Plant Genome最新文献

MicroRNAs (miRNAs) control gene expression in plant through transcript cleavage and translation inhibition. Recently, 24-nt miRNAs have been shown to direct DNA methylation at target sites, regulating the neighboring gene expression. Our study focused on miR9560, a 24-nt miRNA induced by cadmium (Cd) stress in Brassica rapa ssp. parachinensis (B. parachinensis). Phylogenetic analysis revealed miR9560 predominantly emerged in the Rosanae superorder and was conserved in Brassicaceae, with potential target sites adjacent to transporter family genes HMAs. RNA gel blotting showed that mature miR9560 was only detected in various Brassica crops roots after Cd stress. In B. parachinensis, miR9560's putative target site is upstream of BrpHMA2, an afflux-type Cd transporter. In a transient expression system of B. parachinensis protoplasts, the expression of miR9560 increased the DNA methylation upstream of BrpHMA2, reducing the transcription of BrpHMA2. This regulation was also observed in Arabidopsis wild-type protoplasts but not in the mutants dcl234 and ago4 with impairments in the RNA-dependent DNA methylation (RdDM) pathway. We deduced that miR9560 modulates BrpHMA2 expression via the RdDM pathway, potentially regulating Cd uptake and movement in B. parachinensis. Furthermore, this regulatory mechanism may extend to other Brassica plants. This study enhances our comprehension of 24-nt miRNAs role in regulating Cd accumulation within Brassica plants.

White mold, caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary, is a devastating disease affecting common bean (Phaseolus vulgaris L.) production worldwide. Breeding for resistance to white mold is challenging due to its quantitative inheritance and intricate genetic mechanisms. This research aimed to validate and characterize physiological resistance in the pinto dry bean market class through greenhouse straw tests under controlled conditions and field assessments under natural environments. Classical quantitative trait locus (QTL) mapping and Khufu de novo QTL-seq were employed to detect and narrow QTL intervals and identify candidate genes associated with white mold resistance in two pinto bean recombinant inbred line populations, PT9-5-6/USPT-WM-12 (P2) and PT12-37/VCP-13 (P3). Eleven QTL, five in P2 and six in P3, conditioning white mold resistance were identified. New QTL were discovered including WM1.4 and WM11.5 in P2, and WM1.5 and WM7.7 in P3. Existing major-effect QTL were validated: WM5.4 (34%-phenotypic variation explained) and WM7.4 (20%) in straw tests, and WM2.2 (15%) and WM3.1 (27%) under field conditions. QTL for avoidance traits such as resistance to lodging and late maturity overlapped WM2.2 in P2 and WM1.5, WM3.1, WM5.4, and WM7.7 in P3. WM5.4 (Pv05: 7.0-38.7 Mb) was associated with a large Phaseolus coccineus L. genome introgression in the resistant parent VCP-13. These findings offer narrowed genomic intervals and putative candidate genes for marker-assisted selection targeting white mold resistance improvement in pinto beans.

The perennial grass Thinopyrum intermedium (intermediate wheatgrass [IWG]) is being domesticated as a food crop. With a deep root system and high biomass, IWG can help reduce soil and water erosion and limit nutrient runoff. As a novel grain crop undergoing domestication, IWG lags in yield, seed size, and other agronomic traits compared to annual grains. Better characterization of trait variation and identification of genetic markers associated with loci controlling the traits could help in further improving this crop. The University of Minnesota's Cycle 5 IWG breeding population of 595 spaced plants was evaluated at two locations in 2021 and 2022 for agronomic traits plant height, grain yield, and spike weight, and domestication traits shatter resistance, free grain threshing, and seed size. Pairwise trait correlations were weak to moderate with the highest correlation observed between seed size and height (0.41). Broad-sense trait heritabilities were high (0.68-0.77) except for spike weight (0.49) and yield (0.44). Association mapping using 24,284 genome-wide single nucleotide polymorphism markers identified 30 main quantitative trait loci (QTLs) across all environments and 32 QTL-by-environment interactions (QTE) at each environment. The genomic prediction model significantly improved predictions when parents were used in the training set and significant QTLs and QTEs used as covariates. Seed size was the best predicted trait with model predictive ability (r) of 0.72; yield was predicted moderately well (r = 0.45). We expect this discovery of significant genomic loci and mostly high trait predictions from genomic prediction models to help improve future IWG breeding populations.

