scholarly journals Characterisation of the Viral Community Associated with the Alfalfa Weevil (Hypera postica) and Its Host Plant, Alfalfa (Medicago sativa)

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 791
Author(s):  
Sarah François ◽  
Aymeric Antoine-Lorquin ◽  
Maximilien Kulikowski ◽  
Marie Frayssinet ◽  
Denis Filloux ◽  
...  

Advances in viral metagenomics have paved the way of virus discovery by making the exploration of viruses in any ecosystem possible. Applied to agroecosystems, such an approach opens new possibilities to explore how viruses circulate between insects and plants, which may help to optimise their management. It could also lead to identifying novel entomopathogenic viral resources potentially suitable for biocontrol strategies. We sampled the larvae of a natural population of alfalfa weevils (Hypera postica), a major herbivorous pest feeding on legumes, and its host plant alfalfa (Medicago sativa). Insect and plant samples were collected from a crop field and an adjacent meadow. We characterised the diversity and abundance of viruses associated with weevils and alfalfa, and described nine putative new virus species, including four associated with alfalfa and five with weevils. In addition, we found that trophic accumulation may result in a higher diversity of plant viruses in phytophagous pests compared to host plants.

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 263 ◽  
Author(s):  
Véronique Ziegler-Graff

Plant viruses rely on both host plant and vectors for a successful infection. Essentially to simplify studies, transmission has been considered for decades as an interaction between two partners, virus and vector. This interaction has gained a third partner, the host plant, to establish a tripartite pathosystem in which the players can react with each other directly or indirectly through changes induced in/by the third partner. For instance, viruses can alter the plant metabolism or plant immune defence pathways to modify vector’s attraction, settling or feeding, in a way that can be conducive for virus propagation. Such changes in the plant physiology can also become favourable to the vector, establishing a mutualistic relationship. This review focuses on the recent molecular data on the interplay between viral and plant factors that provide some important clues to understand how viruses manipulate both the host plants and vectors in order to improve transmission conditions and thus ensuring their survival.


Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1153 ◽  
Author(s):  
Linda J. S. Allen ◽  
Vrushali A. Bokil ◽  
Nik J. Cunniffe ◽  
Frédéric M. Hamelin ◽  
Frank M. Hilker ◽  
...  

Co-infection of plant hosts by two or more viruses is common in agricultural crops and natural plant communities. A variety of models have been used to investigate the dynamics of co-infection which track only the disease status of infected and co-infected plants, and which do not explicitly track the density of inoculative vectors. Much less attention has been paid to the role of vector transmission in co-infection, that is, acquisition and inoculation and their synergistic and antagonistic interactions. In this investigation, a general epidemiological model is formulated for one vector species and one plant species with potential co-infection in the host plant by two viruses. The basic reproduction number provides conditions for successful invasion of a single virus. We derive a new invasion threshold which provides conditions for successful invasion of a second virus. These two thresholds highlight some key epidemiological parameters important in vector transmission. To illustrate the flexibility of our model, we examine numerically two special cases of viral invasion. In the first case, one virus species depends on an autonomous virus for its successful transmission and in the second case, both viruses are unable to invade alone but can co-infect the host plant when prevalence is high.


