Range Of Host Plants Research Articles

Multiple facets of cutting-edge mycorrhizal research: 11th International Conference on Mycorrhiza (ICOM 11), Beijing, China, August 2022: 11th International Conference on Mycorrhiza (ICOM 11), Beijing, China, 1-5 August 2022.

Multiple facets of cutting-edge mycorrhizal research: 11th International Conference on Mycorrhiza (ICOM 11), Beijing, China, August 2022: 11th International Conference on Mycorrhiza (ICOM 11), Beijing, China, 1-5 August 2022.

Population growth of Tetranychus truncatus (Acari: Tetranychidae) on different drought-tolerant potato cultivars.

Tetranychus truncatus Ehara (Acari: Tetranychidae) has become one of the major phytophagous pests in China in recent years, and is found on a wide range of host plants. However, little information is available on the population performance of this arthropod pest on potatoes. In this study, we explored the population growth of T. truncatus on two drought-tolerant potato (Solanum tuberosum L.) cultivars under laboratory conditions using the age-stage, two-sex life table. Tetranychus truncatus completed its entire life history on both potato cultivars tested, Holland 15 and Longshu 10. There was no significant difference between two potato cultivars in developmental duration. Tetranychus truncatus had shorter adult longevity (20.61 days), adult female longevity (20.41 days), and total female longevity (33.66 days) on Longshu 10 than Holland 15 (21.16 days, 21.19 days, and 34.38 days, respectively). However, it exhibited a higher preadult survival rate, higher fecundity (F = 88.32 eggs per female), and relatively higher population parameters when reared on Longshu 10 than on Holland 15 (F = 75.70 eggs per female). Growth projection also showed that the population size of T. truncatus on Longshu 10 (expand 750-fold) was larger than that on Holland 15 (expand 273-fold) after 60 days. Our results demonstrate that the drought-sensitive potato variety, Holland 15, is relatively resistant to T. truncatus compared with the drought-tolerant variety, Longshu 10, and suggest that T. truncatus exhibited a trade-off between longevity and reproduction on both potato cultivars. Our findings provide information on population prediction, which may aid the management of this pest mite species of potatoes.

Two new species of Diaporthe (Diaporthaceae, Diaporthales) in China.

Species of Diaporthe have been reported as plant endophytes, pathogens and saprobes on a wide range of plant hosts. Strains of Diaporthe were isolated from leaf spots of Smilaxglabra and dead culms of Xanthiumstrumarium in China, and identified based on morphology and molecular phylogenetic analyses of combined internal transcribed spacer region (ITS), calmodulin (cal), histone H3 (his3), translation elongation factor 1-alpha (tef1) and β-tubulin (tub2) loci. As a result, two new species named Diaportherizhaoensis and D.smilacicola are identified, described and illustrated in the present study.

The earliest pollen-loaded insects from the Lower Permian of Russia.

Recent fossil discoveries suggest that the coevolution of insect pollinators and gymnosperms started long before the appearance of flowering plants. One of the keys to understanding the origins of pollination relationships is fossil insects with gymnosperm pollen attached to the body surface. Such fossils are exceedingly rare to find, especially from the Palaeozoic, a time when ambers with insect inclusions were absent. Here, we report compression fossils of Early Permian tillyardembiid insects (Polyneoptera) preserved with pollen on their heads, thoraces, legs and abdomens. This is the earliest finding of pollen-bearing insects, predating the previous oldest record from the Middle Jurassic by ca 120 Ma. Judging by the pollen composition, tillyardembiids visited a narrow range of host plants, including Rufloriaceae (Cordaitales). While it is impossible to say for certain whether tillyardembiids as pollen consumers contributed to pollination, a trophic specialization of this kind could be considered an evolutionary precursor of pollination mutualism.

Insights into the genome of Methylobacterium sp. NMS14P, a novel bacterium for growth promotion of maize, chili, and sugarcane.

