title: Enhanced proton translocating pyrophosphatase activity improves nitrogen use efficiency in Romaine lettuce.
abstract: Plant nitrate (NO3(-)) acquisition depends on the combined activities of root high- and low-affinity NO3(-) transporters and the proton gradient generated by the plasma membrane H(+)-ATPase. These processes are coordinated with photosynthesis and the carbon status of the plant. Here, we present the characterization of romaine lettuce (Lactuca sativa 'Conquistador') plants engineered to overexpress an intragenic gain-of-function allele of the type I proton translocating pyrophosphatase (H(+)-PPase) of Arabidopsis (Arabidopsis thaliana). The proton-pumping and inorganic pyrophosphate hydrolytic activities of these plants are augmented compared with control plants. Immunohistochemical data show a conspicuous increase in H(+)-PPase protein abundance at the vasculature of the transgenic plants. Transgenic plants displayed an enhanced rhizosphere acidification capacity consistent with the augmented plasma membrane H(+)-ATPase proton transport values, and ATP hydrolytic capacities evaluated in vitro. These transgenic lines outperform control plants when challenged with NO3(-) limitations in laboratory, greenhouse, and field scenarios. Furthermore, we report the characterization of a lettuce LsNRT2.1 gene that is constitutive up-regulated in the transgenic plants. Of note, the expression of the LsNRT2.1 gene in control plants is regulated by NO3(-) and sugars. Enhanced accumulation of (15)N-labeled fertilizer by transgenic lettuce compared with control plants was observed in greenhouse experiments. A negative correlation between the level of root soluble sugars and biomass is consistent with the strong root growth that characterizes these transgenic plants.
authors: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
authors: Julio
authors: J
authors: Paez-Valencia
authors: Jonathan
authors: J
authors: Sanchez-Lares
authors: Ellen
authors: E
authors: Marsh
authors: Liane T
authors: LT
authors: Dorneles
authors: Mirella P
authors: MP
authors: Santos
authors: Diego
authors: D
authors: Sanchez
authors: Alexander
authors: A
authors: Winter
authors: Sean
authors: S
authors: Murphy
authors: Jennifer
authors: J
authors: Cox
authors: Marcin
authors: M
authors: Trzaska
authors: Jason
authors: J
authors: Metler
authors: Alex
authors: A
authors: Kozic
authors: Arnoldo R
authors: AR
authors: Facanha
authors: Daniel
authors: D
authors: Schachtman
authors: Charles A
authors: CA
authors: Sanchez
authors: Roberto A
authors: RA
authors: Gaxiola
mesh_terms: D000143:Acids / Q000378:metabolism; D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000201:enzymology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D002241:Carbohydrates / Q000032:analysis; D002244:Carbon / Q000378:metabolism; D005308:Fertilizers; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005818:Genetic Engineering; D007150:Immunohistochemistry; D043564:Inorganic Pyrophosphatase / Q000235:genetics / Q000378:metabolism*; D018545:Lactuca / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D000091285:Nitrate Transporters; D009566:Nitrates / Q000494:pharmacology; D009584:Nitrogen / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified; D012995:Solubility
chemical_list: D000143:Acids; D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D002241:Carbohydrates; D005308:Fertilizers; D000091285:Nitrate Transporters; D009566:Nitrates; D002244:Carbon; C505048:AVP1 protein, Arabidopsis; D043564:Inorganic Pyrophosphatase; D009584:Nitrogen