Alternative Host Research Articles

Comparative genomics identifies genetic markers linked to structural variations that differentiate Puccinia graminis tritici and secalis formae speciales

AbstractStem rust is a serious disease of many gramineous plants including small grain staples such as wheat, barley, rye and triticale. Separate formae speciales (ff. spp.) of the causal fungus, Puccinia graminis, predominantly infect certain host plant genera. However, despite these taxonomic subdivisions, many P. graminis ff. spp. are genetically too similar to distinguish using existing genetic markers. For those infecting cereals, this is particularly challenging for P. graminis f. sp. tritici (Pgt) and P. graminis f. sp. secalis (Pgs). Herein we harnessed newly available genomic data for 39 Pgt and Pgs isolates and identified four regions of structural variation that were used to design four simple PCR‐based assays to distinguish the aforementioned formae speciales. These genomic regions display large presence/absence variation between Pgt and Pgs isolates, and yet a high degree of sequence conservation within shared neighbouring regions, facilitating primer design. We also confirmed lack of amplification in host plant genera analysed, which included assessment of the shared alternate host of Pgt and Pgs, Berberis vulgaris. Accurate classification of P. graminis ff. spp. infections on B. vulgaris is exceptionally valuable to rapidly define plants harbouring P. graminis inoculum when adjacent to cereal crops. Finally, we demonstrated utility of these four genetic markers to correctly distinguish a genetically diverse array of Pgt and Pgs isolates. This strategy could now be readily applied to other pathogens of interest, which will be of increasing value as genomic resources continue to rapidly expand for many key biotic threats to agricultural productivity.

Phytopathogenic Curtobacterium flaccumfaciens Strains Circulating on Leguminous Plants, Alternative Hosts and Weeds in Russia.

Many bacterial plant pathogens have a broad host range important for their life cycle. Alternate hosts from plant families other than the main (primary) host support the survival and dissemination of the pathogen population even in absence of main host plants. Metabolic peculiarities of main and alternative host plants can affect genetic diversity within and between the pathogen populations isolated from those plants. Strains of Gram-positive bacterium Curtobacterium flaccumfaciens were identified as being causal agents of bacterial spot and wilt diseases on leguminous plants, and other crop and weed plants, collected in different regions of Russia. Their biochemical properties and susceptibility to copper compounds have been found to be relatively uniform. According to conventional PCR assays, all of the isolates studied were categorised as pathovar Curtobacterim flaccumfaciens pv. flaccumfaciens, a pathogen of legumes. However, the strains demonstrated a substantial diversity in terms of virulence on several tested host plants and different phylogenetic relationships were revealed by BOX-PCR and alanine synthase gene (alaS) sequencing.

First report of Puccinia recondita rust on native jewelweed (Impatiens capensis) in Pennsylvania.

Jewelweed (Impatiens spp., Balsaminaceae) is a common native annual plant within Pennsylvania wetland ecosystems, many of which are under threat from invasive non-native plants, and is an important wetland indicator plant (code FACW; facultative wetland). In May 2014, rust disease symptoms on native jewelweed (Impatiens capensis Meerb.) were observed within a small (0.1 ha) wet area in York County, southeastern Pennsylvania (39.9080648oN, -77.2472024oW). Rust symptoms were noted on most jewelweed plants within the wet area. Foliar symptoms included chlorosis and premature defoliation; infected stems were distorted. Infected leaves and stems contained orange, erumpent aecia with white fragmented peridia (Fig. 1). Symptomatic leaves and stem sections were collected from five infected plants within one small (5 X 5 m) plot in the center of the wet area and taken to the laboratory for microscopic observations and morphological measurements. Mean aecia diameter was 299.2 ± 55.0 µm (n = 60). Aeciospores were single-celled, orange, and generally globose (Fig. 2) with a mean diameter of 24.4 ± 1.4 µm, (n = 60). Disease symptomology and aecia morphology were consistent with Puccinia recondita Dietel & Holw. DNA extraction (from infected stem material), polymerase chain reactions, and DNA sequencing of the 28S region of the nuclear ribosomal DNA repeat was conducted following protocols in Aime (2006) and Aime et al. (2018). The sequence shares 99.34% identity (903 / 909 bp) with P. recondita (BPI 910319) collected in California (KY798399). A voucher specimen has been deposited in the Arthur Fungarium at Purdue University (PUR N24229) with corresponding 28S sequence (GenBank accession OR648406). P. recondita has been reported on native I. capensis in Indiana (Koslow and Clay 2010) and North Carolina (Grand 1985), but not in Pennsylvania to the best of our knowledge (Farr and Rossman 2022). If this rust disease becomes severe on native jewelweeds in Pennsylvania, it may adversely affect our ability to accurately classify native wetlands in the state. In addition, P. recondita is a heteroecious rust that is a major pathogen of grain crops of economic importance (i.e., wheat, barley, oats), which are grown in southeastern Pennsylvania near the infested area. Further research is warranted to understand if native, annual jewelweed can serve as a secondary or alternate host to cause rust disease in major cereal crops.

