A longtime favorite paint marker used by manufacturers for marking parts and products. Diagraph GP-X yellow paint markers are made to write on a variety of surfaces including metal pipe, PVC, barrels, pallets and lumber. GP-X Classic Paint Markers come in 12 different colors - great for making color coded marks on parts.
Yellow Markers
Download Zip: https://urlcod.com/2vzogs
Used by manufacturers for marking and color coding parts and products. Diagraph GP-X yellow paint markers are made to write on a variety of surfaces including metal pipe, PVC, barrels, pallets and lumber.
Tomato yellow leaf curl virus (TYLCV) is a disease that is damaging to tomato production worldwide. Resistance to TYLCV has been intensively investigated, and single resistance genes such as Ty-1 have been widely deployed in breeding programs. However, resistance-breaking incidences are frequently reported, and achieving durable resistance against TYLCV in the field is important. In this study, gene-specific markers for Ty-2 and ty-5, and closely-linked markers for Ty-4 were developed and applied to distinguish TYLCV resistance in various tomato genotypes. Quantitative infectivity assays using both natural infection in the field and artificial inoculation utilizing infectious TYLCV clones in a growth chamber were optimized and performed to investigate the individual and cumulative levels of resistance. We confirmed that Ty-2 could also be an effective source of resistance for TYLCV control, together with Ty-1. Improvement of resistance as a result of gene-pyramiding was speculated, and breeding lines including both Ty-1 and Ty-2 showed the strongest resistance in both field and artificial infections.
Sugarcane yellow leaf (SCYL), caused by the sugarcane yellow leaf virus (SCYLV) is a major disease affecting sugarcane, a leading sugar and energy crop. Despite damages caused by SCYLV, the genetic base of resistance to this virus remains largely unknown. Several methodologies have arisen to identify molecular markers associated with SCYLV resistance, which are crucial for marker-assisted selection and understanding response mechanisms to this virus. We investigated the genetic base of SCYLV resistance using dominant and codominant markers and genotypes of interest for sugarcane breeding. A sugarcane panel inoculated with SCYLV was analyzed for SCYL symptoms, and viral titer was estimated by RT-qPCR. This panel was genotyped with 662 dominant markers and 70,888 SNPs and indels with allele proportion information. We used polyploid-adapted genome-wide association analyses and machine-learning algorithms coupled with feature selection methods to establish marker-trait associations. While each approach identified unique marker sets associated with phenotypes, convergences were observed between them and demonstrated their complementarity. Lastly, we annotated these markers, identifying genes encoding emblematic participants in virus resistance mechanisms and previously unreported candidates involved in viral responses. Our approach could accelerate sugarcane breeding targeting SCYLV resistance and facilitate studies on biological processes leading to this trait.
One of the diseases that affect this crop is sugarcane yellow leaf (SCYL), which is caused by sugarcane yellow leaf virus (SCYLV), a positive-sense ssRNA virus belonging to the Polerovirus genus9,10. The expression of SCYL symptoms is complex and usually occurs in late stages of plant development, being mainly characterized by the intense yellowing of midribs in the abaxial surface of leaves11,12. SCYLV alters the metabolism and transport of sucrose and photosynthetic efficiency13,14, impairing plant development, which eventually reflects in productivity losses15,16,17,18,19,20. Many SCYL symptoms may, however, be caused by other stresses or plant senescence12,15,21, making SCYL identification troublesome. Therefore, molecular diagnosis of SCYLV infection is of great importance; this was initially performed through immunological assays11, but more sensitive and accurate methods using reverse transcription followed by quantitative polymerase chain reaction (RT-qPCR) were later developed18,22,23.
Here, we evaluated the efficacy of several genome-wide approaches to identify markers and genes associated with SCYLV resistance. We analyzed a panel of Saccharum accessions inoculated with SCYLV, which were graded for the severity of SCYL symptoms, and their viral titer was estimated by relative and absolute RT-qPCR. This panel was genotyped with amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs), as well as single nucleotide polymorphisms (SNPs) and insertions and deletions (indels) obtained by genotyping-by-sequencing (GBS). We then employed three distinct methodologies to detect marker-trait associations: the fixed and random model circulating probability unification (FarmCPU) method using dominant AFLPs and SSRs; mixed linear modeling using SNPs and indels, in which allele proportions (APs) in each locus were employed to establish genotypic classes and estimate additive and dominant effects; and several machine learning (ML) methods coupled with feature selection (FS) techniques, using all markers to predict genotype attribution to phenotypic clusters. Finally, we annotated genes containing markers associated with phenotypes, discussing the putative participation of these genes in the mechanisms underlying resistance to SCYLV.
