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Wild barley (Hordeum spontaneum) and barley landraces are important sources of genetic variation for disease resistance. Thirty wild barley (H. spontaneum) genotypes and 30 barley landraces were evaluated for susceptibility to two Drechslera graminea isolates. Virulence differences were observed between the isolates, while the responses of the host genotypes to the isolates also varied. Of the H. spontaneum genotypes, 23% and 63%, respectively, were resistant to the Yozgat D. graminea isolate, and Eskişehir D. graminea isolates.  On the other hand, 43% and 90% of the barley landraces were resistant to Yozgat and Eskişehir D. graminea isolates, respectively. Hordeum spontaneum genotypes 13, 24, 27, 29, 54, 86, and 91 exhibited resistance to both D. graminea isolates, while genotypes 14 and 32 showed intermediate reactions to the Yozgat isolate and resistant reactions to the Eskişehir isolate. Barley landraces 21, 37, 38, 39, 40, 73, 98, 128, 139, 153, 159,167, and 171 showed resistant reactions, and barley landrace 8 showed an intermediate reaction to both isolates. Barley landraces 3, 20, 24, 71, 101, 103, 104 and 160 exhibited intermediate responses to the Yozgat isolate and a resistant response to the Eskişehir isolate. Using resistant barley genotypes would reduce the need for pesticides for control of leaf stripe, and be an environmentally preferred strategy for disease control. The disease resistance present in wild barley and barley landraces are important for expanding the genetic basis of cultivated barley (H. vulgare). The resistant and intermediate genotypes identified in this study could be used as resistance sources in barley breeding, or landraces could be used directly for commercial barley production.

Barley leaf stripe, caused by Pyrenophora graminea, significantly reduces yield. Polygalacturonase, a key fungal pectinase, facilitates cell wall degradation for nutrition acquisition and colonization. To determine whether P. graminea contains polygalacturonase (PgPG)-encoding genes and their role in pathogenicity, four PgPG genes (PgPG1–PgPG4) were identified in the P. graminea genome. Quantitative RT-PCR revealed that PgPG1 had the highest inducible expression during barley infection, suggesting its critical vital role in pathogenesis. PgPG1 was silenced and overexpressed in P. graminea QWC (wild-type) using CaCl2-PEG4000-mediated protoplast transformation. The PgPG1 RNAi mutants exhibited slower growth, while overexpression mutants grew faster. Relative to the wild-type, the disease incidence of Alexis, a highly susceptible barley variety, decreased by 62.94%, 42.19%, 45.74%, and 40.67% for RNAi mutants, and increased by 12.73%, 12.10%, 12.63%, and 10.31% for overexpression mutants. Pathogenicity analysis showed decreased disease incidence with PgPG1 RNAi mutants and increased severity with overexpression mutants. Trypan blue staining and polygalacturonase activity assays confirmed that overexpression mutants caused more severe damage compared to wild-type and RNAi mutants. These findings indicate that PgPG1 plays a vital role in the pathogenicity of P. graminea in barley and has great potential as a pathogen target gene to develop a durable resistance variety to P. graminea.

Wild barley (Hordeum spontaneum) and barley landraces are important sources of genetic variation for disease resistance. Thirty wild barley (H. spontaneum) genotypes and 30 barley landraces were evaluated for susceptibility to two Drechslera graminea isolates. Virulence differences were observed between the isolates, while the responses of the host genotypes to the isolates also varied. Of the H. spontaneum genotypes, 23% and 63%, respectively, were resistant to the Yozgat D. graminea isolate, and Eskişehir D. graminea isolates. On the other hand, 43% and 90% of the barley landraces were resistant to Yozgat and Eskişehir D. graminea isolates, respectively. Hordeum spontaneum genotypes 13, 24, 27, 29, 54, 86, and 91 exhibited resistance to both D. graminea isolates, while genotypes 14 and 32 showed intermediate reactions to the Yozgat isolate and resistant reactions to the Eskişehir isolate. Barley landraces 21, 37, 38, 39, 40, 73, 98, 128, 139, 153, 159,167, and 171 showed resistant reactions, and barley landrace 8 showed an intermediate reaction to both isolates. Barley landraces 3, 20, 24, 71, 101, 103, 104 and 160 exhibited intermediate responses to the Yozgat isolate and a resistant response to the Eskişehir isolate. Using resistant barley genotypes would reduce the need for pesticides for control of leaf stripe, and be an environmentally preferred strategy for disease control. The disease resistance present in wild barley and barley landraces are important for expanding the genetic basis of cultivated barley (H. vulgare). The resistant and intermediate genotypes identified in this study could be used as resistance sources in barley breeding, or landraces could be used directly for commercial barley production.