A novel methylotrophic bacterium designated as NMS14P was isolated from the root of an organic coffee plant (Coffea arabica) in Thailand. The 16S rRNA sequence analysis revealed that this new isolate belongs to the genus Methylobacterium, and its novelty was clarified by genomic and comparative genomic analyses, in which NMS14P exhibited low levels of relatedness with other Methylobacterium-type strains. NMS14P genome consists of a 6,268,579 bp chromosome, accompanied by a 542,519 bp megaplasmid and a 66,590 bp plasmid, namely pNMS14P1 and pNMS14P2, respectively. Several genes conferring plant growth promotion are aggregated on both chromosome and plasmids, including phosphate solubilization, indole-3-acetic acid (IAA) biosynthesis, cytokinins (CKs) production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, sulfur-oxidizing activity, trehalose synthesis, and urea metabolism. Furthermore, pangenome analysis showed that NMS14P possessed the highest number of strain-specific genes accounting for 1408 genes, particularly those that are essential for colonization and survival in a wide array of host environments, such as ABC transporter, chemotaxis, quorum sensing, biofilm formation, and biosynthesis of secondary metabolites. In vivo tests have supported that NMS14P significantly promoted the growth and development of maize, chili, and sugarcane. Collectively, NMS14P is proposed as a novel plant growth-promoting Methylobacterium that could potentially be applied to a broad range of host plants as Methylobacterium-based biofertilizers to reduce and ultimately substitute the use of synthetic agrochemicals for sustainable agriculture.

Lethal and sublethal effects of synthetic and bioinsecticides toward the invasive ambrosia beetle Xylosandrus compactus.

Exotic ambrosia beetles are emerging widespread pests of several wild and managed trees and shrubs. Xylosandrus compactus (Eichhoff) is one of the most invasive species causing damage to a broad range of host plants. Little information is available on its control, including the impact of insecticides. Bioassays were conducted to evaluate the potential of four bioinsecticides and seven synthetic insecticides in controlling X. compactus. Beetle mortality and sublethal effects on tunneling, cultivation of the mutualist fungus and reproduction were assessed. Concentration-mortality curves were determined for all tested insecticides. Lambda-cyhalothrin was the most toxic insecticide, showing the lowest estimated 90% and 50% lethal concentrations (LC90 and LC50 ), followed by deltamethrin and thiamethoxam. Acetamiprid caused the highest levels of mortality and brood size reduction under extended laboratory conditions. Moreover, acetamiprid, thiamethoxam and lambda-cyhalothrin caused the greatest mortality and, together with deltamethrin, strongly affected progeny occurrence inside infested galleries and beetle brood size. Among the bioinsecticides, pyrethrins significantly affected beetle survival under laboratory conditions, but not brood size in extended laboratory bioassays. Some of the tested insecticides had significant lethal and sublethal effects only when beetles were exposed to fresher residues, highlighting differences in toxicity persistence. This study provides first baseline toxicity data for synthetic insecticides and bioinsecticides with different modes of action and origin toward X. compactus, and the first evidence that several insecticides can cause multiple sublethal effects on this pest. These findings can help in building suitable integrated pest management packages against this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Plant Metabolites Affect Fusarium proliferatum Metabolism and In Vitro Fumonisin Biosynthesis.

Fusarium proliferatum is a common hemi-biotrophic pathogen that infect a wide range of host plants, often leading to substantial crop loss and yield reduction. F. proliferatum synthesizes various mycotoxins, and fumonisins B are the most prevalent. They act as virulence factors and specific effectors that elicit host resistance. The effects of selected plant metabolites on the metabolism of the F. proliferatum strain were analyzed in this study. Quercetin-3-glucoside (Q-3-Glc) and kaempferol-3-rutinoside (K-3-Rut) induced the pathogen's growth, while DIMBOA, isorhamnetin-3-O-rutinoside (Iso-3-Rut), ferulic acid (FA), protodioscin, and neochlorogenic acid (NClA) inhibited fungal growth. The expression of seven F. proliferatum genes related to primary metabolism and four FUM genes was measured using RT-qPCR upon plant metabolite addition to liquid cultures. The expression of CPR6 and SSC1 genes was induced 24 h after the addition of chlorogenic acid (ClA), while DIMBOA and protodioscin reduced their expression. The transcription of FUM1 on the third day of the experiment was increased by all metabolites except for Q-3-Glc when compared to the control culture. The expression of FUM6 was induced by protodioscin, K-3-Rut, and ClA, while FA and DIMBOA inhibited its expression. FUM19 was induced by all metabolites except FA. The highest concentration of fumonisin B1 (FB1) in control culture was 6.21 µg/mL. Protodioscin did not affect the FB content, while DIMBOA delayed their synthesis/secretion. Flavonoids and phenolic acids displayed similar effects. The results suggest that sole metabolites can have lower impacts on pathogen metabolism and mycotoxin synthesis than when combined with other compounds present in plant extracts. These synergistic effects require additional studies to reveal the mechanisms behind them.