Out of the 362 nonredundant markers associated with all phenotypes, 176 were located in genic regions and could be annotated by aligning their 2000-bp neighboring regions with the coding sequences (CDSs) of 14 Poaceae species and Arabidopsis thaliana genomes; Supplementary Table 15 contains data on the alignment with the highest percentage of identity for each marker. In some cases, where two or more markers were closely located, coincident alignments and annotations were obtained; consequently, 148 genes were representative of all the best alignments. The large majority of top-scoring alignments (117) occurred with CDSs of Sorghum bicolor, the phylogenetically closest species among those used for alignment. Fewer alignments also occurred with the CDSs of other species. Several of the annotated genes could be associated with plant resistance to viruses, as detailed in the discussion.
However, we observed no quantitative correlation between the severity of SCYL symptoms and SCYLV titers across the sugarcane genotypes analyzed. This finding corroborates a growing body of evidence suggesting that these traits are not strongly or necessarily correlated, i.e., high SCYLV titers are not a guarantee of more severe yellowing or of its development at all37,38,39. This reinforces the importance of SCYLV molecular screening of sugarcane clones by breeding programs, in an effort to avoid the employment of genotypes that accumulate high viral loads asymptomatically but may inconspicuously suffer yield losses as well as serving as a virus reservoir for vector transmission to other susceptible genotypes.
Our main objective was, however, to identify markers associated with SCYLV resistance in a broader sense. With this aim, we performed genotyping with a combination of dominant and codominant markers, which has never been described for sugarcane. We evaluated the impact of using genomic references from various backgrounds in variant calling from GBS. In previous sugarcane GWASs, this was performed using the genome of S. bicolor31,44,45,46, a close relative species with a well-assembled and annotated genome. However, in our analyses, this reference yielded a number of markers considerably inferior to other references. The methyl-filtered genome of the SP70-1143 cultivar yielded the most markers, in agreement with a previous study employing GBS47; this is a plausible outcome, as this method avoids sampling of methylated regions48 which were also filtered out for this genomic assembly49. However, to choose the best reference for further analyses, we also considered the quality of the assembly, which greatly affects the results of GWASs in polyploids50. The best-assembled sugarcane genome available to date is the allele-defined genome of a haploid S. spontaneum accession51. Despite presenting one of the highest total tag alignment rates, this reference also gave a very high rate of multiple alignments, leading to the identification of relatively few markers. This was probably due to the alignment of tags to hom(e)ologous regions of different alleles rather than to the duplicated regions that we intended to avoid. To circumvent this situation, we conducted our analyses with markers isolated using a monoploid chromosome set obtained from this genome, which provided a large number of markers with reliable position information.
We annotated 176 markers associated with SCYLV resistance to 148 genes. Many candidates do not allow extensive discussion on their involvement in resistance to this disease, as they either have very generic descriptions or have not been previously linked to plant virus resistance. Other proteins have occasionally been associated with responses to viruses but are members of very large gene families with extremely diverse biological roles and will not be discussed. Remarkably, few candidates encode proteins previously associated with the response to SCYLV infection. This was the case for SbRio.10G317500.1, encoding a peroxidase precursor. Peroxidases are long known to be activated in response to pathogens, but most notably, a guaiacol peroxidase has been shown to be more active in sugarcane plants exhibiting SCYL symptoms than in uninfected or asymptomatic plants85. Our results provide further evidence that these enzymes are in fact involved in the response to SCYLV. Other candidates harboring markers associated with SCYLV resistance encode proteins with motifs previously associated with SCYLV resistance31: Sobic.001G023900, encoding a GATA zinc finger protein, and Sobic.001G200200 and Zm00001d037864_T030, both of which encode proteins containing tetratricopeptide repeats. 2ff7e9595c
Comments