Wheat breeders are constantly looking for genes and alleles that increase grain yield. One key strategy is finding new genetic resources in the wild and domesticated gene pools of related species with genes affecting grain size. This study explored a natural population of Triticum turgidum (L.) phenotyped for grain weight and size-related traits in three field trials and genotyped with single nucleotide polymorphism markers spread across the entire genome. The genome-wide association study analysis identified 39 quantitative trait loci (QTL) for 1000-kernel weight, grain length, grain width, grain area, and grain aspect consistent in at least two and across environments. Interestingly, 23 QTL for grain-related traits were grouped in nine QTL clusters located on chromosomes 1A, 1B, 2B, 3B, 4B, 5A, and 6B, respectively. Moreover, most of these QTL support findings from previous QTL analyses and are further strengthened by the known functions of the genes (such as BG2, GS5, and SRS3) and their similarity to genes in other cereal species. QTL clusters harbored genes that participate in various metabolic processes potentially involved in seed development, phytohormone signaling, sugar transport, mitogen-activated protein kinases signaling, and transcriptional factors (such as MADS-box and WRKY). Identifying loci controlling grain-related traits will provide information on the genetic resources available to breeders to improve grain yield, as well as the opportunity to develop close gene markers to be used in marker-assisted selection programs.

Meiosis and recombination lead to gametes with novel combinations of genes as key processes in evolution and plant breeding. Numerous extrinsic factors have been reported to affect meiotic recombination of plants. The goal of this research was to identify simple, low-cost, and effective treatments that affect recombination in maize (Zea mays L.). The treatments, water-deficit stress and defoliation, were separately applied to two F1-generation genotypes, B73/Mo17 and Mo17/H99. The F1 plants were backcrossed to an inbred line to produce the backcross populations that were genotyped at microsatellite loci on chromosomes 1 and 10. Overall, 1271 crossovers were observed in the progeny of the water-stressed plants while 1092 were observed in the progeny of the non-stressed plants. The water-deficit treatment may have increased the rates of recombination in both F1 genotypes while the defoliation treatment was ineffective.

Tryptophan decarboxylase (TDC) belongs to a family of aromatic amino acid decarboxylases and catalyzes the conversion of tryptophan to tryptamine. It is the enzyme involved in the first step of melatonin (MT) biosynthesis and mediates several key functions in abiotic stress tolerance. In Oryza sativa under pesticide-induced stress, TDC function is unclear. Three TDC differentially expressed genes (DEGs) and six TDC-coding genes were found to be expressed in fluroxypyr-meptyl (FLUME)-treated rice transcriptome datasets, which allowed researchers to explore the properties and roles of rice TDC family genes under pesticide-induced stress. By applying sequence alignment and phylogenetic analysis, two subfamilies of the TDC gene family-DUF674 and AAT_I-were found in rice, Glycine max, Zea mays, Hordeum vulgare, and Solanum lycopersicum. According to chromosomal location studies, segmental duplication aided in the expansion of the OsTDC gene family, and the three TDC DEGs in rice were irregularly distributed on two of its 12 chromosomes. In addition, nine rice TDC genes displayed a collinear relationship with those of soybean, maize, barley, and tomato. Rice TDC genes can encode a variety of biotic and abiotic stress responses because of their diverse gene architectures, cis-elements, motif compositions, and conserved domains. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis confirmed that a proportion of TDC genes (Os08g0140300, Os08g0140500, and Os10g0380800) were preferably expressed under 0.08 mg L^-1 FLUME stress, with a 5.2-, 3.2-, and 3.9-fold increase in roots and a 2.1-, 2.4-, and 2.6-fold increase in shoots, respectively. MT treatment further increased the expression of these genes, with a 2.1-fold, 3.1-fold, and fivefold increase in roots and a 1.5-, 1.1-, and 1.1-fold increase in shoots than that treated with 0.08 mg L^-1 FLUME only, respectively. When rice seedling roots and shoots were subjected to 0.08 mg L^-1 FLUME stress, TDC activity was increased by 2.7 and 1.6 times higher than in the control, respectively. MT application also further promoted TDC activity in rice tissues; TDC activity in rice roots and shoots was twofold and 1.4-fold higher, respectively, than that under 0.08 mg L^-1 FLUME alone. These findings indicate that TDC genes respond effectively to FLUME stress, and the application of MT could enhance the expression of these TDC genes, which comprise a set of candidate genes that regulate pesticide metabolism and degradation with the application of MT.

