Host Range Distribution Research Articles

Unveiling the Host-range Distribution of Pasteuria penetrans Against Various Root-knot Nematode, Meloidogyne spp.

Root-knot nematodes (Meloidogyne spp.) are economically significant plant parasites causing extensive damage to various crops globally. Their sedentary endoparasitic nature, facilitated by a stylet, induces the formation of giant cells in plant roots, leading to characteristic symptoms such as galling, stunting, wilting, and reduced yield. To manage these pests, a combination of cultural, biological, and chemical methods is employed. Among biological control agents, Pasteuria penetrans, an obligate hyperparasitic bacterium, which shows effectiveness and primarily targets root-knot nematodes and exhibits specificity towards certain species or strains within the Meloidogyne genus. The conductance of a host range study is pivotal in understanding the potential efficacy and specificity of biocontrol agents against target pests. The current study aims to explore the host range of P. penetrans its effectiveness against three nematode species, Meloidogyne incognita, Meloidogyne enterolobii. Meloidogyne graminicola tested its efficacy against various host crops. The outcome of the current study gives the successful attachment of P. penetrans against M. incognita, whereas M. enterolobii were not shown promising results and also M. graminicola was identified as a non-host for this bacterium. And also, the results of this study provide valuable insights into the applicability of P. penetrans as a biological control agent.

Physiopathological studies, characterization and yield loss assessment of Curvularia leaf spot of maize (Zea mays)

Curvularia leaf spot of maize (Zea mays L.) caused by Curvularia lunata var. aeria is one of serious foliar diseases of maize. An experimental conducted during 2016–17 at research farm of Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan found that Curvularia showed considerable variation in growth characteristics, colony diameter and rate of sporulation. The maximum colony diameter was 90.0 mm with 11.0 × 104 conidia/mm2. The size measurement of conidia of C. lunata-01 was in range of 60.1–91.9 μm length and width range was 16.2–23.5 μm. Length and width of isolate C. lunata-02 recorded in range of 55.6–79.5 and 14.2–22.5 μm respectively. Host range distribution showed that pathogen has a wide host range in many crops and weeds under artificial inoculation. Seed transmission results showed that Local surya exhibited higher 66.66% seeds borne inoculam while Pratap makka-3 have 40.00% seed borne inoculums of pathogen. Physiopathological studies shows that 25±2°C was optimum temperature for both the isolates. Maximum mycelial growth and sporulation was found at 90% RH followed by 80% in both the isolates. The 22.29% losses in yield due to Curvularia leaf spot was assessed by using Le Clerg model. The present study of pathogen biology could be used by plant pathologists to develop or redesign management strategies for the maize growers.

First report of Plum bark necrosis stem pitting-associated virus infecting grapevine in China

BackgroundVirus disease is one of the main diseases in grapevine, and there has been no report on Plum bark necrosis and stem pitting-associated virus infecting grapevine in China.ObjectiveThe leaf samples of grapevine cultivar 'Cabernet Gernischt' were collected from Shandong province, which the leaves suffered from viral-like symptoms with spotting and crinkle.MethodsSmall RNA-seq combined with reverse transcription PCR (RT-PCR) were performed to detect the potential viruses in these field samples. Phylogenetic tree was constructed using the neighbor joining method in MEGA 5.1ConclusionsThis is the first report of PBNSPaV infecting grapevine in China, contributing to a better understanding of the epidemiology and host range distribution of this pathogen.

Gut Bacterial Communities of Dendroctonus valens and D. mexicanus (Curculionidae: Scolytinae): A Metagenomic Analysis across Different Geographical Locations in Mexico.

Dendroctonus bark beetles are a worldwide significant pest of conifers. This genus comprises 20 species found in North and Central America, and Eurasia. Several studies have documented the microbiota associated with these bark beetles, but little is known regarding how the gut bacterial communities change across host range distribution. We use pyrosequencing to characterize the gut bacterial communities associated with six populations of Dendroctonus valens and D. mexicanus each across Mexico, determine the core bacteriome of both insects and infer the metabolic pathways of these communities with Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) to evaluate whether these routes are conserved across geographical locations. Our results show that the β-diversity with UniFrac unweighted varies among locations of both bark beetles mainly due to absence/presence of some rare taxa. No association is found between the pairwise phylogenetic distance of bacterial communities and geographic distance. A strict intraspecific core bacteriome is determined for each bark beetle species, but these cores are different in composition and abundance. However, both bark beetles share the interspecific core bacteriome recorded previously for the Dendroctonus genus consisting of Enterobacter, Pantoea, Providencia, Pseudomonas, Rahnella, and Serratia. The predictions of metabolic pathways are the same in the different localities, suggesting that they are conserved through the geographical locations.

