Biology subjects

Kasemsap, P.

Publications and source records attributed to Kasemsap, P..

3 recordsLinked to original sources

bioRxiv2026

Natural Variations of Spring Wheat Nitrogen and Carbon Assimilation under Different Inorganic Nitrogen Forms and CO2 levels

Wheat (Triticum aestivum L.) production depends upon nitrogen fertilization and may be threatened by the climate conditions anticipated in the next few decades. The natural variation in the ability of wheat to assimilate carbon and different inorganic nitrogen forms, nitrate (NO3-) and ammonium (NH4+), into vegetative growth remains unexplored. Here, we evaluated growth under either NO3- or NH4+ as a sole nitrogen source for 875 spring hexaploid wheat accessions that represent the genetic diversity within the global germplasm. These accessions varied over 8-fold in vegetative biomass but grew similarly under moderate levels of either nitrogen form. At high, potentially toxic concentrations of NH4+, however, they lost approximately 20% of their biomass. We characterized the influence of changing CO2 levels in bi-parental Nested Association Mapping populations. Genetic backgrounds determined wheat biomass responses to CO2 enrichment and nitrogen form. Genome-Wide Association and linkage mapping identified certain loci as consistently associated with biomass accumulation under different nitrogen forms and CO2 levels. These results will assist breeding efforts to develop food crops that are resilient to the worlds climate changes.

plant biology↗

bioRxiv2024

Genome-wide Association Study of Rice Vegetative Biomass under Different Inorganic Nitrogen Forms: Ammonium or Nitrate

Rice is the most important source of daily calories in human diets and second only to wheat as the most important protein source. Rice is generally exposed to high ammonium (NH4+) levels in the rhizosphere but may employ both NH4+ and nitrification-derived nitrate (NO3-) as major sources of nitrogen. However, the genetic basis underlying rice adaptation to different nitrogen forms remains poorly characterized. Here, we assessed biomass under either NH4+ or NO3- as a sole nitrogen source in 390 accessions from the USDA Rice Diversity Panel 1. Rice effectively used either form of nitrogen to support early growth. Tolerance to a high-NH4+ exposure was correlated with biomass under NO3- and lower NH4+ levels. Both genotype and nitrogen source strongly influenced biomass accumulation and partitioning between shoot and root. Root showed the greatest biomass variability and sensitivity to nitrogen source. Genome-wide analyses identified 176 single nucleotide polymorphism (SNP) markers associated with biomass across the full diversity panel and individual populations. The majority of the associations were unique to the individual nitrogen source. We compiled a list of candidate genes, including putative genes involved in nitrogen metabolism, located within 150 kb of 112 most significant SNPs, each with at least 3 adjacent markers detected under the same combination of population and nitrogen source. A flexible consumer, rice may employ distinct genetic mechanisms to use different nitrogen sources, making the species more resilient to fluctuations in soil nitrogen. These insights can guide matching rice genotypes with fertilizer management to improve nitrogen-use efficiency.

plant biology↗

bioRxiv2023

Genetic adaptation to ammonium sustains wheat grain quality and alleviates acclimation to CO2 enrichment

Plants synthesize protein through assimilating inorganic nitrogen. Yet, the extent to which soil nitrogen sources alter crop responses to atmospheric CO2 remains uncertain. We assessed wheat (Triticum aestivum L.) biomass under CO2 enrichment in genotypes that demonstrated a preference for ammonium (NH4+) or nitrate (NO3-), and contrasting degrees of NH4+ tolerance. Nitrogen-form preference, but not NH4+ tolerance, correlated with CO responses. Notably, NH4+-preferring genotypes maintained higher biomass and sustained grain nitrogen concentrations, thus avoiding CO2 acclimation, the decline in biomass stimulation after prolonged exposure to CO2 enrichment. Furthermore, NH4+ nutrition accelerated flowering and increased spike biomass. Breeding for NH4+-adapted genotypes may not only improve climate resilience, but also potentially accelerate development and increase yield without any penalty on grain quality. Because wheat provides 20% of the protein and carbohydrate in the human diet, our study provided strategies to sustain food security under the atmospheric conditions anticipated in the future. HighlightBreeding for NH4+-adapted genotypes may not only improve climate resilience, but also potentially accelerate development and increase yield without any penalty on grain quality under elevated CO2 atmospheres.

plant biology↗