Background Barley leaf stripe, caused by Pyrenophora graminea , is a seed-borne fungal disease that significantly impacts the production of hulless barley ( Hordeum vulgare var. nudum ) on the Qinghai‒Tibet Plateau. In this study, we conducted an indoor disease resistance screen of 28 hulless barley germplasm resources using the highly pathogenic P. graminea strains L-7 and FS-18 and identified resistant (ZYM2179) and susceptible (Chaiqing No. 1) materials. We then inoculated these two resources with the highly pathogenic P. graminea strain L-7 and performed morphological observation of sections stained with WGA-AF488 and RNA-seq at different time points. Results As the duration of infection increased, the degree of P. graminea invasion and the number of hyphae significantly increased. In addition, the incidence rate of P. graminea infection in the susceptible resource was greater than that in the resistant resource. A total of 18,523 differentially expressed genes were identified in the transcriptome analysis, functional annotation revealed significant enrichment of transcription factor families such as B3 (539), ERF (294), and NAC (150). Trend analysis identified 20 distinct expression profiles, with differences in gene expression patterns between the two resources. The differentially expressed genes were dynamically regulated over time, with the susceptible resource showing an increasing trend in gene expression, while the resistant resource exhibited an initial increase followed by a decrease. With significant differences in the number of differentially expressed genes enriched in different GO and KEGG pathways between the resistant and susceptible resources. One hundred and four differentially expressed genes were identified in the resistant resource, and these genes were enriched mainly in pathways such as metabolism and plant–pathogen interactions. It is noteworthy that the Rboh and RbohD genes, which are involved in reactive oxygen species production and plant-pathogen interactions, were upregulated in the resistant variety. Conclusions The relative expression levels of the 10 candidate genes validated by RT-qPCR, such as HSP70-4 and PER1 , were Significantly different between resistant and susceptible resources at 12 h post-inoculation. This is consistent with the results of morphological and transcriptome analysis, indicating that these genes are likely related to barley leaf stripe resistance. This study provides a theoretical basis for the discovery of barley leaf stripe resistance genes and the study of resistance mechanisms in hulless barley and is important for the breeding of new disease-resistant varieties and the development of the hulless barley industry.

Barley leaf stripe, a disease mainly caused by Pyrenophora graminea ( P. graminea ) infection, severely affects barley yield and quality and is one of the most widespread diseases in barley production. However, little is known about the underlying molecular mechanisms of leaf stripe resistance. In this study, the transcript expression profiles of normal and infected leaves of resistant Tibetan hulless barley ( Hordeum vulgare L. var. nudum Hook. f.) variety Kunlun 14 and susceptible variety Z1141 were analyzed by RNA sequencing (RNA-seq). The results showed a total of 7,669 and 5,943 differentially expressed genes (DEGs) were found in resistant and susceptible Kunlun 14 and Z1141, respectively, with 8,916 DEGs found between Kunlun 14 and Z1141. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the 8,916 DEGs identified many significantly enriched categories and pathways, of which a plant–pathogen interaction pathway, containing a total of 102 genes (100 known genes and two novel genes), was found, that was very important for the study of the leaf stripe resistance mechanism. Using RNA-seq, small RNA sequencing (miRNA-seq) combined with degradome sequencing (degradome-seq), four pairs associated with leaf-stripe miRNAs and target genes were obtained, namely Hvu-miR168-5p and Argonaute1 ( HvAGO1 ), Hvu-novel-52 and growth-regulating factor 6 ( HvGRF6 ), Hvu-miR6195 and chemocyanin-like protein ( CLP ), and Hvu-miR159b and gibberellin - dependent MYB ( GAMYB ). Transformation of the important target gene HvAGO1 into Arabidopsis verified that HvAGO1 could against Botrytis cinerea . Then RNA-seq and miRNA-seq of Arabidopsis transformed with overexpressed of HvAGO1 were performed. Based on the above research results, we constructed a Protein-Protein Interaction (PPI) network of barley leaf stripe resistance. This study lays the foundation for the study of the barley leaf stripe resistance mechanism and provides new targets for the genetic improvement of disease-resistant barley varieties.