Molecular epidemiology, associated risk factors, and phylogenetic analysis of anaplasmosis in camel

Camel Anaplasmosis is caused by members of family Anaplasmatacae, a tick transmitted, obligate intracellular bacteria. The etiological bacteria are transmitted by ixodid tick species. The species have multi host range distribution that is why it is crucial to diagnose it timely. The aim of present study was to investigate the molecular epidemiology i.e. prevalence and risk factors analysis of camel anaplasmosis. Furthermore, variations in hematological standards were also evaluated. The study found an overall 13.33% prevalence in camels. The confirmation of PCR positive samples for Anaplasma spp. was made through sequencing, the study isolatesshowed high homology with Iranian, Chinese, Philippines and South African isolates of Anaplasmatacae (Accession numbers'; KX765882, KP062964, KY242456, LC007100 and U54806) on BLAST queries. The phylogenetic analysis revealedthree study isolates of present study clustered with each other and the cluster was found closer to Chinese isolate of A. phagocytophilum (KY242456), A. marginale (KU586048), and Mongolian isolates of A. ovis (LC194134). Two of the isolates resembled Iranian isolate of Candidatus Anaplasmacamelii (KX765882), while one isolate resembled with Chinese isolates of A. Platys (KX987336) and Croatian isolates of A. Platys (KY114935). The key risk factors odds ratio (OR>1) identified for occurrence of camel anaplasmosis using regression model found sex and age of animal, previous tick history, tick infestation and tick control status, housing type, cracks in walls, rearing system and other species in surrounding as the key risk factors. The hematological parameters like lymphocytes, monocytes, granulocytes and platelets count were significantly decreased (p < 0.05) in diseased camels than healthy. This is the first ever molecular data on camel anaplasmosis in Pakistan. The disease should be monitored unceasingly as the etiologies have multi host distribution. Prompt attention should be offered to animals because neutropenia, lymphopenia and thrombocytopenia can exacerbate the disease by making the animal predisposed to otherdiseases.

Bayesian Inference of the Evolution of a Phenotype Distribution on a Phylogenetic Tree.

The distribution of a phenotype on a phylogenetic tree is often a quantity of interest. Many phenotypes have imperfect heritability, so that a measurement of the phenotype for an individual can be thought of as a single realization from the phenotype distribution of that individual. If all individuals in a phylogeny had the same phenotype distribution, measured phenotypes would be randomly distributed on the tree leaves. This is, however, often not the case, implying that the phenotype distribution evolves over time. Here we propose a new model based on this principle of evolving phenotype distribution on the branches of a phylogeny, which is different from ancestral state reconstruction where the phenotype itself is assumed to evolve. We develop an efficient Bayesian inference method to estimate the parameters of our model and to test the evidence for changes in the phenotype distribution. We use multiple simulated data sets to show that our algorithm has good sensitivity and specificity properties. Since our method identifies branches on the tree on which the phenotype distribution has changed, it is able to break down a tree into components for which this distribution is unique and constant. We present two applications of our method, one investigating the association between HIV genetic variation and human leukocyte antigen and the other studying host range distribution in a lineage of Salmonella enterica, and we discuss many other potential applications.

The chiropteran haemosporidian Polychromophilus melanipherus: A worldwide species complex restricted to the family Miniopteridae

This paper attempts to expand on the current knowledge regarding the evolutionary history of bat haemosporidian parasites. Using modern molecular tools as adjuncts to existing morphological descriptions, our understanding of the diversity of these parasites is discussed. The biogeography and host range distribution together with possible host-parasite interactions remain to be evaluated in more detail. Using a nested-PCR cytochrome b mitochondrial gene approach, we established a screening programme and survey of several months duration for haemosporidian parasites in four central African bat species living in an ecological community. The aim of the study was to describe parasites morphologically and molecularly, together with parasite prevalence variations over time, and evaluate parasite host-specificity in these sympatric cave bats. Over the survey period, Polychromophilus melanipherus was the only haemosporidian parasite identified in Miniopterus inflatus, with a continuous molecular prevalence of at least 60%. Molecular phylogenetic analyses show that P. melanipherus is a monophyletic group infecting Miniopterus bats which is, a sister group to P. murinus and Polychromophilus spp. This monophyletic group is composed of different cyt b haplotypes molecularly distantly related (but morphologically similar), circulating without geographic or host species distinction. This suggests that P. melanipherus is a species complex restricted to the family Miniopteridae. The phylogenetic analysis confirms that Polychromophilus parasites are distributed worldwide and supports the view that they are more closely related to avian haemosporidian parasites.

Distribution host range and flight pattern of the lettuce aphid in New Zealand

The lettuce aphid (Nasonovia ribisnigri) was first reported in New Zealand on lettuce (Lactuca sativa) in Canterbury in March 2002 During autumn 2002 the lettuce aphid was collected in three suction traps (75 m high) around Canterbury Within one year it had spread to all of the main lettuce growing regions of the country mostly as a result of transporting aphidinfested fresh lettuce or lettuce seedling transplants to these regions It was found on its primary host Ribes spp (eg currants and gooseberries) and moved to its secondary hosts (eg lettuce and weeds) in late spring having survived the winter in sexual and asexual forms Up to 73 lettuce aphids per flower head were found on flower buds and flowers of some widely distributed weeds in New Zealand including Crepis spp Hieracium spp Cichorium intybus and Lactuca virosa during summer and autumn 2003 This infestation resulted in a number of crops being deemed unfit for marketing