title: Vacuolar H(+)-Pyrophosphatase AVP1 is Involved in Amine Fungicide Tolerance in Arabidopsis thaliana and Provides Tridemorph Resistance in Yeast.
abstract: Amine fungicides are widely used as crop protectants. Their success is believed to be related to their ability to inhibit postlanosterol sterol biosynthesis in fungi, in particular sterol-Δ(8),Δ(7)-isomerases and sterol-Δ(14)-reductases, with a concomitant accumulation of toxic abnormal sterols. However, their actual cellular effects and mechanisms of death induction are still poorly understood. Paradoxically, plants exhibit a natural resistance to amine fungicides although they have similar enzymes in postcicloartenol sterol biosynthesis that are also susceptible to fungicide inhibition. A major difference in vacuolar ion homeostasis between plants and fungi is the presence of a dual set of primary proton pumps in the former (V-ATPase and H(+)-pyrophosphatase), but only the V-ATPase in the latter. Abnormal sterols affect the proton-pumping capacity of V-ATPases in fungi and this has been proposed as a major determinant in fungicide action. Using Saccharomyces cerevisiae as a model fungus, we provide evidence that amine fungicide treatment induced cell death by apoptosis. Cell death was concomitant with impaired H(+)-pumping capacity in vacuole vesicles and dependent on vacuolar proteases. Also, the heterologous expression of the Arabidopsis thaliana main H(+)-pyrophosphatase (AVP1) at the fungal vacuolar membrane reduced apoptosis levels in yeast and increased resistance to amine fungicides. Consistently, A. thaliana avp1 mutant seedlings showed increased susceptibility to this amine fungicide, particularly at the level of root development. This is in agreement with AVP1 being nearly the sole H(+)-pyrophosphatase gene expressed at the root elongation zones. All in all, the present data suggest that H(+)-pyrophosphatases are major determinants of plant tolerance to amine fungicides.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de SevillaSevilla, Spain; Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São PauloSão Paulo, Brazil.
authors.forename: Agustín
authors.initials: A
authors.lastname: Hernández
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla Sevilla, Spain.
authors.forename: Rosana
authors.initials: R
authors.lastname: Herrera-Palau
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla Sevilla, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Madroñal
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla Sevilla, Spain.
authors.forename: Tomás
authors.initials: T
authors.lastname: Albi
authors.affiliation: Centro Andaluz de Biología del Desarrollo and Centre of Biomedical Research in Rare Diseases, ISCIII, Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide Sevilla, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: López-Lluch
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla Sevilla, Spain.
authors.forename: José R
authors.initials: JR
authors.lastname: Perez-Castiñeira
authors.affiliation: Centro Andaluz de Biología del Desarrollo and Centre of Biomedical Research in Rare Diseases, ISCIII, Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide Sevilla, Spain.
authors.forename: Plácido
authors.initials: P
authors.lastname: Navas
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla Sevilla, Spain.
authors.forename: Federico
authors.initials: F
authors.lastname: Valverde
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas, Universidad de Sevilla Sevilla, Spain.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Serrano
keywords: H+-pyrophosphatase; V-ATPase; abnormal sterols; cell death; crop protection; fungicide; pyrophosphate; vacuole