scholarly journals Characterization and Functional Importance of Two Glycoside Hydrolase Family 16 Genes from the Rice White Tip Nematode Aphelenchoides besseyi

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 374
Author(s):  
Hui Feng ◽  
Dongmei Zhou ◽  
Paul Daly ◽  
Xiaoyu Wang ◽  
Lihui Wei

The glycoside hydrolase family 16 (GH16) is widely found in prokaryotes and eukaryotes, and hydrolyzes the β-1,3(4)-linkages in polysaccharides. Notably, the rice white tip nematode Aphelenchoides besseyi harbors a higher number of GH16s compared with other plant-parasitic nematodes. In this work, two GH16 genes, namely AbGH16-1 and AbGH16-2, were isolated and characterized from A. besseyi. The deduced amino acid sequences of AbGH16-1 and AbGH16-2 contained an N-terminal signal peptide and a fungal Lam16A glucanase domain. Phylogenetic analysis revealed that AbGH16-1 and AbGH16-2 clustered with ascomycete GH16s, suggesting AbGH16-1 and AbGH16-2 were acquired by horizontal gene transfer from fungi. In situ hybridization showed that both AbGH16-1 and AbGH16-2 were specifically expressed in the nematode gonads, correlating with qPCR analysis that showed the high transcript levels of the two genes in the female nematodes. AbGH16-1 and AbGH16-2 were also significantly induced in nematodes feeding on Botrytis cinerea. Characterization of the recombinant protein showed AbGH16-1 and AbGH16-2 displayed pronounced inhibition of both conidial germination and germ tube elongation of B. cinerea. In addition, silencing of AbGH16-1 and AbGH16-2 by RNA interference significantly decreased the reproduction ability of A. besseyi and had a profound impact on the development process of offspring in this nematode. These findings have firstly proved that GH16s may play important roles in A.besseyi feeding and reproduction on fungi, which thus provides novel insights into the function of GH16s in plant-parasitic nematodes.

EDIS ◽  
2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Lindsay Wheeler ◽  
William Talmadge Crow

There are nematodes of several genera that feed on plant stems and foliage, including Aphelenchoides, Bursaphelenchus, Anguina, Ditylenchus and Litylenchus. Herein, we apply the common name “foliar nematode” specifically to plant-feeding nematodes in the genus Aphelechoides, specifically Aphelenchoides besseyi, Aphelenchoides fragariae, and Aphelenchoides ritzemabosi. While most members of Aphelenchoides are fungivorous (feed on fungi), these three species have populations that are facultative plant-parasites that can feed on live plant tissue. Ten other species of Aphelenchoides also are recognized as facultative plant-parasites, but these are not as commonly encountered or as economically significant as the aforementioned species. Unlike most plant-parasitic nematodes, foliar nematodes can infest the aerial portions of plants rather than dwelling strictly in soil and plant roots. Damage from their feeding can reduce yield in food crops and ruin the appearance of ornamentals.https://edis.ifas.ufl.edu/in1279


2019 ◽  
Vol 74 (3-4) ◽  
pp. 85-89 ◽  
Author(s):  
Jan Muschiol ◽  
Anne S. Meyer

Abstract The ability of an engineered β-N-acetylhexosaminidase to utilize a reactive oxazoline as donor molecule for transglycosylation reaction to synthesize human milk oligosaccharide backbone structures was studied. The human milk oligosaccharide precursor lacto-N-triose II and three regioisomers could be synthesized using the oxazoline, which was either in situ-generated resulting in a chemo-enzymatic sequential cascade or was used as a purified compound. The highest observed concentration of overall transglycosylation products in a cascade reaction was 13.7 mM after 18.5 h, whereas the use of purified oxazoline resulted in 25.0 mM of transglycosylation products after 6.5 h. Remarkably, the in situ-generated oxazoline could be used without any further purification and it was shown that the used enzyme tolerated significant amounts of reagents such as triethylamine, which is reported for the first time for an enzyme from the glycoside hydrolase family 20.


