Description of Clavibacter zhangzhiyongii sp. nov., a phytopathogenic actinobacterium isolated from barley seeds, causing leaf brown spot and decline.
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ABSTRACT:
SUBMITTER: Tian Q
PROVIDER: S-EPMC8289203 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:In recent years, a new root rot disease in barley, which is caused by an Aphanomyces species, was found in field surveys in Southern Sweden and Denmark. Its symptoms occurred at the early tillering stage, around the BBCH 21 growth stage, and included the yellowing of leaves, brown coleoptiles, and the discolouration of roots. Prolonged soil wetness after rainfall favoured disease development, which sometimes advanced the yellowing patches to entire fields, resulting in lower yields. Oospores were found in the fine roots of diseased plants, and Aphanomyces isolates were obtained from these roots, as well as from the roots of barley plants grown in the greenhouse in soil samples from infected fields. Based on morphological analysis, we found that the new isolates were similar to those already obtained from barley and spinach roots in the 1990s in the same growing area. The morphological and molecular analyses performed in this study clearly separated and distinguished these barley isolates from other known Aphanomyces, and hereby Aphanomyces macrosporus sp. nov. is proposed as a new plant pathogenic species. It has larger oogonia and oospores than A. euteiches, A. cochlioides, and A. cladogamus, with one up to eight diclinous antheridia per oogonium. The phylogenetic analysis of the ITS rDNA region sequences grouped these new Aphanomyces isolates in a monophyletic clade, which was clearly distinguished from other plant pathogenic Aphanomyces species. The further pathogenicity of A. macrosporus on other plants is currently under investigation, but it is clear that it can at least infect barley, spinach, and sugar beet, indicating a wide host range for this species. The widespread presence and presumably broad host range of this new pathogenic Aphanomyces species must be considered in crop rotations.
| S-EPMC10744466 | biostudies-literature
Project description:The genus Alternaria is a group of infectious/contagious pathogenic fungi that not only invade a wide range of crops but also induce severe allergic reactions in a part of the human population. In this study, two strains Alternaria longipes cx1 and Alternaria alternata cx2 were isolated from different brown spot lesions on infected tobacco leaves. Their complete genomes were sequenced, de novo assembled, and comparatively analyzed. Phylogenetic analysis revealed that A. longipes cx1 and A. alternata cx2 diverged 3.3 million years ago, indicating a recent event of speciation. Seventeen non-ribosomal peptide synthetase (NRPS) genes and 13 polyketide synthase (PKS) genes in A. longipes cx1 and 13 NRPS genes and 12 PKS genes in A. alternata cx2 were identified in these two strains. Some of these genes were predicted to participate in the synthesis of non-host specific toxins (non-HSTs), such as tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME). By comparative genome analysis, we uncovered that A. longipes cx1 had more genes putatively involved in pathogen-plant interaction, more carbohydrate-degrading enzymes and more secreted proteins than A. alternata cx2. In summary, our results demonstrate the genomic distinction between A. longipes cx1 and A. altenata cx2. They will not only improve the understanding of the phylogenetic relationship among genus Alternaria, but more importantly provide valuable genomic resources for the investigation of plant-pathogen interaction.