First Report of Dickeya dadantii Causing Soft Rot in Cariru in Brazil.

Cariru (Talinum fruticosum) is a non-conventional food plant and a source of vitamins A, B2, B5, and C, calcium, phosphorus, and iron. It is an important crop for producers of the Amazon region and it is used as a leafy green vegetable, similar to spinach, as well as for medicinal purposes. It is cultivated by producers in the states of Pará and Amazonas (Amorim et al. 2014). In February 2020, in gardens of approximately 1.0 and 0.18 ha in the municipality of Ananindeua (01° 34' 12" S - 48° 38' 11" W), Pará, Brazil, we observed approximately 10% of the plants exhibited soft rot symptoms, bacterial oozing, and stem pith disintegration. From cariru infected leaves, the bacteria were selectively isolated using healthy pepper fruit, as described by Moraes et al. (2017). Two strain (UFRADD17 and UFRADD18) were obtained and both showed white, small, "broken glass" colonies on CPG (peptone-casamino acid-glucose) medium when observed in a stereoscope under oblique lighting. Pathogenicity tests were performed on 20-day-old cariru seedlings by depositing 10 ul of the bacterial suspension (106 CFU/ml) onto a wound made on the leaf blade with an entomological pin. After inoculation, seedlings were incubated in a greenhouse for 48 h at 30 ± 2°C and 90 ± 2% RH. Plants treated similarly with sterile distilled water were used as a negative control. Symptoms of soft rot were observed between 12 and 24 h after inoculation. Seedlings used as negative control remained symptomless. Forty-eight hours after inoculation, we reisolated the pathogen and performed rep-PCR (REP, ERIC, and BOX-PCR) analyses (Gama et al. 2018) with the strains used for inoculation and those reisolated from the pathogenicity test to confirm the identity of the strains and to fulfill Koch's postulates. The two re-isolated strains showed the same REP, ERIC, and BOX-PCR profiles as the strains used for inoculation. In addition, there were no differences between the rep-PCR profiles of the isolates UFRADD17 and UFRADD18. These isolates were Gram-negative, grew at 37°C, and were positive for maceration in pepper fruit and potato tubers. Molecular identification of the isolate UFRADD18 was performed from sequencing fragments from the 16S rDNA region and dnaX, fusA, gyrA, and mdH housekeeping genes as previously described (Van der Wolf et al. 2014; Ma et al. 2007). Sequences were deposited in Genbank under accessions OP142347, OP191704, OP191705, OP191706, and OP191707. Blastn analysis showed 96.15% identity with the 16S rDNA region of accession KY231142.1 (400/416 bp), 99.5% identity with dnaX of accession KC844490.1 (396/398 bp), 99.86% identity with fusA of accession CP023467.1 (714/715 bp), 99.74% identity with gyrA of accession KC844598 (387/388 bp), and 99.10% identity with mdH of accession GQ891979.1 (563/560 bp) from the type strain of Dickeya dadantii. A phylogenetic analysis performed by Bayesian inference with the dnaX, fusA, gyrA, and mdH genes grouped the isolate UFRADD18 along with NCPPB898T, with a 1.00 posterior probability. To our knowledge, this is the first report of D. dadantii causing soft rot in cariru in the Brazilian territory. In addition, this report increases understanding of the host range of this bacterium, which is important for adopting management strategies based on the control of alternative hosts.

