Elimination of the yellow pigment gene PSY-E2 tightly linked to the Fusarium head blight resistance gene Fhb7 from Thinopyrum ponticum

Fhb7 is a major gene that was transferred from Thinopyrum ponticum to chromosome 7D of wheat(Triticum aestivum)and confers resistance to both Fusarium head blight(FHB)and Fusarium crown rot(FCR).However,Fhb7 is tightly linked to the PSY-E2 gene,which causes yellow flour,limiting its application in breeding.To break this linkage,marker K-PSY was developed for tagging PSY-E2 and used with Fhb7 markers to identify recombination between the two genes.Screening 21,000 BC1F2 backcross progeny(Chinese Spring ph1bph1b*2/SDAU 2028)revealed two Fhb7^(+)wheat-Tp7el_(2)L lines,Shannong 2–16and Shannong 16–1,that carry a desired truncated Fhb7^(+)translocation segment without PSY-E2.The two lines show levels of resistance to FHB and FCR similar to those of the original translocation line SDAU 2028,but have white flour.To facilitate Fhb7 use in wheat breeding,STS markers were developed and used to isolate Fhb7 on a truncated Tp7el_(2) translocation segment.Near-isogenic lines carrying the Fhb7^(+)segment were generated in the backgrounds of three commercial cultivars,and Fhb7^(+)lines showed increased FHB and FCR resistance without yield penalty.The breakage of the tight linkage between Fhb7 and PSY-E2 via homoeologous recombination provides genetic resources for improvement of wheat resistance to FHB and FCR and permit the large-scale deployment of Fhb7 in breeding using marker-assisted selection.

Physiological and Morphological Responses of Susceptible and Resistant Barleys to Bird Cherry-Oat Aphid Feeding

The bird cherry-oat aphid (Rhopalosiphum padi [Linnaeus, 1758]) is considered a key pest of cereal crops worldwide, causing direct damage through sap feeding and by acting as a vector for viral diseases. Managing aphids is challenging because of their biology and potential resistance to insecticides. Developing resistant barley genotypes is a sustainable strategy for managing BCOA. In this study, we assessed responses of susceptible “Morex” and resistant “BCO R001” barley, Hordeum vulgare L. genotypes to different initial BCOA densities (0, 50, 100 or 200 aphids.plant-1). Physiological and morphological parameters were measured weekly for four weeks after infestation. Chlorophyll content, photosynthetic rate, plant aerial fresh and dry weight were greater for the resistant cultivar at lower aphid abundances and up to three weeks after infestation. Carbon assimilation curves (A/Ci) of infested “BCO R001” were similar to controls 15 days post infestation, differing from Morex. However, BCOA infestation of 50 aphid.plant-1 for two weeks negatively impacted the fitness of both genotypes. Initial resistance by BCO R001 to BCOA infestation can allow growers and natural enemies more time contributing to more effective and sustainable management of BCOA infestations.

Relevance of Advanced Plant Disease Detection Techniques in Disease and Pest Management for Ensuring Food Security and Their Implication: A Review

Plant diseases and pests present significant challenges to global food security, leading to substantial losses in agricultural productivity and threatening environmental sustainability. As the world’s population grows, ensuring food availability becomes increasingly urgent. This review explores the significance of advanced plant disease detection techniques in disease and pest management for enhancing food security. Traditional plant disease detection methods often rely on visual inspection and are time-consuming and subjective. This leads to delayed interventions and ineffective control measures. However, recent advancements in remote sensing, imaging technologies, and molecular diagnostics offer powerful tools for early and precise disease detection. Big data analytics and machine learning play pivotal roles in analyzing vast and complex datasets, thus accurately identifying plant diseases and predicting disease occurrence and severity. We explore how prompt interventions employing advanced techniques enable more efficient disease control and concurrently minimize the environmental impact of conventional disease and pest management practices. Furthermore, we analyze and make future recommendations to improve the precision and sensitivity of current advanced detection techniques. We propose incorporating eco-evolutionary theories into research to enhance the understanding of pathogen spread in future climates and mitigate the risk of disease outbreaks. We highlight the need for a science-policy interface that works closely with scientists, policymakers, and relevant intergovernmental organizations to ensure coordination and collaboration among them, ultimately developing effective disease monitoring and management strategies needed for securing sustainable food production and environmental well-being.

