title: ZD958 is a low-nitrogen-efficient maize hybrid at the seedling stage among five maize and two teosinte lines.
abstract: ZD958 was the most low-N-efficient line among five maize and two teosinte lines. Zea parviglumis and Zea diploperennis were insensitive to N limitation. Maize and teosinte genetically and evolutionarily diverged in gene regulation. GDH2, ASN2, and T4 were consistently down-regulated across seven lines. Maternal asymmetric inheritance and heterosis vigor made ZD958 low-N-efficient. Nitrogen (N) deficiency remains a serious limiting factor for maize production in many developing countries. It is particularly important to better understand how hybrid maize responds to N limitation. ZD958, a dominant high-yield hybrid in North China, was comparatively analyzed with four other maize and two teosinte lines at physiological and transcriptional levels. ZD958 was the most low-N-efficient line among five maize and two teosinte lines due to its largest biomass accumulation at a lowest N concentration under N limitation; while Zea parviglumis and Zea diploperennis had large root systems and were insensitive to N limitation. In anti-parallel with down-regulation of N metabolic genes in the ZD958 root, carbon allocation towards the root was enhanced for the significant increase in the root length. Variations in expression patterns of ten genes mediating N uptake, transport, and metabolism indicated large genetic and evolutionary divergence among seven lines under N limitation. Notably, GDH2, ASN2, and VAAT5 were consistently down-regulated under N limitation across these maize and teosinte lines, suggesting essential evolutionary conservation of gene regulation in response to N limitation and providing molecular markers for N nutritional diagnosis. Asymmetric inheritance, mostly from its maternal donor Z58, and heterosis vigor made ZD958 low-N-efficient at the seedling stage. The superior traits in crown roots in ZD958 may be derived from its paternal donor Chang7-2. Thus, Z58, Chang7-2, and two wild maize lines (Z. parviglumis and Z. diploperennis) provide valuable germplasms for N-efficient and large-root maize breeding.
authors.affiliation: Department of Plant Nutrition, China Agricultural University, Beijing, 100193, China.
authors.forename: Jienan
authors.initials: J
authors.lastname: Han
authors.forename: Lifeng
authors.initials: L
authors.lastname: Wang
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zheng
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Pan
authors.forename: Huiyong
authors.initials: H
authors.lastname: Li
authors.forename: Fanjun
authors.initials: F
authors.lastname: Chen
authors.forename: Xuexian
authors.initials: X
authors.lastname: Li
mesh_terms: D017343:Genes, Plant; D009584:Nitrogen / Q000378:metabolism*; D014158:Transcription, Genetic; D003313:Zea mays / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D009584:Nitrogen