Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana.
In flowers with dry stigmas, pollen development, pollination, and pollen tube growth require spatial and temporal regulation of water and nutrient transport. To better understand the molecular mechanisms involved in reproductive processes, we characterized NIP4;1 and NIP4;2, two pollen-specific aquaporins of Arabidopsis thaliana. NIP4;1 and NIP4;2 are paralogs found exclusively in the angiosperm lineage. Although they have 84% amino acid identity, they displayed different expression patterns. NIP4;1 has low expression levels in mature pollen, while NIP4;2 expression peaks during pollen tube growth. Additionally, NIP4;1pro:GUS flowers showed GUS activity in mature pollen and pollen tubes, whereas NIP4;2pro:GUS flowers only in pollen tubes. Single T-DNA mutants and double artificial microRNA knockdowns had fewer seeds per silique and reduced pollen germination and pollen tube length. Transport assays in oocytes showed NIP4;1 and NIP4;2 function as water and nonionic channels. We also found that NIP4;1 and NIP4;2 C termini are phosphorylated by a pollen-specific CPK that modifies their water permeability. Survival assays in yeast indicated that NIP4;1 also transports ammonia, urea, boric acid, and H2O2 Thus, we propose that aquaporins NIP4;1 and NIP4;2 are exclusive components of the reproductive apparatus of angiosperms with partially redundant roles in pollen development and pollination.
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina.
Juliana Andrea Pérez
0000-0002-8959-5500
JA
Di Giorgio
Metalloid Transport Group, Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany.
Gerd Patrick
GP
Bienert
Instituto de Genética Ewald A. Favret (CICVyA-INTA), Castelar, CC25 (1712) Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033AAJ Buenos Aires, Argentina.
Nicolás Daniel
0000-0001-5012-240X
ND
Ayub
Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-CONICET-UBA), Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina.
Agustín
0000-0003-0503-5897
A
Yaneff
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina.
María Laura
ML
Barberini
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina.
Martín Alejandro
0000-0002-3444-3294
MA
Mecchia
Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-CONICET-UBA), Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina.
Gabriela
0000-0003-3350-4750
G
Amodeo
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina Instituto de Genética Ewald A. Favret (CICVyA-INTA), Castelar, CC25 (1712) Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033AAJ Buenos Aires, Argentina.
Gabriela Cynthia
0000-0002-3492-1268
GC
Soto
Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina prometeo@dna.uba.ar.
Jorge Prometeo
0000-0002-5719-4833
JP
Muschietti
D000641:Ammonia / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D001888:Boric Acids / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D006861:Hydrogen Peroxide / Q000378:metabolism; D011058:Pollen / Q000235:genetics / Q000378:metabolism*; D054817:Pollination / Q000235:genetics / Q000502:physiology; D014508:Urea / Q000378:metabolism
D029681:Arabidopsis Proteins; D001888:Boric Acids; D000641:Ammonia; D014508:Urea; D006861:Hydrogen Peroxide; C032688:boric acid