Author(s):  
Marcin W. Zielonka ◽  
Tom W. Pope ◽  
Simon R. Leather

Abstract The carnation tortrix moth, Cacoecimorpha pronubana (Hübner, [1799]) (Lepidoptera: Tortricidae), is one of the most economically important insect species affecting the horticultural industry in the UK. The larvae consume foliage, flowers or fruits, and/or rolls leaves together with silken threads, negatively affecting the growth and/or aesthetics of the crop. In order to understand the polyphagous behaviour of this species within an ornamental crop habitat, we hypothesized that different host plant species affect its life history traits differently. This study investigated the effects of the host plant species on larval and pupal durations and sizes, and fecundity (the number of eggs and the number and size of egg clutches). At 20°C, 60% RH and a 16L:8D photoperiod larvae developed 10, 14, 20 and 36 days faster when reared on Christmas berry, Photinia (Rosaceae), than on cherry laurel, Prunus laurocerasus (Rosaceae), New Zealand broadleaf, Griselinia littoralis (Griseliniaceae), Mexican orange, Choisya ternata (Rutaceae), and firethorn, Pyracantha angustifolia (Rosaceae), respectively. Female pupae were 23.8 mg heavier than male pupae, and pupal weight was significantly correlated with the duration of larval development. The lowest and the highest mean numbers of eggs were produced by females reared on Pyracantha (41) and Photinia (202), respectively. Clutch size differed significantly among moths reared on different host plants, although the total number of eggs did not differ. This study showed that different ornamental host plants affect the development of C. pronubana differently. Improved understanding of the influence of host plant on the moth's life history parameters measured here will help in determining the economic impact that this species may have within the ornamental plant production environment, and may be used in developing more accurate crop protection methodologies within integrated pest management of this insect.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Belén Cotes ◽  
Gunda Thöming ◽  
Carol V. Amaya-Gómez ◽  
Ondřej Novák ◽  
Christian Nansen

AbstractRoot-associated entomopathogenic fungi (R-AEF) indirectly influence herbivorous insect performance. However, host plant-R-AEF interactions and R-AEF as biological control agents have been studied independently and without much attention to the potential synergy between these functional traits. In this study, we evaluated behavioral responses of cabbage root flies [Delia radicum L. (Diptera: Anthomyiidae)] to a host plant (white cabbage cabbage Brassica oleracea var. capitata f. alba cv. Castello L.) with and without the R-AEF Metarhizium brunneum (Petch). We performed experiments on leaf reflectance, phytohormonal composition and host plant location behavior (behavioral processes that contribute to locating and selecting an adequate host plant in the environment). Compared to control host plants, R-AEF inoculation caused, on one hand, a decrease in reflectance of host plant leaves in the near-infrared portion of the radiometric spectrum and, on the other, an increase in the production of jasmonic, (+)-7-iso-jasmonoyl-l-isoleucine and salicylic acid in certain parts of the host plant. Under both greenhouse and field settings, landing and oviposition by cabbage root fly females were positively affected by R-AEF inoculation of host plants. The fungal-induced change in leaf reflectance may have altered visual cues used by the cabbage root flies in their host plant selection. This is the first study providing evidence for the hypothesis that R-AEF manipulate the suitability of their host plant to attract herbivorous insects.


Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 375-387 ◽  
Author(s):  
N. Aileen Ryan ◽  
Peter Jones

AbstractSeventy bacteria, isolated from the rhizosphere of the potato cyst nematode (PCN) host plant, potato, were cultured in the presence and absence of potato root leachate (PRL) and the resultant culture filtrates were analysed for their ability to affect the hatch in vitro of the two PCN species. Of the isolates tested, nine had a significant effect on PCN hatch. Six affected Globodera pallida hatch and three affected G. rostochiensis hatch. Five of the isolates significantly increased hatch only when cultured in the presence of PRL. Three of the isolates decreased PCN hatch significantly in PRL. Only one isolate increased hatch significantly in the absence of PRL. No isolate affected the hatch of both species. Six of the nine isolates that significantly affected PCN hatch had been pre-selected by culturing on PRL. Bacterial isolates from PCN non-hosts (14 from wheat, 17 from sugar beet) were also tested for hatching activity. The principal effect of the hatch-active isolates from the PCN non-host plants was to increase PCN hatch in the presence of PRL. In contrast to the host bacteria results, the isolates from non-host plants affected only G. rostochiensis hatch (three wheat isolates and four sugar beet isolates significantly increased G. rostochiensis hatch); no such isolate affected G. pallida hatch significantly in the presence of PRL. Ten isolates (32%) from non-host plants had the ability to increase significantly the hatch of PCN in the absence of PRL (eight of these affected G. rostochiensis hatch and four affected G. pallida hatch), compared to only one bacterial isolate (1%) from a host plant. The majority of the isolates from non-hosts produced PCN species-specific effects, as with the bacteria isolated from potatoes, although two wheat isolates increased the hatch of both species significantly in the absence of PRL. Of 20 hatch-active bacterial isolates (from all three plants) identified, 70% were Bacillus spp. Other genera identified were Arthrobacter , Acinetobacter and Staphylococcus .