Comparative Phenotypic, Genomic, and Transcriptomic Analyses of Two Contrasting Strains of the Plant Beneficial Fungus Trichoderma virens.

Trichoderma virens is a beneficial fungus that helps plants fight pathogens and abiotic stresses and thereby enhances crop yields. Unlike other Trichoderma spp., there are two well-defined strains (P and Q) of T. virens, classified by secondary metabolites profiling, primarily the biosynthesis of the nonribosomal, strong antimicrobial agents gliotoxin (Q) and gliovirin (P). We have studied the phenotypic and biocontrol properties of two well-studied representative isolates (T. virens Gv29-8 and T. virens GvW/IMI304061) that represent a Q strain and a P strain of T. virens, respectively. We refined the genome assembly of the P strain using nanopore technology, and we compared it with the Q strain. The differences between the genomes include gene expansion in the Q strain. T. virens Gv29-8 is weaker than GvW as a mycoparasite on the broad host-range plant pathogen Sclerotium rolfsii, and it is ineffective as a biocontrol agent when applied to pathogen-infested soil. T. virens Gv29-8 proved to be phytotoxic to Arabidopsis seedlings, whereas the effect of T. virens GvW was not major. Both strains colonized the surface and outer cortex layer of tomato roots, with about 40% higher colonization by T. virens Gv29-8. T. virens Gv29-8 induced the expression of a larger set of tomato genes than did T. virens GvW, although some tomato genes were uniquely induced in response to T. virens GvW. We studied the comparative transcriptome response of T. virens Gv29-8 and T. virens GvW to S. rolfsii. A larger set of genes was regulated in T. virens GvW than in T. virens Gv29-8 in the presence of the plant pathogen. IMPORTANCE Trichoderma virens populations that were earlier classified into two strains (P and Q) based on secondary metabolites profiling are also phenotypically and genetically distinct, with the latter being ineffective in controlling the devastating, broad host range plant pathogen Sclerotium rolfsii. The two strains also provoke distinct as well as overlapping transcriptional responses to the presence of the plant and the pathogen. This study enriches our knowledge of Trichoderma-plant-pathogen interactions and identifies novel candidate genes for further research and deployment in agriculture.

Predator efficacy and attraction to herbivore-induced volatiles determine insect pest selection of inferior host plant

Unlike mammals, most invertebrates provide no direct parental care for their progeny, which makes a well-selected oviposition site crucial. However, little is known about the female evaluation of opportunities and threats during host selection. Leveraging the wide range of host plants used by the polyphagous pest, Spodoptera littoralis, we investigate oviposition choice between two plants of different nutritional quality. Females prefer to lay their eggs on the host plant, which has inferior larval development and more natural enemies but provides lower predation rates. On the superior host plant, a major predator shows more successful search behavior and is more attracted to herbivore-induced volatiles. Our findings show that predator efficacy and odor-guided attraction, rather than predator abundance, determine enemy free space. We postulate that predators' behaviors contribute to the weak correlation between preference and performance during host plant selection in S.littoralis and in polyphagous insects in general.

