Editorial: Advances in breeding for wheat disease resistance

Wheat is the most widely planted crop on the planet and contributes up to 20% of total calorie intake for humankind. Maintaining wheat yields is crucial to feeding the world’s people, especially as climate models suggest that rising global temperatures will negatively affect wheat production (Asseng et al., 2015). Diseases of wheat take an important toll, annually robbing humanity of 20% or more of the crop on a global basis (Savary et al., 2019; Savary and Willocquet, 2021). Changes in weather patterns may accelerate pathogen life cycles and escalate shifts in pathogen populations and virulence, posing significant challenges to disease resistance breeding. As well, global trade may increase the chances for a pathogen to spread rapidly and adapt to novel environments and even hosts, leading to emerging diseases. The release and use of wheat cultivars with effective and durable disease resistance is more important now than ever. This is so for multiple reasons. First, disease resistance stabilizes yields and reduces economic losses, saving money for producers who are already facing major challenges due to rising temperatures, more frequent and unpredictable natural disasters, and high and rising costs of inputs such as pesticides (FAO, 2021; Lüttringhaus et al., 2021; Miedaner and Juroszek, 2021). Second, greater reliance on disease resistance can slow pathogen spread and multiplication, prolonging the useful life of available pesticide chemistries so they will be effective when needed to manage severe epidemics (Brent et al., 2007). Third, the growing use of conservation tillage, which is vital for soil health and stabilization, has elevated the importance of diseases such as Fusarium head blight that cannot be completely managed with fungicides (Aboukhaddour et al., 2020). Breeding for disease resistance in wheat has made major technological advances, but still faces important challenges. Prominent among those challenges is the need to develop cultivars for a tremendous diversity of agro-ecological environments, production practices, and discrete market classes (Cowger, 2021). Another challenge is that major genes such as those traditionally deployed to manage wheat rust diseases are often rapidly overcome. This requires a focus on quantitative and race non-specific resistance that may be harder to introgress, select for, and retain in a multi-trait context (Cowger and Brown, 2019; van Esse et al., 2020). The more genes are identified and their mechanisms of action elucidated, the more tools will be available to researchers and breeders to assemble genetically novel germplasm with improved and more durable resistance. The authors who have contributed to this Research Topic tackle those challenges by providing new resources and tools to aid wheat breeders across the globe. The 18 original articles cover a good sample of the world’s most important wheat diseases and the state-of-the-art techniques applied by researchers to identify and evaluate the relevant disease resistance traits. For example, wheat blast is an emergent and damaging disease that has jumped continents from Latin America to Asia, as explained in a comprehensive review by Singh et al., 2021. A team of blast researchers has compared marker-assisted and genomic selection using precision phenotyping of blast resistance conferred by the 2NS translocation (Juliana et al., 2022), which is partial and sometimes background-dependent. Another major threat to global wheat production is Fusarium head blight. Three articles in this Research Topic offer important new resources for breeding cultivars with effective FHB resistance. The Brazilian spring cultivar Surpresa provides a new source of resistance not currently used (Poudel et al. 2022). Three resistance loci (Fhb1, Fhb4, and Fhb5) were introgressed as a pyramid into desirable Chinese white and red semi-winter wheat lines (Zhang et al., 2021). And a novel technique could speed up the development of FHB-resistant winter wheat germplasm, increasing breeding generations from two to three per year (Zakieh et al. 2021). Researchers used various approaches to identify new sources of resistance to the three wheat rusts (stem, stripe, and leaf). A new stem rust resistance gene was mapped in the durum wheat variety Kronos and introgressed into common wheat using co-segregating DNA markers (Li et al., 2021). The effects of combinations of leaf rust resistance genes were investigated in a Canadian wheat double-haploid population (McCallum and Hiebert, 2022) and in a durably resistant Canadian wheat cultivar (Bokore et al., 2022). A multi-parent advanced generation intercross (MAGIC) wheat population was used to map adult-plant and seedling resistance to stripe rust in Germany (Rollar et al., 2021). A genome-wide association study was used to identify stripe rust resistance loci in a panel of Chinese wheat landraces (Yao et al., 2021). And QTL mapping led to identification of stripe and leaf rust loci in an Afghan landrace (Zhang et al., 2022), a Chinese landrace (Wang et al., 2022), and the CIMMYT wheat line “Mucuy” (Lan et al., 2022; so far this is an abstract, need the URL to the full article when it’s available). Breeding wheat cultivars with resistance to powdery mildew requires a constant stream of new resistance sources, thanks to the pathogen’s ability to rapidly overcome host resistance through adaptation. The efficacy of a set of new resistance genes introgressed from Middle Eastern wild wheat relatives was measured using powdery mildew populations from various wheat growing regions affected by the disease (Kloppe et al., 2022). A more unusual wild relative of wheat, Psathyrostachys huashanica, which is found only in the Huashan Mountains of China, also furnished novel resistance to wheat powdery mildew (Liu et al., 2021). A previously unidentified source of resistance to Hessian fly was identified in spring wheat cultivars of the U.S. Pacific Northwest (Prather et al., 2022). And in a twist, a locus conferring not resistance but susceptibility, in this case to tan spot, was identified in U.S. bi-parental spring wheat mapping populations and narrowed to a region encompassing seven candidate genes (Running et al., 2022). Last but not least, an interesting look under the ground revealed that rhizosphere microbiomes differed among wheat genotypes and had an impact on pathogenicity of Rhizoctonia solani, suggesting the potential to manage Rhizoctonia root rot with wheat genotypes that recruit microbiomes associated with improved plant fitness and suppression of the fungal pathogen (Dilla-Ermita et al., 2021). For this Research Topic, we have collected articles that demonstrate how cutting-edge approaches to breeding are being brought to bear on some of the chief diseases threatening the world’s wheat production systems. The authors’ contributions are of the highest quality, and illustrate the strong international interest in this topic. These reports help breeders everywhere assess and employ novel and potentially durable resistance to wheat diseases. They will make a practical difference in helping safeguard global wheat yields in the challenging years to come