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiao-Bin Shi ◽  
Shuo Yan ◽  
Chi Zhang ◽  
Li-Min Zheng ◽  
Zhan-Hong Zhang ◽  
...  

Abstract Background Most plant viruses rely on vectors for their transmission and spread. One of the outstanding biological questions concerning the vector-pathogen-symbiont multi-trophic interactions is the potential involvement of vector symbionts in the virus transmission process. Here, we used a multi-factorial system containing a non-persistent plant virus, cucumber mosaic virus (CMV), its primary vector, green peach aphid, Myzus persicae, and the obligate endosymbiont, Buchnera aphidicola to explore this uncharted territory. Results Based on our preliminary research, we hypothesized that aphid endosymbiont B. aphidicola can facilitate CMV transmission by modulating plant volatile profiles. Gene expression analyses demonstrated that CMV infection reduced B. aphidicola abundance in M. persicae, in which lower abundance of B. aphidicola was associated with a preference shift in aphids from infected to healthy plants. Volatile profile analyses confirmed that feeding by aphids with lower B. aphidicola titers reduced the production of attractants, while increased the emission of deterrents. As a result, M. persicae changed their feeding preference from infected to healthy plants. Conclusions We conclude that CMV infection reduces the B. aphidicola abundance in M. persicae. When viruliferous aphids feed on host plants, dynamic changes in obligate symbionts lead to a shift in plant volatiles from attraction to avoidance, thereby switching insect vector’s feeding preference from infected to healthy plants.


2005 ◽  
Vol 137 (4) ◽  
pp. 488-491
Author(s):  
Qodrat Sabahi ◽  
Khalil Talebi

The alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), can severely damage the first cutting of alfalfa, Medicago sativa L. (Fabaceae), in much of Iran. The pest has been parasitized by several parasitoids including Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae), a gregarious larval endoparasitoid. This wasp can parasitize up to 30% of weevil larvae in alfalfa fields in northern Iran. It produces three to four generations per year, and the female prefers the fourth instar of the host for oviposition. Each female lays 2 to 22 eggs per host, which hatch within 47–60 h. The life cycle is completed in about 2 weeks, upon pupation inside the host. This species is predominantly present during the summer months in alfalfa fields (Streams and Fuester 1967).


2019 ◽  
Vol 9 (3) ◽  
pp. 151-159
Author(s):  
Magdalena Sunarti Pareira ◽  
Irdika Mansur ◽  
Dewi Wulandari

The sandalwood tree (Santalum album Linn.) is an important tree species as well as a primadonna for the people of East Nusa Tenggara (NTT). It has high economic value for its aromatic wood and essential oil content that have a very distinctive aroma used to make various products such as handicrafts, woodcarvings, incense, and oil for the perfume and cosmetics industry. Sandalwood is a semi parasite plant that part of its life phase requires a host plant to get the nutrients and water. There are many types of host plants that have been used, among others, Casuarina equisetifolia, Acacia mangium, Terminalia microcarpa, Sesbania grandiflora, Alternanthera sp and Capsicum annum. In this research will be tested to try sandalwood planted with Cymbopogon nardus host plants, in terms of economics can provide benefits.Arbuscular mycorrhizal fungi (AMF) is a group of fungi from glomeromycota phylum that can symbiosis mutualism with root system of high level plant. The working principle of the mycorrhiza is to infect the root system of the host plant, producing intensive hyphae tissue so that the plant containing mycorrhiza will be able to increase the capacity in nutrient uptake. The utilization of host plants Alternanthera sp, Capsicum annum, and its application with AMF is the best solution to overcome the problem of developing sandalwood in TTU on the nursery. The purpose of this study was to analyze the effectiveness of AMF and utilization of the atsiri host plant to increase the growth of sandalwood seedlings in TTU. This study was designed using a complete random method (RAL) in split plot design. If the treatment has a significant effect then followed by Duncan Multiple Range Test (DMRT). Parameters observed were height (cm), number of leaf, diameter of sandalwood (mm), dry weight of root, seed quality index, ratio of root buds, and haustorium observation of Sandalwood, and also number of spore, root colonization and AMF dependency of Sandalwood.The results showed that the treatment of AMF with Capsicum annum host plant was 19.8 of high, number of leaf 18.9 on FMA treatment with host plant Capsicum annum, diameter of stem 2.24 mm on Alternanthera sp host treatments without AMF and 1.83 mm at AMF treatment with host plant Capsicum annum, dry weight of buds 2.00g on AMF treatment with Capsicum annum host plant, dry weight of roots AMF (M1) with alternanthera sp 0.70 g, root buds ratio of AMF with host plant alternanthera sp 4.05, seed quality index AMF with Alternanthera sp 4.16 and 82 % of root colonization on AMF with host plant Capsicum annum.Keywords: Santalum album Linn., AMF, host plant.


Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1808
Author(s):  
Saptarshi Ghosh ◽  
Murad Ghanim

Many plant viruses depend on insect vectors for their transmission and dissemination. The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important virus vectors, transmitting more than four hundred virus species, the majority belonging to begomoviruses (Geminiviridae), with their ssDNA genomes. Begomoviruses are transmitted by B. tabaci in a persistent, circulative manner, during which the virus breaches barriers in the digestive, hemolymph, and salivary systems, and interacts with insect proteins along the transmission pathway. These interactions and the tissue tropism in the vector body determine the efficiency and specificity of the transmission. This review describes the mechanisms involved in circulative begomovirus transmission by B. tabaci, focusing on the most studied virus in this regard, namely the tomato yellow leaf curl virus (TYLCV) and its closely related isolates. Additionally, the review aims at drawing attention to the recent knowhow of unorthodox virus—B. tabaci interactions. The recent knowledge of whitefly-mediated transmission of two recombinant poleroviruses (Luteoviridae), a virus group with an ssRNA genome and known to be strictly transmitted with aphids, is discussed with its broader context in the emergence of new whitefly-driven virus diseases.


2019 ◽  
Author(s):  
Yu Okamura ◽  
Ai Sato ◽  
Natsumi Tsuzuki ◽  
Masashi Murakami ◽  
Hanna Heidel-Fischer ◽  
...  

AbstractAdaptive traits that enable organisms to conquer novel niches and experience subsequent diversification are ecologically and evolutionarily important. The larvae of Pieris butterflies express nitrile-specifier proteins (NSPs), a key innovation for overcoming the glucosinolate (GLS)-myrosinase-based defense system of their Brassicales host-plants. NSPs are a member of the NSP-like gene family, which includes the major allergen (MA) protein, a paralog of NSP with a GLS-disarming function, and a single domain major allergen (SDMA) protein, whose function is unknown. The arms-race between a highly variable host-plant defense system and members of the NSP-like gene family is suggested to mediate diversification in both Pierid butterflies and Brassicales plants. Here, we combined feeding experiments using 25 Brassicaceae plants and five Pieris species with larval transcriptome data to investigate the evolutionary forces acting on NSP-like gene family members associated with patterns of host-plant usage. Although we observed significantly elevated nonsynonymous to synonymous substitution ratios in NSPs, no such pattern was observed in MAs or SDMAs. Furthermore, we found a signature of positive selection of NSP at a phylogenetic branch which reflects different host-plant preferences. Our data indicate that NSPs have evolved in response to shifting preferences for host plants among five Pieris butterflies, whereas MAs and SDMAs appear to have more conserved functions. Our results show that the evolution and functional differentiation of key genes used in host-plant adaptation play a crucial role in the chemical arms-race between Pieris butterflies and their Brassicales host-plants.


Sign in / Sign up

Export Citation Format

Share Document