Development of SNP molecular markers associated with resistance to reniform nematode in soybean using KASP genotyping

Reniform nematode (Rotylenchulus reniformis, Linford and Oliveira) is a sedentary, semi-endoparasite that infects a wide range of plant hosts and is one of the top three nematode pathogens affecting soybean in the southeastern United States. Previous studies have linked resistance to reniform nematode in soybean to two quantitative trait loci on chromosomes 11 and 18. A Kompetitive Allele-Specific PCR (KASP) assay was designed using SNP markers within these two regions to distinguish reniform nematode-resistant soybean based on genotype. A collection of 44 soybean plant introductions with resistant phenotype to reniform nematode and 40 susceptible soybean lines were genotyped at the two target loci to validate the KASP assay design. Of the 44 observed resistant lines, two carried the susceptible genotype; PI 438489B at the locus on chromosome 18 and PI 495017C on chromosome 11. Of the 40 observed susceptible soybean lines, only 25 had the expected susceptible genotype at the loci on chromosome 18 and 13 on chromosome 11. Our KASP assay was 68% accurate in predicting the phenotype of 84 soybean accessions based on their genotype at the SNP marker on chromosome 18 and 83% accurate at chromosome 11. These results indicate a moderate correlation of soybean SNP markers GlyREN18_46 and GlyREN11_190 with reniform nematode resistance. Further research is required to improve the accuracy of KASP assays to predict soybean response to reniform nematode, particularly host susceptibility.

Bottom-up and top-down pressures mediate competition between two generalist insects.

The effects of competition can have far-reaching consequences for individuals, populations, and communities and therefore we should strive toward a deeper understanding of competitive interactions. In some cases, dietary generalists may be predicted to experience weak competition effects because of their ability to use a wide range of host plants. However, competition between insects frequently occurs indirectly, which can hinder insects' abilities to avoid competitive interactions. Therefore, competition may be as strong among dietary generalists as among dietary specialists. Yet competition between insects that are dietary generalists is infrequently studied. We tested for evidence of competitive interactions between two common, temporally separated, generalist insects: the western tent caterpillar (Malacosoma californicum), which feeds early in the season, and the fall webworm (Hyphantria cunea), which feeds later in the season. Both species frequently use a common host plant species (chokecherry) as a preferred host at our field sites. We tested the relative strength of bottom-up effects resulting from competitive interactions between these two generalists with laboratory-rearing trials at the relevant time of year for each insect. We recorded three common fitness measures (development time, pupal mass, and survival) for caterpillars reared on chokecherry with no damage from either of our focal species, with tent caterpillar damage, and with fall webworm damage. To test the strength of top-down pressures on fall webworm larval fitness and any potential interactions with bottom-up effects, we reared larvae in the field either exposed to or protected from predators on host plants that either did or did not have tent caterpillars feeding on them earlier in the season. We found evidence of bottom-up fitness effects on tent caterpillars and top-down and bottom-up fitness effects on fall webworms confirming that tent caterpillars and fall webworms compete indirectly. Tent caterpillars had lower pupal mass when reared on leaves from shrubs damaged by fall webworms. Fall webworms had lower pupal mass and longer development time when reared on leaves from shrubs damaged by tent caterpillars. In field trials, fall webworms reared on shrubs damaged by tent caterpillars had a lower survival and pupal mass. We show evidence of indirect competition in temporally separated generalists through leaf quality (bottom-up effects) and natural enemies (top-down effects).

Tuber wenchuanense, a holarctic truffle with a wide range of host plants and description of its ectomycorrhiza with spruce

Tuber wenchuanense ascomata (Ascomycota, Pezizales), a species originally described from Sichuan (China), were found in the Tatra Mountains in southern Poland. The purpose of this work was to (i) report and assess the first case of the holarctic natural distribution of a Tuber species, (ii) amend the original description of the species, (iii) summarize data on its host plants and (iv) describe its ectomycorrhiza. Specimens of Tuber wenchuanense from the Tatra Mountains were studied morphologically and molecularly. The ectomycorrhiza of this truffle with Picea abies was described for the first time. The distribution of T. wenchuanense, which is reconstructed based on sequences deposited in the publicly available nucleotide sequence databases, makes it the first holarctic Tuber species and the one with the northernmost habitat. In fact, its habitat is confined mainly to mountain coniferous forests and alpine and arctic tundra; although, according to known observations, the fruiting bodies of T. wenchuanense can be produced only under conifers. Based on the sequences of the internal transcribed spacer, this species appears to have low genetic variability over the entire distribution range. The phylogenetic tree showed that some of the unidentified phylotypes from the Rufum clade found by other researchers belong to T. wenchuanense. The ecological implications of these findings are discussed.