Parasitology ◽  
1996 ◽  
Vol 113 (6) ◽  
pp. 589-597 ◽  
Author(s):  
R. H. C. Curtis

SUMMARYSecretions of plant-parasitic nematodes which are released into plant tissue may play critical roles in plant-nematode interactions. The identification and characterization of these molecules are of fundamental importance and may help to facilitate the development of novel strategies to interfere with nematode infection of plants and thereby decrease nematode-induced damage to crops. An antibody-based approach was used to isolate molecules present on the nematode surface and in nematode secretions. Monoclonal antibodies (MAbs) were produced to secretions and to whole Heterodera avenue 2nd-stage juveniles; several of these MAbs recognized molecules present in nematode secretions produced in vitro. Three of these molecules have been partly characterized in H. avenae, Globodera rostochiensis, G. pallida and Meloidogyne incognita. A MAb reacting with the surfaces of these nematodes recognized antigens of different molecular weight in each of the species tested. This difference in antigenicity might be related to specific functions in these nematodes. Preliminary results show that this antibody also localized the antigen in root cells surrounding the feeding site induced by M. incognita in Arabidopsis thaliana.


2021 ◽  
Author(s):  
Jung-Kai Hsu ◽  
Chia-Wei Weng ◽  
Jeremy J.W. Chen ◽  
Peichen J. Chen

Abstract Aphelenchoides besseyi could cause great yield loss on rice and many economically important crops. Acetylcholinesterase inhibitors were commonly used to mitigate plant parasitic nematodes. However, increasing nematicide-resistance has been reported due to the extensive use of these chemicals. The correlation between the AChE-inhibitor (fenamiphos) sensitivities and acetylcholinesterase (ace) genes in two isolates of A. besseyi (designated Rl and HSF) was established. The LD50 of fenamiphos to Rl and HSF were 572.2 ppm and 129.4 ppm, respectively, indicating that two nematode isolates had different sensitivities to fenamiphos. Three ace genes were cloned and sequenced in A. besseyi, and their homology was supported by phylogenic analysis with AChEs protein sequences from various vertebrate and invertebrate species. Molecular docking showed that the affinities of each AChEs to fenamiphos were higher in HSF isolate, indicating that there should be point mutations in Rl isolate AChEs. Treating the two isolates with 100 ppm fenamiphos for 12 h, three ace genes of HSF isolate were down-regulated but were up-regulated in Rl isolate. The results suggest that fenamiphos can transcriptionally modulate the expression of ace genes, as well as the variants in AChEs and increased expression of ace genes might be associated with fenamiphos-insensitivity in Rl isolate.


2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Bu-Yong Wang ◽  
Rong-Rong Wen ◽  
Ling Ma

Abstract, the nematode agent of rice tip white disease, causes huge economic losses in almost all the rice-growing regions of the world. Glutathione peroxidase (GPx), an esophageal glands secretion protein, plays important roles in the parasitism, immune evasion, reproduction and pathogenesis of many plant-parasitic nematodes (PPNs). Therefore, GPx is a promising target for control


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Laura E. Zeugner ◽  
Karen Krüger ◽  
Jimena Barrero-Canosa ◽  
Rudolf I. Amann ◽  
Bernhard M. Fuchs

AbstractGene clusters rich in carbohydrate-active enzymes within Flavobacteriia genera provide a competitiveness for their hosts to degrade diatom-derived polysaccharides. One such widely distributed polysaccharide is glucuronomannan, a main cell wall component of diatoms. A conserved gene cluster putatively degrading glucuronomannan was found previously among various flavobacterial taxa in marine metagenomes. Here, we aimed to visualize two glycoside hydrolase family 92 genes coding for α-mannosidases with fluorescently-labeled polynucleotide probes using direct-geneFISH. Reliable in situ localization of single-copy genes was achieved with an efficiency up to 74% not only in the flavobacterial strains Polaribacter Hel1_33_49 and Formosa Hel1_33_131 but also in planktonic samples from the North Sea. In combination with high-resolution microscopy, direct-geneFISH gave visual evidence of the contrasting lifestyles of closely related Polaribacter species in those samples and allowed for the determination of gene distribution among attached and free-living cells. We also detected highly similar GH92 genes in yet unidentified taxa by broadening probe specificities, enabling a visualization of the functional trait in subpopulations across the borders of species and genera. Such a quantitative insight into the niche separation of flavobacterial taxa complements our understanding of the ecology of polysaccharide-degrading bacteria beyond omics-based techniques on a single-cell level.


EDIS ◽  
2017 ◽  
Vol 2017 (2) ◽  
pp. 8
Author(s):  
Zane Grabau

This 8-page fact sheet written by Zane J. Grabau and published in January 2017 by the UF Department of Entomology and Nematology explains how to diagnose and manage nematode problems in cotton production.­http://edis.ifas.ufl.edu/ng015


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