General disease resistance loci against biotrophic pathogens in wheat

Dissertação de Mestrado Integrado em Arquitectura, apresentada ao Departamento de Arquitectura da Faculdade de Ciências e Tecnologia da Universidade de Coimbra, sob a orientação do Prof. Doutor Walter Rossa.Um ano depois de a UNESCO inscrever a “Universidade de Coimbra - Alta e Sofia” na lista do Património Mundial da Humanidade e face ao desafio académico de Coimbra Capital Europeia da Cultura em 2027, este trabalho tem como objectivo analisar e perceber como se alterou a imagem urbana da cidade e de que maneira o branding que proponho para a mesma vai clarificar essa imagem, de forma a criar uma linguagem coerente e clara, que traga valor para Coimbra. O trabalho divide-se em quatro partes. A primeira exibe a importância do branding para as cidades, entendendo que este conceito é fundamental para que Coimbra construa uma visão de futuro, com uma melhoria no espaço público e com uma linguagem coerente entre a Universidade a tudo o que a dinamiza. A segunda parte, analisa a evolução da imagem e do sistema urbano do espaço que escolhi como exemplo de trabalho, a antiga Quinta de Santa Cruz, onde foi criado o “boulevard” da cidade, a Avenida Sá da Bandeira e a Praça da República. Na terceira parte, vou analisar criticamente estes dois espaços de maneira a perceber como alterar a imagem suja que a cidade tem hoje, clarificando-a e sabendo que esta zona tem tudo para ser o verdadeiro centro cosmopolita de Coimbra. Por último, associo a esse exemplo um de outra natureza, mas com ele coerente no compto geral do processo, a criação de um logótipo que vai qualificar a cidade e que vai estar presente na mudança do sistema urbano, ajudando a clarificar a imagem da cidade.One year later that UNESCO aggregated “Universidade de Coimbra - Alta e Sofia” at the list of World Heritage Site and the academic challenge of Coimbra European Capital of Culture in 2027, this work aims to analyze and understand how changed the image of urban city , and that way, how the branding that i’ll propose for the city, will clarify this image in order to create a coherent and clear language that bring value to Coimbra. The work is divided into four parts. A first that displays the importance of branding for cities, and how these concept is fundamental to Coimbra build a vision of future, with an improvement in public space and with identical language between the University and everything that surrounds it. The second part examines the evolution of the urban system and the image of the space that i found as an example to work, the old Quinta de Santa Cruz, where the “boulevard” of the city with the Avenue Sá da Bandeira and Republic Square was created. In the third part i will analyze and criticize these two spaces so that you can understand how to clean the soiled image that the city transpires today, in order to make clear that this space has everything to be the true cosmopolitan center of Coimbra. Finally i will associate this example to other of a diferent nature, but coherent in the overall process, the creation of a logo that will qualify the city and that will be present in the changing of urban system helping to clarify the city’s image

Genome-wide association mapping of resistance to septoria nodorum leaf blotch in a nordic spring wheat collection