| S-EPMC4861331 | biostudies-literature
Project description:Lasiodiplodia (family Botryosphaeriaceae) is a widely distributed fungal genus that causes a variety of diseases in tropical and subtropical regions. During 2020−2021, a routine survey of fruit tree plants was conducted in five Egyptian Governorates, and fresh samples exhibiting dieback, decline, leaf spot and root rot symptoms were collected. Collection from eight different symptomatic leaves, twigs, branches and roots of fruit trees yielded 18 Lasiodiplodia-like isolates. The sequencing data from the internal transcribed spacer region (ITS), partial translation elongation factor 1-alpha (tef1-a) and β-tubulin (tub2) were used to infer phylogenetic relationships with known Lasiodiplodia species. Two isolates obtained from black necrotic lesions on Phoenix dactylifera leaves were identified as a putative novel species, L. newvalleyensis sp. nov., and were thus subjected to further morphological characterization. The results of isolation and molecular characterization revealed that L. theobromae (n = 9) was the most common species on Mangifera indica, Citrus reticulata, C. sinensis, Ficus carica, Prunus persica, Prunus armeniaca and Pyrus communis trees. Lasiodiplodia pseudotheobromae (n = 5) was isolated from M. indica, Prunus persica and C. sinensis. Lasiodiplodia laeliocattleyae (n = 2) was isolated from C. reticulata. Pathogenicity test results suggested that all Lasiodiplodia species were pathogenic to their hosts. The present study is considered the first to characterize and decipher the diversity of Lasiodiplodia species associated with fruit trees in Egypt, using the multi-locus ITS, tef1-a and tub2 sequence data, along with morphological and pathogenic trials. To our knowledge, this is the first report of L. newvalleyensis on Phoenix dactylifera and L. laeliocattleya on C. reticulata in Egypt and worldwide.
| S-EPMC9694705 | biostudies-literature
Project description:High temperatures and the seasonality in tropical ecosystems favours plant pathogens, which result in many fungal diseases. Among these, diseases caused by Botryosphaeriaceae species are prominent as dieback, canker and leaf spots. In this research, we isolated one leaf-spot-causing Botryosphaeriaceae species from Ficus altissima leaves, which were collected in Guangzhou, Guangdong Province, China. Isolation and identification of the pathogen were based on morphological and molecular aspects. Based on multigene phylogenetic analysis of combined internal transcribed spacer (ITS), translation elongation factor 1-α gene (tef1) and beta-tubulin gene (tub2), the fungus associated with leaf spots on F. altissima is described as Lasiodiplodia fici, a novel species. Pathogenicity assays were conducted by inoculating the fungus onto detached shoots and plants under controlled environmental conditions. The results revealed that the L. fici isolates can infect the plant tissues under stress conditions by developing disease symptoms on detached shoots within three days. However, when it was inoculated onto the leaves of the host and grown in natural conditions, the progression of the disease was slow. The putative pathogen was re-isolated, and Koch's assumptions were satisfied. This is the first report of Lasiodiplodia species causing disease on Ficus altissima. Results from the present study will provide additional knowledge on fungal pathogens associated with forest and ornamental plant species.
| S-EPMC9412989 | biostudies-literature
Project description:Brown spot of citrus caused by Alternaria citri is one of the emerging threats to the successful production of citrus crops. The present study, conducted with a substantial sample size of 50 leaf samples for statistical reliability, aimed to determine the change in mineral content in citrus leaves after brown spot disease attack. Leaf samples from a diverse range of susceptible citrus varieties (Valentia late, Washington navel, and Kinnow) and resistant varieties (Citron, Eruka lemon, and Mayer lemon) were analyzed. Significant variations (p ≤ 0.05) in mineral contents were observed across reaction groups (inoculated and un-inoculated), types (resistant and susceptible), and varieties of citrus in response to infection of Alternaria citri. The analysis of variance showed significant changes in mineral levels of citrus leaves, including nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), sodium (Na), iron (Fe), and copper (Cu). The results indicate that the concentration of N and P differed by 6.63% and 1.44%, respectively, in resistant plants, while susceptible plants showed a difference of 6.07% and 1.19%. Moreover, resistant plants showed a higher concentrations of K, Ca, Mg, Zn, Na, Fe, and Cu at 8.40, 2.1, 1.83, 2.21, 1.58, 2.89, and 0.36 ppm respectively, compared to susceptible plants which showed concentrations of 5.99, 1.93, 1.47, 1.09, 1.24, 1.81, and 0.31 ppm respectively. Amounts of mineral contents were reduced in both resistant as well as susceptible plants of citrus after inoculation. Amount of N (8.56), P (1.87) % while K (10.74), Ca (2.71), Mg (2.62), Zn (2.20), Na (2.08), Fe (3.57) and Cu (0.20) ppm were recorded in un-inoculated group of citrus plants that reduced to 3.15 and 0.76% and 3.66, 1.40, 0.63,0.42, 0.74, 1.13 and 0.13 ppm in inoculated group respectively. It was accomplished that susceptible varieties contained lower ionic contents than resistant varieties. The higher concentrations of ionic contents in resistant citrus varieties build up the biochemical and physiological processes of the citrus plant, which help to restrict spread of pathogens. Further research could explore the interplay between mineral nutrition and disease resistance in citrus, potentially leading to the development of new disease-resistant varieties.
