible to bacterial infection and sclareol toxicity. These data indicate that NpABC1 is involved in the pathogen response, possibly via sclareol and other antimicrobial related terpene secretion, and define a new role for the ABC transporter family. Furthermore, NpABC1 has been localized in the petal epidermis cells involved in volatile production. The highest expression was found when the flower is ready to function as a pollen donor and receiver, a developmental period corresponding to the highest emission of pollinator attracting molecules. This suggests the involvement of the ABC protein in the pollinator attraction via volatile emission. The detection of NpABC1 expression in the N. plumbaginifolia root remains to be investigated since preventing its expression through RNA interference resulted in rotting of the root tissues. These data show that NpABC1 is expressed in different organs and is involved in various physiological roles linked to the transport of secondary metabolites.
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Citations
Stukkens, Y. (2003). Expression and roles of NpABC1 : a Nicotiana plumbaginifolia ABC transporter involved in the plant-pathogen response. https://hdl.handle.net/2078.5/98321