The mechanism of genome replication and transcription in bunyaviruses.

Bunyaviruses are negative sense, single-strand RNA viruses that infect a wide range of vertebrate, invertebrate and plant hosts. WHO lists three bunyavirus diseases as priority diseases requiring urgent development of medical countermeasures highlighting their high epidemic potential. While the viral large (L) protein containing the RNA-dependent RNA polymerase is a key enzyme in the viral replication cycle and therefore a suitable drug target, our knowledge on the structure and activities of this multifunctional protein has, until recently, been very limited. However, in the last few years, facilitated by the technical advances in the field of cryogenic electron microscopy, many structures of bunyavirus L proteins have been solved. These structures significantly enhance our mechanistic understanding of bunyavirus genome replication and transcription processes and highlight differences and commonalities between the L proteins of different bunyavirus families. Here, we provide a review of our current understanding of genome replication and transcription in bunyaviruses with a focus on the viral L protein. Further, we compare within bunyaviruses and with the related influenza virus polymerase complex and highlight open questions.

Global transcriptome and targeted metabolite analyses of roots reveal different defence mechanisms against Ralstonia solanacearum infection in two resistant potato cultivars.

Ralstonia solanacearum (Rs), the causal agent of bacterial wilt disease in an unusually wide range of host plants, including potato (Solanum tuberosum), is one of the most destructive phytopathogens that seriously reduces crop yields worldwide. Identification of defence mechanisms underlying bacterial wilt resistance is a prerequisite for biotechnological approaches to resistance breeding. Resistance to Rs has been reported only in a few potato landraces and cultivars. Our in vitro inoculation bioassays confirmed that the cultivars 'Calalo Gaspar' (CG) and 'Cruza 148' (CR) are resistant to Rs infection. Comparative transcriptome analyses of CG and CR roots, as well as of the roots of an Rs-susceptible cultivar, 'Désirée' (DES), were carried out two days after Rs infection, in parallel with their respective noninfected controls. In CR and DES, the upregulation of chitin interactions and cell wall-related genes was detected. The phenylpropanoid biosynthesis and glutathione metabolism pathways were induced only in CR, as confirmed by high levels of lignification over the whole stele in CR roots six days after Rs infection. At the same time, Rs infection greatly increased the concentrations of chlorogenic acid and quercetin derivatives in CG roots as it was detected using ultra-performance liquid chromatography - tandem mass spectrometry. Characteristic increases in the expression of MAP kinase signalling pathway genes and in the concentrations of jasmonic, salicylic, abscisic and indoleacetic acid were measured in DES roots. These results indicate different Rs defence mechanisms in the two resistant potato cultivars and a different response to Rs infection in the susceptible cultivar.

Natural Recombination among Type I Restriction-Modification Systems Creates Diverse Genomic Methylation Patterns among Xylella fastidiosa Strains.

Xylella fastidiosa is an important bacterial plant pathogen causing high-consequence diseases in agricultural crops around the world. Although as a species X. fastidiosa can infect many host plants, there is significant variability between strains regarding virulence on specific host plant species and other traits. Natural competence and horizontal gene transfer are believed to occur frequently in X. fastidiosa and likely influence the evolution of this pathogen. However, some X. fastidiosa strains are difficult to manipulate genetically using standard transformation techniques. Several type I restriction-modification (R-M) systems are encoded in the X. fastidiosa genome, which may influence horizontal gene transfer and recombination. Type I R-M systems themselves may undergo recombination, exchanging target recognition domains (TRDs) between specificity subunits (hsdS) to generate novel alleles with new target specificities. In this study, several conserved type I R-M systems were compared across 129 X. fastidiosa genome assemblies representing all known subspecies and 32 sequence types. Forty-four unique TRDs were identified among 50 hsdS alleles, which are arrayed in 31 allele profiles that are generally conserved within a monophyletic cluster of strains. Inactivating mutations were identified in type I R-M systems of specific strains, showing heterogeneity in the complements of functional type I R-M systems across X. fastidiosa. Genomic DNA methylation patterns were characterized in 20 X. fastidiosa strains and associated with type I R-M system allele profiles. Overall, these data suggest hsdS genes recombine among Xylella strains and/or unknown donors, and the resulting TRD reassortment establishes differential epigenetic modifications across Xylella lineages. IMPORTANCE Economic impacts on agricultural production due to X. fastidiosa have been severe in the Americas, Europe, and parts of Asia. Despite a long history of research on this pathogen, certain fundamental questions regarding the biology, pathogenicity, and evolution of X. fastidiosa have still not been answered. Wide-scale whole-genome sequencing has begun to provide more insight into X. fastidiosa genetic diversity and horizontal gene transfer, but the mechanics of genomic recombination in natural settings and the extent to which this directly influences bacterial phenotypes such as plant host range are not well understood. Genome methylation is an important factor in horizontal gene transfer and bacterial recombination that has not been comprehensively studied in X. fastidiosa. This study characterizes methylation associated with type I restriction-modification systems across a wide range of X. fastidiosa strains and lays the groundwork for a better understanding of X. fastidiosa biology and evolution through epigenetics.