| S-EPMC11221669 | biostudies-literature
Project description:BackgroundBabesiosis is a tick-borne infection caused by piroplasmid protozoa and associated with anemia and severe disease in humans, domestic animals and wildlife. Domestic cats are infected by at least six Babesia spp. that cause clinical disease.MethodsInfection with a piroplasmid species was detected by microscopy of stained blood smears in three sick cats from Israel. Genetic characterization of the piroplasmid was performed by PCR amplification of the 18S rRNA, cytochorme B (CytB) and heat shock protein 70 (HSP70) genes and the internal transcribed spacer (ITS) locus, DNA sequencing and phylogenetic analysis. In addition, Haemaphysalis adleri ticks collected from two cats were analyzed by PCR for piroplasmids.ResultsThe infected cats presented with anemia and thrombocytopenia (3/3), fever (2/3) and icterus (1/3). Comparison of gene and loci sequences found 99-100% identity between sequences amplified from different cats and ticks. Constructed phylogenetic trees and DNA sequence comparisons demonstrated a previously undescribed Babesia sp. belonging to the Babesia sensu stricto (clade X). The piroplasm forms detected included pear-shaped merozoite and round-to-oval trophozoite stages with average sizes larger than those of Babesia felis, B. leo and B. lengau and smaller than canine Babesia s.s. spp. Four of 11 H. adleri adult ticks analyzed from cat # 3 were PCR positive for Babesia sp. with a DNA sequence identical to that found in the cats. Of these, two ticks were PCR positive in their salivary glands, suggesting that the parasite reached these glands and could possibly be transmitted by H. adleri.ConclusionsThis study describes genetic and morphological findings of a new Babesia sp. which we propose to name Babesia galileei sp. nov. after the Galilee region in northern Israel where two of the infected cats originated from. The salivary gland PCR suggests that this Babesia sp. may be transmitted by H. adleri. However, incriminating this tick sp. as the vector of B. galilee sp. nov. would require further studies.
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Project description:During disease surveys of Angelica acutiloba plants in Korea, leaf spot symptoms were observed in a field in Andong in July 2019, and stem rot symptoms in vinyl greenhouses in Yangpyeong in April 2020. Incidence of leaf spot and stem rot of the plants ranged from 10 to 20% and 5 to 30%, respectively. Morphological and cultural characteristics of fungal isolates from the leaf spot and stem rot symptoms fitted into those of the genus Phoma. Molecular phylogenetic analyses of two single-spore isolates from the symptoms using concatenated sequences of LSU, ITS, TUB2, and RPB2 genes authenticated an independent cluster from other Didymella (anamorph: Phoma) species. Moreover, the isolates showed different morphological and cultural characteristics in comparison to closely related Didymella species. These discoveries confirmed the novelty of the isolates. Pathogenicity of the novel Didymella species isolates was substantiated on leaves and stems of A. acutiloba through artificial inoculation. Thus, this study reveals that Didymella acutilobae sp. nov. causes leaf spot and stem rot in Angelica acutiloba.