Rust HUBB: DNA barcode-based identification of Pucciniales

Rust fungi (Pucciniales, Basidiomycota) are a species-rich (ca. 8000 species), globally distributed order of obligate plant pathogens. Rust species are host-specific, and as a group they cause disease on many of our most economically and/or ecologically significant plants. As such, the ability to accurately and rapidly identify these fungi is of particular interest to mycologists, botanists, agricultural scientists, farmers, quarantine officials, and associated stakeholders. However, the complexities of the rust life cycle, which may include production of up to five different spore types and alternation between two unrelated host species, have made standard identifications, especially of less-documented spore states or alternate hosts, extremely difficult. The Arthur Fungarium (PUR) at Purdue University is home to one of the most comprehensive collections of rust fungi in the world. Using material vouchered in PUR supplemented with fresh collections we generated DNA barcodes of the 28S ribosomal repeat from > 3700 rust fungal specimens. Barcoded material spans 120 genera and > 1100 species, most represented by several replicate sequences. Barcodes and associated metadata are hosted in a publicly accessible, BLAST searchable database called Rust HUBB (Herbarium-based Universal Barcode Blast) and will be continuously updated.

Feeding on lactic acid bacteria isolated from food extends the lifespan of Caenorhabditis elegans.

Lactic acid bacteria (LAB) contribute to human health, and LAB functionality has been studied using Caenorhabditis elegans as an alternative host. However, many studies have focused on the efficacy of a single strain of LAB, and few reports have compared various LAB strains. In this study, we examined the effects of 15 strains of LAB isolated from vegetables, meat, and fermented foods on nematode longevity and healthy lifespan. To reduce the frequency of laborious survival observations, we performed a lifespan assay on agar plates containing 2'-deoxy-5-fluorouridine (FUdR), which inhibits egg hatching and prevents generation mixing. Four beneficial strains showed significant lifespan extension and increased spontaneous nematode mobility, regardless of treatment with or without FUdR and the frequency of survival observation. These results suggested increased longevity and an extended healthy lifespan, confirming the reliability of our method. The four strains are expected to show anti-ageing effects besides longevity and have effects on age-related degenerative diseases. Our labor-saving method can be used as an alternative to conventional methods and enable simultaneous screening of multiple strains. Future research could explore factors contributing to lifespan regulation by comparing and verifying differential strain effects on lifespan.

First Report of Melon Chlorotic Spot Virus in Cultivated Sorrel (Rumex acetosa) in Belgium

In 2020, symptoms of putative viral origin were observed on 7% of tomatoes in an organic vegetable farm in Belgium (deformed uneven ripened fruits, vein clearing, mosaic and purple leaves, stunted plants). The leaves of twenty symptomatic plants were collected, pooled and screened for viruses using high throughput sequencing technologies (HTS) on Illumina NextSeq500 following a virion-associated nucleic acid (VANA) protocol (Temple et al., 2021, Be_SL1). In total, 3,665,498 reads (PE150) were generated. Bioinformatic analyses (denovo assembly, tblastx search on NCBI and mapping) using Geneious Prime® 2020.1.2 revealed the presence of three viruses known to infect tomatoes: Physostegia chlorotic mottle virus (PhCMoV), 547,142 reads map on NC_055466, potato virus Y (PVY), 4056 reads map on MW595184, and melon chlorotic spot virus (MeCSV), 55 reads mapped to six out of the eight different MeCSV segments (NC_040448-55). Tomato plants have already been artificially inoculated by MeCSV (Lecoq et al., 2019) but this detection (confirmed by independent RT-PCR on the pooled sample) is the first one in natural condition on farm. The high prevalence of symptoms triggered the research of alternative perennial hosts that can serve as a reservoir during inter-cropping season. One plant of Rumex acetosa showing vein clearing (CT-122) was collected in the same greenhouse the year after. Total RNA was extracted, followed by ribodepletion, and Illumina HTS using the protocol described in Temple et al., (2021) for Be_GP1. In total, 4,549,721 PE150 reads were obtained and bioinformatic analyses confirmed the presence of MeCSV (8,816 reads mapped on eight RNA segments NC_040448-55 with an average 96,52% coverage of the reference sequences, supplementary table 1) and suggested the presence of an unclassified partitivirus. Consensus sequences were extracted for each segment of MeCSV (OQ818038-45) and showed between 83% and 87% of nucleotide identity with the reference sequences NC_040448-55. RNA1 segment was used to design MeCSV-specific RT-PCR primers for detection (MeCSV-125F 5’-TTTAAGGCCAGATCCAGAGGTTC-3’/ MeCSV-498R 5’-TGGATGTGACAACCTGGTAGTAC-3’). Thereafter, in July 2022, 42 R. acetosa plants were collected in the same greenhouse. Among them, seven plants showed vein clearing, two showed yellowing with necrosis, two exhibited yellowing and vein clearing (Supplementary figure 1), and one showed mosaic. The 42 plants were subjected to RNA extraction and RT-PCR for MeCSV (Supplementary figure 2) and PhCMoV detection. MeCSV was detected in 13 plants (two asymptomatic plants and all the symptomatic plants except the one exhibiting mosaic where PhCMoV was detected). PhCMoV was also detected in three plants with vein clearing, one with yellowing and one of the two asymptomatic plants infected by MeCSV. Our results report the first detection of MeCSV in R. acetosa and the first detection of MeCSV in Belgium. In addition, according to the hierarchical approach for assessing causal relationships in plant virology (Fox et al., 2020), a preliminary association was observed between symptoms and MeCSV detection [6% prevalence on asymptomatic plants and 92% prevalence on diseased plants (from which seven symptomatic samples were not co-infected by PhCMoV)]. Symptom causality should be further investigated but this results are important for disease management because they suggested that cultivated perennial R. acetosa may serve as a reservoir for two emergent plant viruses (PhCMoV and MeCSV) (Lecoq et al., 2019, Temple et al., 2021).