Comparative Genomic Analysis of 31 Phytophthora Genomes Reveals Genome Plasticity and Horizontal Gene Transfer.

Phytophthora species are oomycete plant pathogens that cause great economic and ecological impacts. The Phytophthora genus includes over 180 known species, infecting a wide range of plant hosts, including crops, trees, and ornamentals. We sequenced the genomes of 31 individual Phytophthora species and 24 individual transcriptomes to study genetic relationships across the genus. De novo genome assemblies revealed variation in genome sizes, numbers of predicted genes, and in repetitive element content across the Phytophthora genus. A genus-wide comparison evaluated orthologous groups of genes. Predicted effector gene counts varied across Phytophthora species by effector family, genome size, and plant host range. Predicted numbers of apoplastic effectors increased as the host range of Phytophthora species increased. Predicted numbers of cytoplasmic effectors also increased with host range but leveled off or decreased in Phytophthora species that have enormous host ranges. With extensive sequencing across the Phytophthora genus, we now have the genomic resources to evaluate horizontal gene transfer events across the oomycetes. Using a machine-learning approach to identify horizontally transferred genes with bacterial or fungal origin, we identified 44 candidates over 36 Phytophthora species genomes. Phylogenetic reconstruction indicates that the transfers of most of these 44 candidates happened in parallel to major advances in the evolution of the oomycetes and Phytophthora spp. We conclude that the 31 genomes presented here are essential for investigating genus-wide genomic associations in genus Phytophthora. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Diversity of Sporocadaceae (pestalotioid fungi) from Rosa in China.

Rosa (Rosaceae) is an important ornamental and medicinal plant genus worldwide, with several species being cultivated in China. Members of Sporocadaceae (pestalotioid fungi) are globally distributed and include endophytes, saprobes but also plant pathogens, infecting a broad range of host plants on which they can cause important plant diseases. Although several Sporocadaceae species were recorded to inhabit Rosa spp., the taxa occurring on Rosa remain largely unresolved. In this study, a total of 295 diseased samples were collected from branches, fruits, leaves and spines of eight Rosa species (R. chinensis, R. helenae, R. laevigata, R. multiflora, R. omeiensis, R. rugosa, R. spinosissima and R. xanthina) in Gansu, Henan, Hunan, Qinghai, Shaanxi Provinces and the Ningxia Autonomous Region of China. Subsequently 126 strains were obtained and identified based on comparisons of DNA sequence data. Based on these results 15 species residing in six genera of Sporocadaceae were delineated, including four known species (Pestalotiopsis chamaeropis, Pes. rhodomyrtus, Sporocadus sorbi and Spo. trimorphus) and 11 new species described here as Monochaetia rosarum, Neopestalotiopsis concentrica, N. subepidermalis, Pestalotiopsis tumida, Seimatosporium centrale, Seim. gracile, Seim. nonappendiculatum, Seim. parvum, Seiridium rosae, Sporocadus brevis, and Spo. spiniger. This study also represents the first report of Pes. chamaeropis, Pes. rhodomyrtus and Spo. sorbi on Rosa. The overall data revealed that Pestalotiopsis was the most prevalent genus, followed by Seimatosporium, while Pes. chamaeropis and Pes. rhodomyrtus were the two most prevalent species. Analysis of Sporocadaceae abundance on Rosa species and plant organs revealed that spines of R. chinensis had the highest species diversity. Citation: Peng C, Crous PW, Jiang N, et al. 2022. Diversity of Sporocadaceae (pestalotioid fungi) from Rosa in China. Persoonia 49: 201-260. https://doi.org/10.3767/persoonia.2022.49.07.