The Californian Channel Islands are near-shore islands with high levels of endemism, but extensive habitat loss has contributed to the decline or extinction of several endemic taxa. A key parameter for understanding patterns of endemism and demography in island populations is the magnitude of inter-island dispersal. This paper estimates the extent of migration and genetic differentiation in three extant and two extinct populations of Channel Island song sparrows (Melospiza melodia graminea). Inter-island differentiation was substantial (G''ST: 0.14-0.37), with San Miguel Island having the highest genetic divergence and lowest migration rates. Santa Rosa and Santa Cruz Island populations were less diverged with higher migration rates. Genetic signals of past population declines were detected in all of the extant populations. The Channel Island populations were significantly diverged from mainland populations of M. m. heermanni (G''ST: 0.30-0.64). Ten mtDNA haplotypes were recovered across the extant and extinct Channel Island population samples. Two of the ten haplotypes were shared between the Northern and Southern Channel Islands, with one of these haplotypes being detected on the Californian mainland. Our results suggest that there is little contemporary migration between islands, consistent with early explanations of avian biogeography in the Channel Islands, and that song sparrow populations on the northern Channel Islands are demographically independent.

Leaf stripe disease on barley (Hordeum vulgare) is caused by the seed-transmitted hemi-biotrophic fungus Pyrenophora graminea. Race-specific resistance to leaf stripe is controlled by two known Rdg (Resistance to Drechslera graminea) genes: the H. spontaneum-derived Rdg1a and Rdg2a, identified in H. vulgare. The aim of the present work was to isolate the Rdg2a leaf stripe resistance gene, to characterize the Rdg2a locus organization and evolution and to elucidate the histological bases of Rdg2a-based leaf stripe resistance. We describe here the positional cloning and functional characterization of the leaf stripe resistance gene Rdg2a. At the Rdg2a locus, three sequence-related coiled-coil, nucleotide-binding site, and leucine-rich repeat (CC-NB-LRR) encoding genes were identified. Sequence comparisons suggested that paralogs of this resistance locus evolved through recent gene duplication, and were subjected to frequent sequence exchange. Transformation of the leaf stripe susceptible cv. Golden Promise with two Rdg2a-candidates under the control of their native 5' regulatory sequences identified a member of the CC-NB-LRR gene family that conferred resistance against the Dg2 leaf stripe isolate, against which the Rdg2a-gene is effective. Histological analysis demonstrated that Rdg2a-mediated leaf stripe resistance involves autofluorescing cells and prevents pathogen colonization in the embryos without any detectable hypersensitive cell death response, supporting a cell wall reinforcement-based resistance mechanism. This work reports about the cloning of a resistance gene effective against a seed borne disease. We observed that Rdg2a was subjected to diversifying selection which is consistent with a model in which the R gene co-evolves with a pathogen effector(s) gene. We propose that inducible responses giving rise to physical and chemical barriers to infection in the cell walls and intercellular spaces of the barley embryo tissues represent mechanisms by which the CC-NB-LRR-encoding Rdg2a gene mediates resistance to leaf stripe in the absence of hypersensitive cell death.

Composition and diversity in gut microbiota are impacted by a wide variety of factors. The similarity of gut microbiota in related or sympatric species has been gaining recent traction. Here, 16S rRNA gene sequencing technology was employed to study the gut microbiota of three sympatric frog species, namely Odorrana tormota, O. graminea, and Amolops wuyiensis. In these three frog species, the most abundant phylum was Proteobacteria, followed by Bacteroidetes, Verrucomicrobia, and Firmicutes. The most abundant family was Burkholderiaceae in three species. The most dominant genera were Burkholderia, Caballeronia, and Paraburkholderia with the highest relative abundance in O. tormota, O. graminea, and A. wuyiensis, respectively. No differences were observed in alpha diversity indexes among the three frog species. However, bacterial similarity of gut microbiota was significantly different between O. tormota and A. wuyiensis and between O. graminea and A. wuyiensis. Metabolism‐related gene function was predominantly enriched in the gut microbiota of the three evaluated frog species. From these findings, that the relative abundance of the gut microbiota and predicted gene functions differed in three species, we conclude that there were significant differences in the gut microbiota of the three species. Similar alpha diversity and interspecific bacterial similarity in the gut might be related to bacterial transmission among the three Anura frogs evaluated in this study. These three Anura frogs are commonly observed on rocks near streams. These species are distributed along mountain streams and congregate in large numbers during the breeding reason in mountain streams. This will provide a good model for the study on the gut microbial differences in sympatric frogs.