Parasitizing efficiency of Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) on Galleria mellonella (Linnaeus) (Lepidoptera: Pyralidae) larva and pupa

BackgroundThis study evaluated the parasitizing efficiency of Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) on the Galleria mellonella (Linnaeus) (Lepidoptera: Pyralidae) larvae and pupae. The sixth instar larvae and 48 h. old pupae were individually exposed for 24 h. to 15 newly emerged mated females of T. howardi. Following the emergence of parasitoids, observations were recorded on the percentage of parasitized and emergent pupae and larvae, life cycle duration, progeny, male and female emergence, sex ratio, longevity of male and female and adult per mg weight.ResultsIn both pupal and larval, parasitization and emergence were 100%. The pupa produced 438.56 progenies, with 394.76 females and 43.2 males and a sex ratio of 0.89. In larvae, 311.93 progenies emerged, with 259.83 females and 53.0 males and a sex ratio of 0.83. The T. howardi life cycle duration was 17.66 days in pupae and 20.13 days in larvae. Longevity of female and male progeny that emerged from pupae and larvae was 15.83, 13.40, and 10.40, 8.76 days respectively. The overall progeny production in pupae and larvae was 2.75 and 1.60 individuals per mg body weight, respectively.ConclusionsThe highest parasitism as well as biological and reproductive development of T. howardi in G. mellonella pupae and larvae suggests that this host could be employed as an alternate host for mass multiplication.

A multi-scale approach to study palm-weevils in a tropical agroecosystem

Abstract Context The recent phytosanitary crisis caused by the stem borer weevils Dynamis borassi and Rhynchophorus palmarum in peach palms (Bactris gasipaes) seriously affects the economy of rural families in Colombia. To understand the possible ecological mechanisms favoring the pest, the weevil-palm system needs to be studied from a multi-scale perspective. Objectives We evaluated the combined effects of agricultural management, landscape, topography, soil, and climate variables on infestation levels of peach palm caused by the weevils D. borassi and R. palmarum in the Colombian southwest to understand underlying ecological drivers of the current phytosanitary crisis. Methods The palm infestation levels (response variable) and local agronomic practices were recorded in 32 sites across Colombia's Pacific, Andes, and Amazon natural regions. For each peach palm crop, landscape variables were estimated from classified Sentinel-2 images, soil variables were extracted from the Soil Grids 250 m database, and climate variables were extracted from the CHIRPS and CHIRTS databases. Explanatory variables were analyzed using Generalized Linear Models and Partial Least Squares-Generalized Linear Models. Results Landscape variables, specifically the number and shape of non-forest patches, had a greater influence on peach palm infestation levels than other environmental variables, possibly related to the decrease in the density of Oenocarpus batatua, the natural palm host for D. borassi, leading it to switch to the peach palm. Conclusions A multi-scale approach of the weevil-palm interaction enabled us to identify an ecological mechanism that has not been proposed before. Our recommendation for families depending on peach palm is to design palm management with a landscape perspective that considers the conservation of alternative hosts for the weevils in agroforestal plots.