First record of Opsiphanes cassina fabricii (Lepidoptera: Nymphalidae) feeding on Christmas palm Adonidia merrillii (Arecales: Arecaceae)

The “Split-banded Owlet-Butterfly” Opsiphanes cassina Felder & Felder (Lepidoptera: Nymphalidae) comprises 12 subspecies occurring throughout Central America and in northern and western South America. In this work, O. cassina fabricii (Boisduval) was identified feeding on “Christmas palm” Adonidia merrillii (Becc.) Becc. (Arecales: Arecaceae) in the gardens of a housing unit in the state of Tabasco, Mexico. Identification was based on wing characters and genitalia morphology of males and females. This is the first record of O. cassina fabricii feeding on A. merrillii leaflets, which broadens the host plant range of this insect. In addition, some biological aspects and the damage caused by this species to “Christmas palm” are discussed.

Phosphate Solubilizing Bacteria (PSB) Isolation from Tomato Rhizospheres at Koka District, Ethiopia

Phosphorous is an essential macronutrient for plant growth and development. Most of the soil is deficient in plant available phosphorous and due to economic limitations majority of Ethiopian farmers applied inadequate fertilizers. It is essential to stabilize a mechanism to access P for plants with an efficient, cheap, and eco-friendly approach for enhanced crop growth and production. The main objective of this study was to screen efficient phosphate solubilizing bacteria from tomato rhizosphere soil. Using halo zone formation on PVK agar medium, more than 400 PSB isolates were isolated from 13 rhizosphere soil samples. By evaluating SI, texture in the culture-re-culturing process, liquid medium pH change efficiency and growth rate, upmost three promising PSB isolates (K-1-29, K-10-27, and K-10-41) were selected. Incubation of the isolates in PVK broth for five days showed significant pH reduction. For instance, isolate K-10-41 showed significant pH change (4.02) which indicates the organic acid production. Isolation and evaluation of efficient phosphate solubilizing bacteria maintain soil fertility, promote plant growth, induce plant response to pathogens, reduce agrochemical consumption and promote sustainable agriculture. Therefore, these selected PSB isolates need further detailed study for taxonomic identification, plant growth promotion, host range, and phytopathogen response. Local isolation improves environmental adaptation and indigenous competition.

CopE and TLR6 RNAi-mediated tomato resistance to western flower thrips

The western flower thrips (WFT; Frankliniella occidentalis) is a mesophyll cell feeder that damages many crops. Management of WFT is complex due to factors such as high fecundity, short reproduction time, ability to feed on a broad range of host plants, and broad pesticide resistance. These challenges have driven research into developing alternative pest control approaches for WFT. This study analyzed the feasibility of a biological control-based strategy to manage WFT using RNA interference (RNAi)-mediated silencing of WTF endogenous genes. For the delivery of RNAi, we developed transgenic tomato lines expressing double-stranded RNA (dsRNA) of coatomer protein subunit epsilon (CopE) and Toll-like receptor 6 (TLR6) from WFT. These genes are involved in critical biological processes of WFT, and their dsRNA can be lethal to these insects when ingested orally. Adult WFT that fed on the transgenic dsRNA-expressing tomato flower stalk showed increased mortality compared with insects that fed on wild-type samples. In addition, WFT that fed on TLR6 and CopE transgenic tomato RNAi lines showed reduced levels of endogenous CopE and TLR6 transcripts, suggesting that their mortality was likely due to RNAi-mediated silencing of these genes. Thus, our findings demonstrate that transgenic tomato plants expressing dsRNA of TLR6 and CopE can be lethal to F. occidentalis, suggesting that these genes may be deployed to control insecticide-resistant WFT.