The phytochemical screening of potentially efficient medicinal herbs is one of the current focus areas of modern pharmacochemistry. This work aims to analyze the phytochemical composition of the aboveground parts in three Stellaria species (S. bungeana, S. graminea, S. holostea). The study was conducted between May and July 2020 in the Moscow region of the Russian Federation. Yield values for raw herbal materials and density of stitchwort samples per 1 m2 (154 sites in total) were recorded, followed by a phytochemical analysis of the dry mass by chromatography. The maximum yield of S. bungeana was established to be 1.5 times higher than in two other species (p ≤ 0.05). In S. graminea, the maximum pectin concentration was 12 times higher than in S. holostea (p ≤ 0.001) and 0.5 times higher than in S. bungeana (p ≤ 0.05). The number of polysaccharides in S. bungeana was 14 times higher than in S. graminea (p ≤ 0.001) and two higher than in S. holostea (p ≤ 0.05). Hemicellulose content of S. bungeana extract was twice as high as that of other species (p ≤ 0.05). Tannins in S. graminea were found two times more often than in S. holostea (p ≤ 0.05) and eight times more often in S. bungeana (p ≤ 0.01). Vitamin C content in S. graminea was two times greater than in the other two stitchwort species (p ≤ 0.05). Stitchwort is a common, widespread plant that makes it easy to collect without harming plant communities. Biologically active substances (polysaccharides, vitamin C, tannins, and pectins) were found in the composition of all stitchwort species with a preventive and therapeutic effect on the human body. The concentration of tannins and vitamin C is maximal in S. graminea extract, amounting to 2.6% and 45.9%, accordingly. The extract from S. bungeana contains a lot of hemicellulose (13.2%) and polysaccharides (7.2%). No high concentration of these substances was recorded in S. holostea, which makes this species the least pharmaceutically valuable. S. graminea and S. bungeana plants can be recommended for pharmaceutical processing due to the high concentrations of vitamin C, pectins, tannins, polysaccharides, and hemicellulose.

Halophytic plants growing in harsh desert environments are rich reservoirs of unique endophytic microorganisms. Here, healthy fresh plants of the families Tamaricaceae and Amarantaceae at three saline locations in Iran were investigated for their bioactive endophytic fungi. Among a vast number of isolates, eight isolates were identified as Humicola fuscoatra (Sordariomycetes, Pezizomycotina, Ascomycota) by microscopy and representative DNA sequences of the 5.8S rDNA (ITS) and partial β-tubulin (TUB2). Those isolates were halotolerant, and highly bioactive, so that their intra- and extra-cellular metabolites possessed in vitro antifungal, antibacterial and antiproliferative activities, against a number of fungal and bacterial plant pathogens including the fungi Arthrobotrys conoides, Pyrenophora graminea, Pyricularia grisea and the bacteria Agrobacterium tumefaciens, Pseudomonas syringae and Xanthomonas oryzae. Chemical analyses of metabolites from the endophytes using HNMR, CNMR, NOESY, COSY, HMBC, HSQC, DEPT, TOCSY and EI MASS techniques identified 3,8-dihydroxy-1-methyl-9,10-anthracenedione (aloesaponarin II; an anthraquinone derivative), 1,8,9-anthracenetriol structure (chrysarobin; an anthranol derivative) and 2,4-di-tert-butylthiophenol in fungal extracts. To the best of our knowledge, this is the first report of endophytic association of halotolerant H. fuscoatra isolates with Tamaricaceae and Amarantaceae, and their bioactivity against plant pathogens. Also, the capability of chrysarobin and aloesaponarin II production is new to the fungal kingdom. These findings may find application in agriculture, pharmacology, and biotechnology.