Single nucleotide polymorphisms linked to quantitative trait loci for grain quality traits in wheat

Wheat(Triticum aestivum L.) grain quality traits that are controlled by quantitative traits loci(QTL) define suitable growing areas and potential end-use products of a wheat cultivar. To dissect QTL for these traits including protein content(GPC); test weight(TW); single kernel characterization system(SKCS)-estimated kernel weight(SKW); kernel diameter(KD);kernel hardness measured by near-infrared reflectance spectroscopy(NIRS) hardness index(NHI); and SKCS-hardness index(SHI), a high-density genetic map with single nucleotide polymorphism(SNP) and simple sequence repeat(SSR) markers was developed using recombinant inbred lines(RILs) derived from Ning7840 × Clark. The RILs were evaluated for these quality traits in seven Oklahoma environments from 2001 to 2003. A total of 41 QTL with additive effects on different traits were mapped on most wheat chromosomes,excluding 1A, 2A, 3D, 4D, 6D, and 7B. Seven chromosome regions showed either tightly linked QTL or QTL with pleiotropic effects on two to four traits. Ten pairs of QTL showed additive × additive effects(AA), four QTL were involved in additive × environment(AE)effects, and one was involved in AAE effects. Two to eleven QTL for each of the six traits and139 tightly linked markers to these QTL were identified. The findings shed light on the inheritance of wheat grain quality traits and provide DNA markers for manipulating these important traits to improve quality of new wheat cultivars.

Medicago truncatula resources to study legume biology and symbiotic nitrogen fixation

Medicago truncatula is a chosen model for legumes towards deciphering fundamental legume biology,especially symbiotic nitrogen fixation.Current genomic resources for M.truncatula include a completed whole genome sequence information for R108 and Jemalong A17 accessions along with the sparse draft genome sequences for other 226 M.truncatula accessions.These genomic resources are complemented by the availability of mutant resources such as retrotransposon(Tnt1)insertion mutants in R108 and fast neutron bombardment(FNB)mutants in A17.In addition,several M.truncatula databases such as small secreted peptides(SSPs)database,transporter protein database,gene expression atlas,proteomic atlas,and metabolite atlas are available to the research community.This review describes these resources and provide information regarding how to access these resources.

Molecular Cytogenetic Characterization and Stem Rust Resistance of Five Wheat-Thinopyrum ponticum Partial Amphiploids

Partial amphiploids created by crossing common wheat （Triticum aestivum L.） and Thinopyrum ponticum （Podp.） Barkworth ＆ D. R. Dewey are important intermediates in wheat breeding because of their resistance to major wheat diseases. In this study, we examined the chromosome compositions of five Xiaoyan-series wheat-Th, ponticum partial amphiploids （Xiaoyan 68, Xiaoyan 693, Xiaoyan 784, Xiaoyan 7430, and Xiaoyan 7631） using GISH, multicolor-GISH, and multicolor-FISH. We found several chromosome changes in these lines. For example, wheat chromosomes 1B and 2B were added in Xiaoyan 68 and Xiaoyan 7430, respectively, while wheat chromosome 6B was eliminated from Xiaoyan 693 and Xiaoyan 7631. Chromosome rearrangements were also detected in these amphiploids, including an interspecific translocation involving chromosome 4D and some intergenomic translocations, such as A--B and A--D translocations, among wheat genomes. Analysis of the Th. ponticum chromosomes in the amphiploids showed that some lines shared the same alien chromosomes. We also evaluated these partial amphiploids for resistance to nine races of stem rust, including TTKSK （commonly known as Ug99）. Three lines, Xiaoyan 68, Xiaoyan 784, and Xiaoyan 7430, exhibited excellent resistance to all nine races, and could therefore be valuable sources of stem rust resistance in wheat breeding.