Arango, Jacobo

Arévalo, Ashly

Chavez, Lucia

Ishitani, Manabu

Karwat, Hannes

Miles, John W.

Moreta, Danilo

Nuñez, Jonathan

Peters, Michael

Rao, Idupulapati M.

Subbaraoa, Guntur V.

CGSpace

Tropentag, September 17-19, 2014, Prague, Czech Republic“Bridging the gap between increasing knowledge anddecreasing resources”Phenotyping of a Bi-Parental Brachiaria humidicola Population forits Biological Nitrification Inhibition PotentialJacobo Arango1, Jonathan Nuñez1, Danilo Moreta1, Hannes Karwat2, AshleyArevalo1, Manabu Ishitani1, Lucia Chavez1, John Miles1, Guntur Subbarao3, MichaelPeters1, Idupulapati Rao11International Center For Tropical Agriculture (CIAT), Colombia2University of Hohenheim, Inst. of Plant Production and Agroecology in the Tropics and Subtropics,Germany3Japan International Research Center for Agricultural Sciences (JIRCAS), JapanAbstractNitrification is an oxidation process, part of the larger nitrogen (N) cycle in the soil, and ismediated by microorganisms that transform ammonium (NH+4 ) to the water soluble nitrate (NO3-),producing nitrous oxide (N2O, a potent greenhouse gas) as a by-product. Researchers at CIAT-Colombia, in collaboration with JIRCAS-Japan, reported that the tropical forage grass, Brachiariahumidicola (Bh), has the ability to inhibit the nitrification with chemical exudates from their rootsinto the soil. This capacity of Brachiaria grasses is known as biological nitrification inhibition(BNI) and this function could increase N efficiency in crop-livestock systems by improving recoveryof applied N, while reducing NO3- leaching and N2O emissions. Recently, we have been able toimprove methodologies for more reliable quantification of the BNI trait in order to accelerate theprocess of identifying phenotypic differences in BNI ability.Our aim is to quantify phenotypic differences in BNI capacity of a bi-parental hybrid population(n=134) of two Bh accessions with different BNI capacities, CIAT 26146 (medium to low BNI withsexual mode of reproduction)×CIAT 16888 (high BNI with apomictic mode of reproduction), inan attempt to identify QTLs (quantitative trait loci) associated with BNI trait. The phenotypingmethodologies used were: 1) A bioassay using a recombinant Nitrosomonas europaea strain engi-neered to detect changes in nitrification in vivo in the presence of Bh root exudates; 2) A reliableand rapid soil incubation method to determine changes in nitrification in soil where Bh plants weregrown; and 3) A molecular method where both DNA and RNA from soil nitrifying microbes areco-extracted. First, DNA is used to size the nitrifier populations as an indicator for the amount ofnitrification inhibitors released by the Bh roots. Second, cDNA is synthesized using the RNA astemplate, to enable expression analysis of ammonia monooxygenase gene (responsible enzyme forNH+4 oxidation to NO3-) as a functional molecular marker for nitrification process. By using thesedifferent phenotyping methodologies we found high phenotypic variability in BNI capacity amonghybrids. The importance of these results in regulating BNI function in Brachiaria will be discussed.Keywords: Ammonia mono-oxygenase (amoA), brachialactone, Brachiaria humidicola, nitrous oxide,phenotyping, root exudatesContact Address: Jacobo Arango, International Center for Tropical Agriculture (CIAT), Tropical Forages, A A 6713Cali, Colombia, NA Cali, Colombia, e-mail: j.arango@cgiar.org

Phenotyping of a Bi-Parental brachiaria humidicola population for its biological nitrification inhibition potential

https://cgspace.cgiar.org/bitstream/10568/65367/2/Arango_eiy6xeIg.pdf

Phenotyping of a Bi-Parental brachiaria humidicola population for its biological nitrification inhibition potential

Abstract

Similar works

Full text

Available Versions

CGSpace