Common wheat (Triticum aestivum L.) is the world\'s primary food crop, and ensuring its safe production is of utmost importance for global peace and human development. However, the continuous threat of fungal diseases, including Fusarium head scab, rusts, sharp eyespot, and powdery mildew (PM), poses a significant challenge to production. PM caused by Blumeria graminis f. sp. tritici (Bgt) causes substantial yield losses. Heshangmai (HSM), a wheat landrace originating from Sichuan Province, possesses high levels of resistance to PM. A comprehensive study using a large segregating population of a cross between HSM and Ningmaizi119 (NMZ119) revealed a single recessive allele conferring resistance. The gene, provisionally designated PmHSM, was located on the long arm of chromosome 4A (4AL). Molecular marker analysis, PM response array, and an allelism test indicated that PmHSM is a novel recessive resistance gene that shares an allelic relationship with PmHHXM. Thirteen simple sequence repeat (SSR) markers were developed using the sequence information of the 4AL region in the Chinese spring reference sequence v2.1 (CS RefSeq v2.1). PmHSM was flanked by markers Xmp1567 and Xmp1444 at genetic distances of 0.11 cM and 0.18 cM, respectively, and co-segregated with markers Xmp1439/Xmp1440/Xmp1442.

Fruit peel color is a major factor that influences fruit quality and customers\' demand. However, the molecular mechanisms underlying the green fruit peel color trait of Cucurbita pepo L. remain unknown. Two parental lines, RP16 and RP38, were used to study the fruit peel color trait in C. pepo. The parental line RP16 shows white peel color, whereas RP38 exhibits green peel color. 384 F2 populations were used to identify the inheritance pattern associated with green fruit and white fruit peel in Cucurbita pepo L. 293 F2 individuals were white, and 91 F2 individuals were green, resulting in a ratio of 3:1. Hence, white peel is dominant over the green fruit peel trait, and a single recessive green peel gene (Cpgp) controls the green fruit peel. The fruit chlorophyll (Chll) content decreases as fruit matures in the RP16 line. In contrast, Chll increases during the fruit growing periods on fruit peels of the RP38 line. The BSA-sequence analysis revealed the Cpgp locus on Chr5, within a 2.3 Mb region. Subsequent fine-mapping analysis, using 699 F2 plants, narrowed down this region to 23.90 kb on the same chromosome. Within this region, two annotated genes, namely Cp4.1LG05g02070 and Cp4.1LG05g02060, are present. These genes are predicted to encode a two-component Arabidopsis Pseudo-Response Regulator 2-like protein (APRR2), which may be involved in green pigmentation processes in plants. Consequently, sequence alignment and gene expression analyses at various fruit development stages supported that Cp4.1LG05g02070 may be the primary candidate gene responsible for regulating the green fruit peel color trait in Cucurbita pepo L. This study may provide a basis for further study on the basic mechanisms that control the fruit peel colors in Cucurbita spp.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s11032-024-01492-7.

Wheat (Triticum aestivum L.) is one of the most important crops worldwide. Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is a destructive disease threatening wheat yield and quality. The utilization of resistant genes and cultivars is considered the most economical, environmentally-friendly, and effective method to control powdery mildew. Wheat breeding line Jingzi 102 was highly resistant to powdery mildew at both seedling and adult plant stages. Genetic analysis of F1, F2, and F2:3 populations of \"Jingzi 102 × Shixin 828\" showed that the resistance of Jingzi 102 against powdery mildew isolate E09 at the seedling stage was controlled by a single dominant gene, temporarily designated PmJZ. Using bulked segregant RNA-Seq combined with molecular markers analysis, PmJZ was located on the long arm of chromosome 2B and flanked by markers BJK695-1 and CIT02g-20 with the genetic distances of 1.2 and 0.5 cM, respectively, corresponding to the bread wheat genome of Chinese Spring (IWGSC RefSeq v2.1) 703.8-707.6 Mb. PmJZ is most likely different from the documented Pm genes on chromosome 2BL based on their physical positions, molecular markers analysis, and resistance spectrum. Based on the gene annotation information, five genes related to disease resistance could be considered as the candidate genes of PmJZ. To accelerate the application of PmJZ, the flanking markers BJK695-1 and CIT02g-20 can serve for marker-assisted selection of PmJZ in wheat disease resistance breeding.

Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici (Bgt), is one of the most devastating diseases affecting wheat throughout the world. Breeding and growing resistant wheat cultivars is one of the most economic and effective methods to control the disease, and as such, identifying and mapping the new and effective resistance genes is critical. Baidatou, a Chinese wheat landrace, shows excellent field resistance to powdery mildew. To identify the resistance gene(s) in Baidatou, 170 F7:8 recombinant inbred lines (RILs) derived from the cross Mingxian 169/Baidatou were evaluated for powdery mildew response at the adult-plant stage in the experimental fields in Yangling (YL) of Shaanxi Province and Tianshui (TS) in Gansu Province in 2019, 2020, and 2021. The relative area under disease progress curve (rAUDPC) of Mingxian 169/Baidatou F7:8 RILs indicated that the resistance of Baidatou to powdery mildew was controlled by quantitative trait loci (QTLs). Based on bulk segregation analysis combined with the 660K single nucleotide polymorphism (SNP) array and genotyping by target sequencing (16K SNP) of the entire RIL population, two QTLs, QPmbdt.nwafu-2AS and QPmbdt.nwafu-3AS, were identified, and these accounted for up to 44.5% of the phenotypic variation. One of the QTLs was located on the 3.32 cM genetic interval on wheat chromosome 2AS between the kompetitive allele-specific PCR markers AX-111012288 and AX_174233809, and another was located on the 9.6 cM genetic interval on chromosome 3AS between the SNP markers 3A_684044820 and 3A_686681822. These markers could be useful for successful breeding of powdery mildew resistance in wheat.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a severe disease that affects the yield and quality of wheat. Popularization of resistant cultivars in production is the preferred strategy to control this disease. In the present study, the Chinese wheat breeding line Jimai 809 showed excellent agronomic performance and high resistance to powdery mildew at the whole growth stage. To dissect the genetic basis for this resistance, Jimai 809 was crossed with the susceptible wheat cultivar Junda 159 to produce segregation populations. Genetic analysis showed that a single dominant gene, temporarily designated PmJM809, conferred the resistance to different Bgt isolates. PmJM809 was then mapped on the chromosome arm 2BL and flanked by the markers CISSR02g-1 and CIT02g-13 with genetic distances 0.4 and 0.8 cM, respectively, corresponding to a physical interval of 704.12-708.24 Mb. PmJM809 differed from the reported Pm genes on chromosome arm 2BL in origin, resistance spectrum, physical position and/or genetic diversity of the mapping interval, also suggesting PmJM809 was located on a complex interval with multiple resistance genes. To analyze and screen the candidate gene(s) of PmJM809, six genes related to disease resistance in the candidate interval were evaluated their expression patterns using an additional set of wheat samples and time-course analysis post-inoculation of the Bgt isolate E09. As a result, four genes were speculated as the key candidate or regulatory genes. Considering its comprehensive agronomic traits and resistance findings, PmJM809 was expected to be a valuable gene resource in wheat disease resistance breeding. To efficiently transfer PmJM809 into different genetic backgrounds, 13 of 19 closely linked markers were confirmed to be suitable for marker-assisted selection. Using these markers, a series of wheat breeding lines with harmonious disease resistance and agronomic performance were selected from the crosses of Jimai 809 and several susceptible cultivars.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s11032-024-01467-8.

Low temperature and cold damage are natural factors that seriously reduce wheat yield. Thus, how to improve the cold resistance of wheat has been the focus of wheat breeders and geneticists. However, the genetic improvement for this trait has been slow, mainly because cold resistance is a complex quantitative trait and field phenotypic identification is relatively difficult. Therefore, the discovery, mapping, and cloning of the cold resistance genes of wheat provide a theoretical basis for the genetic improvement of wheat against cold resistance and facilitate the analysis of the molecular mechanisms of cold resistance in wheat. This study used the wheat line H261 and its EMS mutants LF2099 and XiNong 239 as materials. Cold trait segregation occurred in the F2 generation of mutants LF2099 and XiNong 239 at a 15:1 separation ratio. Genetic analysis showed that two dominant overlapping genes, temporarily named Wcr-3 and Wcr-4, control cold resistance in wheat. Furthermore, a combined BSA and SNP array established that Wcr-3 is between BU100519 (SSR marker) and AX-94843669 (SNP marker). The markers are 1.32 cM apart, corresponding to the 5.41 Mb physical interval on the Chinese Spring 2B chromosome with 67 functionally annotated genes. Wcr-4 is located between AX-94657955 (SNP marker) and LC-23 (SSR marker), which are 1.79 cM apart, corresponding to a 2.35 Mb physical interval on the Chinese Spring 2D chromosome, which contains 66 functionally annotated genes. Wcr-3 and Wcr-4 are two new cold resistance genes, laying the foundation for their fine mapping and cloning.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s11032-023-01425-w.

Wheat leaf rust (Lr), which is caused by Puccinia triticina Eriks. (Pt), is one of the most important wheat diseases affecting wheat production globally. Using resistant wheat cultivars is the most economical and environmentally friendly way to control leaf rust. The Italian wheat cultivar Libellula has demonstrated good resistance to Lr in field studies. To identify the genetic basis of Lr resistance in \'Libellula\', 248 F6 recombinant inbred lines from the cross \'Libellula\'/\'Huixianhong\' was phenotyped for Lr severity in seven environments: the 2014/2015, 2016/2017, 2017/2018, and 2018/2019 cropping seasons at Baoding, Hebei Province, and the 2016/2017, 2017/2018, and 2018/2019 crop seasons at Zhoukou, Henan Province. Bulked segregant analysis and simple sequence repeat markers were then used to identify the quantitative trait loci (QTLs) for Lr adult-plant resistance in the population. Six QTLs were consequently detected and designated as QLr.hebau-1AL and QLr.hebau-1AS that were presumed to be new and QLr.hebau-1BL, QLr.hebau-3AL, QLr.hebau-4BL, and QLr.hebau-7DS that were identified at similar physical positions as previously reported QTLs. Based on chromosome positions and molecular marker tests, QLr.hebau-1BL and QLr.hebau-7DS share similar flanking markers with Lr46 and Lr34, respectively. Lr46 and Lr34 are race nonspecific adult plant resistance (APR) genes for leaf rust and stripe rust and powdery mildew. QLr.hebau-4BL showed multiple disease resistance to leaf rust, stripe rust, Fusarium head blight, and powdery mildew. The QTL identified in this study, as well as their closely linked markers, may potentially be used in marker-assisted selection in wheat breeding.