| S-EPMC10621254 | biostudies-literature
Project description:A haloalkaliphilic hydrolytic actinobacterium, strain ACPA22T, was enriched and isolated in pure culture from saline alkaline soil (soda solonchak) in northeastern Mongolia. The isolate was facultatively alkaliphilic, growing at pH 6.5-10.5 (optimum at 7.3-9.0) and highly salt-tolerant, tolerating up to 3 M total Na+ as carbonates. The hydrolytic nature of ACPA22T was confirmed by two different growth-dependent methods and by the presence of multiple glycosidase-encoding genes in the genome. The 16S rRNA gene-based phylogenetic analysis demonstrated that strain ACPA22T formed a deep-branching lineage within the family Glycomycetaceae, with the highest sequence similarity value to Glycomyces buryatensis 18T (92.1 %) and Salininema proteolyticum Miq-4T (91.8 %). The average amino acid identity values (56.1-61.5 %) between ACPA22T and other Glycomycetaceae members with available genomes did not exceed the threshold reported for different genera. The cell wall of ACPA22T contained meso-diaminopimelic acid, glycine, glutamic acid and alanine in a molar ratio, characteristic of the peptidoglycan type A1γ'. The whole-cell sugars included mannose, galactose, arabinose, ribose and xylose. The major menaquinones were MK-10(Н4) and MK-11(Н4). The identified polar lipids were represented by phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. In addition, the strain had a few unidentified characteristic polar lipids, including an amine-containing phospholipid with chromatographic mobility similar to that of phosphatidylinositol. The polar lipid fatty acids were dominated by anteiso-C17 : 0 and iso-C16 : 0. The genome included a chromosome of 3.94 Mbp (G+C content 61.5 mol%) encoding 3285 proteins and two plasmids of 59.8 and 14.8 kBp. Based on the data obtained in this study, a new genus and species, Natronoglycomyces albus gen. nov., sp. nov, is proposed with the type strain ACPA22T (=DSM 106290T=VKM Ac-2771T).
| S-EPMC8289206 | biostudies-literature
Project description:Cochliobolus miyabeanus is known as a significant causal agent in relation to brown spot disease of rice and causes significant yield losses. In the present study, the complete mitochondrial genome was determined using next-generation sequencing technology. This complete mitogenome is a circular molecule of 124,887 bp in length. It contains 13 conserved protein-coding genes, 21 transfer RNA genes, 2 ribosomal RNA genes and 9 open reading frames. The overall base composition of C. miyabeanus is 35.4% A, 34.4% T, 14.4% C, 15.8% G, with a CG content of 30.2%. Phylogenetic analysis based on concatenated protein genes from 15 taxa within Pezizomycotina showed that C. miyabeanus is closely related to Bipolaris cookei in the family Pleosporaceae (Dothideomycetes, Pleosporales). This work would facilitate the understanding of systematics and evolutionary biology of phytopathogenic fungi.
| S-EPMC7706553 | biostudies-literature
Project description:Bipolaris sorokiniana is a fungal pathogen that infects wheat, barley, and other crops, causing spot blotch disease. The disease is most common in humid, warm, wheat-growing regions, with South Asia's Eastern Gangetic Plains serving as a hotspot. There is very little information known about its genetic variability, demography, and divergence period. The current work is the first to study the phylogeographic patterns of B. sorokiniana isolates obtained from various wheat and barley-growing regions throughout the world, with the goal of elucidating the demographic history and estimating divergence times. In this study, 162 ITS sequences, 18 GAPDH sequences, and 74 TEF-1α sequences from B. sorokiniana obtained from the GenBank, including 21 ITS sequences produced in this study, were used to analyse the phylogeographic pattern of distribution and evolution of B. sorokiniana infecting wheat and barley. The degrees of differentiation among B. sorokiniana sequences from eighteen countries imply the presence of a broad and geographically undifferentiated global population. The study provided forty haplotypes. The H_1 haplotype was identified to be the ancestral haplotype, followed by H_29 and H_27, with H_1 occupying a central position in the median-joining network and being shared by several populations from different continents. The phylogeographic patterns of species based on multi-gene analysis, as well as the predominance of a single haplotype, suggested that human-mediated dispersal may have played a significant role in shaping this pathogen's population. According to divergence time analysis, haplogroups began at the Plio/Pleistocene boundary.
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