Parastagonospora nodorum is the causal agent of Septoria nodorum leaf blotch (SNB) in wheat (Triticum aestivum L.). It is the most important leaf blotch pathogen in Norwegian spring wheat. Several quantitative trait loci (QTL) for SNB susceptibility have been identified. Some of these QTL are the result of underlying gene-for-gene interactions involving necrotrophic effectors (NEs) and corresponding sensitivity (Snn) genes. A collection of diverse spring wheat lines was evaluated for SNB resistance and susceptibility over seven growing seasons in the field. In addition, wheat seedlings were inoculated and infiltrated with culture filtrates (CFs) from four single spore isolates and infiltrated with semipurified NEs (SnToxA, SnTox1, and SnTox3) under greenhouse conditions. In adult plants, the most stable SNB resistance QTL were located on chromosomes 2B, 2D, 4A, 4B, 5A, 6B, 7A, and 7B. The QTL on chromosome 2D was effective most years in the field. At the seedling stage, the most significant QTL after inoculation were located on chromosomes 1A, 1B, 3A, 4B, 5B, 6B, 7A, and 7B. The QTL on chromosomes 3A and 6B were significant both after inoculation and CF infiltration, indicating the presence of novel NE–Snn interactions. The QTL on chromosomes 4B and 7A were significant in both seedlings and adult plants. Correlations between SnToxA sensitivity and disease severity in the field were significant. To our knowledge, this is the first genome-wide association mapping study (GWAS) to investigate SNB resistance at the adult plant stage under field conditions

Characterization of polyploid wheat genomic diversity using a high-density 90,000 single nucleotide polymorphism array

High-density single nucleotide polymorphism (SNP) genotyping arrays are a powerful tool for studying genomic patterns of diversity, inferring ancestral relationships between individuals in populations and studying marker-trait associations in mapping experiments. We developed a genotyping array including about 90,000 gene-associated SNPs and used it to characterize genetic variation in allohexaploid and allotetraploid wheat populations. The array includes a significant fraction of common genome-wide distributed SNPs that are represented in populations of diverse geographical origin. We used density-based spatial clustering algorithms to enable high-throughput genotype calling in complex data sets obtained for polyploid wheat. We show that these model-free clustering algorithms provide accurate genotype calling in the presence of multiple clusters including clusters with low signal intensity resulting from significant sequence divergence at the target SNP site or gene deletions. Assays that detect low-intensity clusters can provide insight into the distribution of presence-absence variation (PAV) in wheat populations. A total of 46 977 SNPs from the wheat 90K array were genetically mapped using a combination of eight mapping populations. The developed array and cluster identification algorithms provide an opportunity to infer detailed haplotype structure in polyploid wheat and will serve as an invaluable resource for diversity studies and investigating the genetic basis of trait variation in wheat.Shichen Wang, Debbie Wong, Kerrie Forrest, Alexandra Allen, Shiaoman Chao, Bevan E. Huang, Marco Maccaferri, Silvio Salvi, Sara G. Milner, Luigi Cattivelli, Anna M. Mastrangelo, Alex Whan, Stuart Stephen, Gary Barker, Ralf Wieseke, Joerg Plieske, International Wheat Genome Sequencing Consortium, Morten Lillemo, Diane Mather, Rudi Appels, Rudy Dolferus, Gina Brown-Guedira, Abraham Korol, Alina R. Akhunova, Catherine Feuillet, Jerome Salse, Michele Morgante, Curtis Pozniak, Ming-Cheng Luo, Jan Dvorak, Matthew Morell, Jorge Dubcovsky, Martin Ganal, Roberto Tuberosa, Cindy Lawley, Ivan Mikoulitch, Colin Cavanagh, Keith J. Edwards, Matthew Hayden, and Eduard Akhuno

Dynamic modelling of ammonia biofiltration from waste gases

A dynamic model to describe ammonia removal in a gas-phase biofilter was developed. The math-ematical model is based on discretized mass balances and detailed nitrification kinetics that includeinhibitory effects caused by free ammonia (FA) and free nitrous acid (FNA). The model was able to pre-dict experimental results operation under different loading rates (from 3.2 to 13.2 g NH3h-1m-3). In par-ticular the model was capable of reproducing inhibition caused by high inlet ammonia concentrations. Alsoelimination capacity was accurately predicted. Experimental data was also used to optimize certain modelparameters such as the concentration of ammonia- and nitrite-oxidizing biomass.Peer ReviewedPostprint (published version