Mass spectrometry imaging (MSI) is a sensitive, specific, label-free imaging analysis technique that can simultaneously obtain the spatial distribution, relative content, and structural information of hundreds of biomolecules in cells and tissues, such as lipids, small drug molecules, peptides, proteins, and other compounds. The study of molecular mapping of single cells can reveal major scientific issues such as the activity pattern of living organisms, disease pathogenesis, drug-targeted therapy, and cellular heterogeneity. Applying MSI technology to the molecular mapping of single cells can provide new insights and ideas for the study of single-cell metabolomics. This review aims to provide an informative resource for those in the MSI community who are interested in single-cell imaging. Particularly, we discuss advances in imaging schemes and sample preparation, instrumentation improvements, data processing and analysis, and 3D MSI over the past few years that have allowed MSI to emerge as a powerful technique in the molecular imaging of single cells. Also, we highlight some of the most cutting-edge studies in single-cell MSI, demonstrating the future potential of single-cell MSI. Visualizing molecular distribution at the single-cell or even sub-cellular level can provide us with richer cell information, which strongly contributes to advancing research fields such as biomedicine, life sciences, pharmacodynamic testing, and metabolomics. At the end of the review, we summarize the current development of single-cell MSI technology and look into the future of this technology.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a serious fungal disease that critically threatens the yield and quality of wheat. Utilization of host resistance is the most effective and economical method to control this disease. In our study, a wheat breeding line ShiCG15-009, released from Hebei Province, was highly resistant to powdery mildew at all stages. To dissect its genetic basis, ShiCG15-009 was crossed with the susceptible cultivar Yannong 21 to produce F1, F2 and F2:3 progenies. After genetic analysis, a single dominant gene, tentatively designated PmCG15-009, was proved to confer resistance to Bgt isolate E09. Further molecular markers analysis showed that PmCG15-009 was located on chromosome 2BL and flanked by markers XCINAU130 and XCINAU143 with the genetic distances 0.2 and 0.4 cM, respectively, corresponding to a physic interval of 705.14-723.48 Mb referred to the Chinese Spring reference genome sequence v2.1. PmCG15-009 was most likely a new gene differed from the documented Pm genes on chromosome 2BL since its different origin, genetic diversity, and physical position. To analyze and identify the candidate genes, six genes associated with disease resistance in the candidate interval were confirmed to be associated with PmCG15-009 via qRT-PCR analysis using the parents ShiCG15-009 and Yannong 21 and time-course analysis post-inoculation with Bgt isolate E09. To accelerate the transfer of PmCG15-009 using marker-assisted selection (MAS), 18 closely or co-segregated markers were evaluated and confirmed to be suitable for tracing PmCG15-009, when it was transferred into different wheat cultivars.

Hull color of foxtail millet is an important indicator of certain nutritional quality parameters. An F2:6 recombinant inbred line (RIL) population developed by crossing a yellow-hulled cultivar Yugu 5 and a brown-hulled cultivar Jigu 31 was used to determine the genetic control of the hull color trait. This population segregated for yellow and brown hull colors in a ratio of 2:1, indicating that hull color is regulated by multiple genetic loci. A bulk segregant analysis-RNA sequencing (BSR-Seq) approach performed using the RNA bulks from 30 lines with brown and yellow hull colors each identified three genomic regions on chromosomes 1 (4,570,517-10,698,955 bp), 2 (40,301,380-46,168,003 bp), and 3 (44,469,860-50,532,757 bp). A new QTL for brown hull color of Jigu 31, QHC.czas1, was detected between bin markers Block43 and Block697 on chromosome 1 with the genetic linkage map constructed by re-sequencing a subset of the 147 RILs. This QTL explained a high level of phenotypic variation ranging from 28.0% to 47.0%. The corresponding genomic region of this QTL in the foxtail millet reference genome overlapped with that detected on chromosome 1 by the BSR-Seq analysis. Nineteen genes associated with biosynthesis of anthocyanin were annotated in this genomic region. Gene Si1g06530 encoding a SANT/Myb domain protein was highly expressed in developing panicles and seeds, which warrants further verification as the candidate gene for the brown color hull of Jigu 31. Moreover, several annotated genes for biosynthesis of anthocyanin were identified in the genomic regions of chromosomes 2 and 3.