Genetic mapping with allele dosage information in tetraploid Urochloa decumbens (Stapf) R.D. Webster reveals insights into spittlebug (Notozulia entreriana Berg) resistance

Ferreira, R. C. U.; Lara, L. A. d. C.; Chari, L.; Barrios, S. C. L.; do Valle, C. B.; Valerio, J. R.; Torres, F. Z. V.; Garcia, A. A. F.; de Souza, A. P.

doi:10.1101/360594

bioRxiv · 10.1101/360594

Genetic mapping with allele dosage information in tetraploid Urochloa decumbens (Stapf) R.D. Webster reveals insights into spittlebug (Notozulia entreriana Berg) resistance

Ferreira, R. C. U.·Lara, L. A. d. C.·Chari, L.·Barrios, S. C. L.·do Valle, C. B.·Valerio, J. R.·Torres, F. Z. V.·Garcia, A. A. F.·de Souza, A. P.

View original source ↗Export metadata ↓

Abstract

Urochloa decumbens (Stapf) R.D. Webster is one of the most important African forage grasses in Brazilian beef production. Currently available genetic-genomic resources for this species are restricted mainly due to polyploidy and apomixis. Therefore, crucial genomic-molecular studies such as the construction of genetic maps and the mapping of quantitative trait loci (QTLs) are very challenging and consequently affect the advancement of molecular breeding. The objectives of this work were to (i) construct an integrated U. decumbens genetic map for a full-sibling progeny using GBS-based markers with allele dosage information, (ii) detect QTLs for spittlebug (Notozulia entreriana) resistance, and (iii) seek putative candidate genes involved in resistance/defense against pathogens. We used the Setaria viridis genome as reference to align GBS reads and selected 4,240 high-quality SNPs markers with allele dosage information. Of these markers, 1,000 were distributed throughout nine homologous groups with a cumulative map length of 1,335.09 cM and an average marker density of 1.33 cM. We detected QTLs for resistance to spittlebug, an important pasture insect pest, that explained between 4.66% and 6.24% of the phenotypic variation. These QTLs are in regions containing putative candidate genes related to resistance/defense against pathogens. Because this is the first genetic map with SNP autotetraploid dosage data and QTL detection in U. decumbens, it will be useful for future evolutionary studies, genome assembly, and other QTL analyses in Urochloa spp. Moreover, the results might facilitate the isolation of spittlebug-related candidate genes and help clarify the mechanism of spittlebug resistance. These approaches will improve selection efficiency and accuracy in U. decumbens molecular breeding and shorten the breeding cycle.

Source connections

Published article ↗

Explore related subjects

plant biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Ferreira, R. C. U., Lara, L. A. d. C., Chari, L., Barrios, S. C. L., do Valle, C. B., Valerio, J. R., Torres, F. Z. V., Garcia, A. A. F., de Souza, A. P.. 2018-07-02. Genetic mapping with allele dosage information in tetraploid Urochloa decumbens (Stapf) R.D. Webster reveals insights into spittlebug (Notozulia entreriana Berg) resistance. https://doi.org/10.1101/360594

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Photosynthesis-derived carbohydrate supply sustains CuCl2-induced phytoalexin production in rice leaves

Phytoalexins are antimicrobial metabolites whose biosynthesis is triggered by signaling activated by both biotic and abiotic elicitors, but the physiological conditions that sustain their production remain poorly understood. Here, we examined how light and carbohydrate availability affect CuCl2-induced production of diterpenoid (phytocassanes and momilactones) and flavonoid (sakuranetin) phytoalexins in rice (Oryza sativa L.) leaf disks. Darkness strongly suppressed both the accumulation of all three phytoalexin groups and the induction of their biosynthetic genes. In darkness, endogenous sucrose, glucose, and fructose declined to 3%-8% of the levels in the light, whereas early accumulation of jasmonic acid and jasmonoyl-L-isoleucine (JA-Ile) was not detectably reduced. Exogenous sucrose restored phytoalexin accumulation in darkness in a dose-dependent manner, together with the expression of the suppressed biosynthetic genes, whereas equimolar mannitol had no effect. Glucose also restored sakuranetin accumulation in darkness but only partially restored diterpenoid accumulation, whereas the glucose analog 2-deoxy-D-glucose did not, and it suppressed CuCl2-induced accumulation in the light in a dose-dependent manner. In the light, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosynthetic electron transport, depleted soluble sugars and suppressed phytoalexin accumulation, and sucrose reversed this suppression. Sugars alone induced little phytoalexin accumulation, indicating that carbohydrates act permissively rather than as elicitors. Diterpenoid phytoalexins depended more strongly on light than sakuranetin, yet both classes depended on carbohydrate availability. These results indicate that photosynthesis-derived carbohydrate supply sustains elicitor-induced phytoalexin production in rice leaves and largely accounts for its light dependence.

plant biology↗

bioRxiv2026

Transcriptome analysis provides insights into candidate genetic regulators of birch response to salt stress

Abstract Background: Soil salinization is a worldwide matter of concern and can result in a series of agricultural and ecological problems. Previous transcriptome data have shown genetic regulatory mechanisms of salt stress response in a salt-tolerant species of Betula halophila and a salt-sensitive species of B. platyphylla, but comparative analysis of transcriptional changes in the the two species remains limited. Aims: We compared gene expression in leaves of B. halophila and leaves and roots of B. platyphylla. Methods: Differentially expressed genes (DEGs) were identified after 24 h of salt stress, followed by Gene Ontology enrichment and gene regulatory network (GRN) construction. Selected DEGs were examined by quantitative real-time PCR (RT-qPCR). Results: Compared with 0 h, 956 DEGs were found in B. halophila leaves (BHLeaf), 2,955 in B. platyphylla leaves (BPLeaf), and 3,827 in B. platyphylla roots (BPRoot). BHLeaf DEG expression patterns were similar to those of BPRoot. DEGs from BHLeaf and BPRoot were enriched in cell wall organization or biogenesis, whereas hormone biosynthesis and signaling genes were altered mainly in B. platyphylla. RT-qPCR showed that selected DEGs were induced by 200 mM NaCl for 24 h in B. platyphylla. Conclusions: Our work uncovered genetic mechanisms of salt stress response commonly and uniquely occurring in two birch species and provides resources for breeding salt-tolerant birch.

plant biology↗

bioRxiv2026

Minimal requirements and evolution of polar membrane targeting in the land plant SOSEKI protein family

Accurate spatial distribution of polar proteins is essential for cell function, but mechanisms underlying polar protein targeting in plants are poorly understood. Here, we dissect the molecular mechanisms underlying the polar targeting of the SOSEKI1 (SOK1) protein in Arabidopsis thaliana. Using extensive mutagenesis and truncation analyses of the polarity domain, we mapped the minimal polarity fragment necessary and sufficient for stable polar targeting to a 25-amino-acid region. This region likely forms an amphipathic helix, and mutations reveal that both its polar and apolar faces are essential for membrane association and polarity. Using phylogenetic analysis, we reconstruct the evolutionary history of the minimal polar targeting region across land plants. Using cross-species expression and protein localization, we infer the ancestral polar SOK localization pattern and show how it remained remarkably conserved, only to diversify upon gene duplication. This work identifies a polar targeting peptide in plants, reveals a mechanism for polar membrane targeting of a plant protein family, and demonstrates both conservation and diversification within this family.

plant biology↗