Nitrogen acquisition in Agave tequilana from degradation of endophytic bacteria.
Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from (15)N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with (15)NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of (15)N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes.
1] Departamento de Química ICET, Universidad Autonoma de Guadalajara, Patria 1201, Lomas del Valle, Zapopan Jalisco, Mexico [2] Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Miguel J
MJ
Beltran-Garcia
Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ USA.
James F
JF
White
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Fernanda M
FM
Prado
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Katia R
KR
Prieto
Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Lydia F
LF
Yamaguchi
Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ USA.
Monica S
MS
Torres
Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Massuo J
MJ
Kato
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Marisa H G
MH
Medeiros
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 05508-000, São Paulo, SP, Brazil.
Paolo
P
Di Mascio
D027882:Agave / Q000378:metabolism* / Q000382:microbiology; D000643:Ammonium Chloride / Q000378:metabolism; D001407:Bacillus / Q000378:metabolism*; D058491:Bacterial Load; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D003853:Deoxyribonucleosides / Q000378:metabolism; D060026:Endophytes / Q000378:metabolism*; D050296:Microbial Viability; D009584:Nitrogen / Q000378:metabolism*; D009586:Nitrogen Fixation / Q000502:physiology; D009587:Nitrogen Isotopes / Q000378:metabolism; D010084:Oxidation-Reduction; D010674:Pheophytins / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism* / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D013559:Symbiosis; D014364:Tryptophan / Q000378:metabolism
D003853:Deoxyribonucleosides; D009587:Nitrogen Isotopes; D010674:Pheophytins; D017382:Reactive Oxygen Species; D000643:Ammonium Chloride; D002734:Chlorophyll; D014364:Tryptophan; D009584:Nitrogen; D000077194:Chlorophyll A