Leaf rust, caused by Puccinia triticina (Pt), poses a constant threat to global wheat production, and novel leaf rust resistance genes are needed to combat the disease. A previous genome-wide association study (GWAS) identified a single nucleotide polymorphism (SNP) marker associated with leaf rust resistance in the terminal region of chromosome arm 5BS in the Iranian landrace PI 622111. An F₂ population and 175 F_2:3 families from cross PI 622111 × Yuanyu 3 were evaluated for response to Pt isolate Pt52-2 (MMPSD). Genotyping-by-sequencing analysis and genotyping of a subset of the F₂ plants identified 32 SNPs closely associated with leaf rust resistance in the target region. Some of these SNPs were converted into kompetitive allele-specific polymorphic (KASP) markers and used to genotype the F₂ population together with a set of simple sequence repeat (SSR) markers also located in the target genomic region. Linkage analysis delimited the leaf rust resistance gene in PI 622111, designated Lr622111, to a 0.4 Mb interval flanked by Xstars700 (7.22 Mb) and Xstars678 (7.62 Mb) in IWGSC RefSeq v.2.1. An allelism test involving 811 F₂ plants indicated that Lr622111 was allelic to Lr52. Since PI 622111 reacted differently from the Lr52 donor to Pt races in the GWAS, Lr622111 is considered a new Lr52 allele conferring a wide spectrum of resistance to current US Pt races. KASP marker Xstars-KASP239, which is 0.9 cM distal to Lr622111, can be widely used to tag Lr622111 in breeding populations.

Barley yellow dwarf (BYD) is one of the most serious viral diseases in cereal crops worldwide. Identification of quantitative trait loci (QTLs) underlining wheat resistance to barley yellow dwarf virus (BYDV) is essential for breeding BYDV-tolerant wheat cultivars. In this study, a recombinant inbred line (RIL) population was developed from the cross between Jagger (PI 593688) and a Jagger mutant (JagMut1095). A linkage map of 3106 cM consisting of 21 wheat chromosomes was developed using 1003 unique single nucleotide polymorphisms (SNPs) from the RIL population and was used to identify QTLs for BYDV resistance and yield-related traits, including 1000-kernel weight (TKW), kernel area (KA), kernel width (KW), and kernel length (KL). QByd.hwwg-2DL, a QTL on chromosome arm 2DL for BYDV resistance, was consistently identified in three field experiments and explained 11.6%-44.5% of the phenotypic variation. For yield-related traits, six major and repeatable QTLs were identified on 1AS (QKa.hwwg-1AS), 2DL (QTkw.hwwg-2DL, QKa.hwwg-2DL, QKw.hwwg-2DL, and QKl.hwwg-2DL), and 5AL (QKw.hwwg-5AL). The major QTLs on chromosome 2DL for TKW, KA, KW, and KL were mapped between 621 and 643 Mb, overlapping with QByd.hwwg-2DL with all the favorable alleles from Jagger. This study reports the first native BYDV resistance QTL (QByd.hwwg-2DL) originating from common wheat and tightly linked markers to the QTL for improvement of wheat BYDV resistance in wheat breeding.

Climate change represents a significant challenge to global food security by altering environmental conditions critical to crop growth. Plant breeders can play a key role in mitigating these challenges by developing more resilient crop varieties; however, these efforts require significant investments in resources and time. In response, it is imperative to use current technologies that assimilate large biological and environmental datasets into predictive models to accelerate the research, development, and release of new improved varieties that can be more resilient to the increasingly variable climatic conditions. Leveraging large and diverse datasets can improve the characterization of phenotypic responses due to environmental stimuli and genomic pulses. A better characterization of these signals holds the potential to enhance our ability to predict trait performance under changes in weather and/or soil conditions with high precision. This paper introduces characterization and integration of driven omics (CHiDO), an easy-to-use, no-code platform designed to integrate diverse omics datasets and effectively model their interactions. With its flexibility to integrate and process datasets, CHiDO's intuitive interface allows users to explore historical data, formulate hypotheses, and optimize data collection strategies for future scenarios. The platform's mission emphasizes global accessibility, democratizing statistical solutions for situations where professional ability in data processing and data analysis is not available.

End-use and processing traits in wheat (Triticum aestivum L.) are crucial for varietal development but are often evaluated only in the advanced stages of the breeding program due to the amount of grain needed and the labor-intensive phenotyping assays. Advances in genomic resources have provided new tools to address the selection for these complex traits earlier in the breeding process. We used association mapping to identify key variants underlying various end-use quality traits and evaluate the usefulness of genomic prediction for these traits in hard red spring wheat from the Northern United States. A panel of 383 advanced breeding lines and cultivars representing the diversity of the University of Minnesota wheat breeding program was genotyped using the Illumina 90K single nucleotide polymorphism array and evaluated in multilocation trials using standard assessments of end-use quality. Sixty-three associations for grain or flour characteristics, mixograph, farinograph, and baking traits were identified. The majority of these associations were mapped in the vicinity of glutenin/gliadin or other known loci. In addition, a putative novel multi-trait association was identified on chromosome 6AL, and candidate gene analysis revealed eight genes of interest. Further, genomic prediction had a high predictive ability (PA) for mixograph and farinograph traits, with PA up to 0.62 and 0.50 in cross-validation and forward prediction, respectively. The deployment of 46 markers from GWAS to predict dough-rheology traits yielded low to moderate PA for various traits. The results of this study suggest that genomic prediction for end-use traits in early generations can be effective for mixograph and farinograph assays but not baking assays.