Insight into the host-specificity of a native and a newly introduced parasitoid of Tuta absoluta and prospect for biological control

New strategies are urgently needed to control Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), one of the most destructive pests of tomato crops. Originating from South America, it is spreading rapidly and has evolved resistance to most common insecticides making it highly challenging to control. Regarding biological control, the parasitoid Necremnus tutae Ribes & Bernardo (Hymenoptera: Eulophidae) is widely present around the Mediterranean basin and has adapted to the invader playing a substantial role in its control. In addition, the neotropical parasitoid Dolichogenidea gelechiidivoris Marsh (Hymenoptera: Braconidae) has established accidentally following its host in Spain and Algeria and a classical biological control program using this species is ongoing in Sub-Saharan Africa. Understanding the trophic connections between D.gelechiidivoris, N.tutae, the targeted host T.absoluta and potential non-target hosts is essential to assess their value as augmentative or classical biological control agents and to promote their establishment in conservation biocontrol. We conducted host-specificity tests in the laboratory using four European leafminer species to evaluate the specificity of these two parasitoids to T.absoluta. We then assessed their affinity for T.absoluta by exposing sentinel plants with the alternative host Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) inside and around greenhouses and measuring each parasitoid species' field parasitism rate. Our results show that of the four non-target species tested in the laboratory, N.tutae attacked three, while D.gelechiidivoris attacked only P. operculella. In the greenhouse, N.tutae did not prefer P.operculella or T.absoluta, whereas D.gelechiidivoris preferred the latter. The mean parasitism rate of T.absoluta over the three-month monitoring period in the greenhouses reached 27% for N.tutae and 35% for D.gelechiidivoris. We discuss the importance of host affinity for understanding potential non-target effects and the value a natural enemy can have as biological control.

Using Vibrio natriegens for High-Yield Production of Challenging Expression Targets and for Protein Perdeuteration.

Production of soluble proteins is essential for structure/function studies; however, this usually requires milligram amounts of protein, which can be difficult to obtain with traditional expression systems. Recently, the Gram-negative bacterium Vibrio natriegens emerged as a novel and alternative host platform for production of proteins in high yields. Here, we used a commercial strain derived from V. natriegens (Vmax X2) to produce soluble bacterial and fungal proteins in milligram scale, which we struggled to achieve in Escherichia coli. These proteins include the cholera toxin (CT) and N-acetyl glucosamine-binding protein A (GbpA) from Vibrio cholerae, the heat-labile enterotoxin (LT) from E. coli and the fungal nematotoxin CCTX2 from Coprinopsis cinerea. CT, GbpA, and LT are secreted by the Type II secretion system in their natural hosts. When these three proteins were produced in Vmax, they were also secreted and could be recovered from the growth media. This simplified the downstream purification procedure and resulted in considerably higher protein yields compared to production in E. coli (6- to 26-fold increase). We also tested Vmax for protein perdeuteration using deuterated minimal media with deuterium oxide as solvent and achieved a 3-fold increase in yield compared to the equivalent protocol in E. coli. This is good news, since isotopic labeling is expensive and often ineffective but represents a necessary prerequisite for some structural biology techniques. Thus, Vmax represents a promising host for production of challenging expression targets and for protein perdeuteration in amounts suitable for structural biology studies.

Bazı yabancı otların Plum pox virüs T ile ilgili çalışmalarda indikatör bitki olarak kullanım potansiyelinin belirlenmesi

Determination of the potential of some weeds to be used as an indicator plant in studies on Plum pox virus-T
 
 ABSTRACT 
 The plum pox virus (PPV) is the cause of sharka, the most destructive viral disease of Prunus species. A unique strain of PPV has so far been identified in Turkey and called as PPV-Turkey (PPV-T). Since viruses are obligate parasitic organisms, they cannot be cultured in artificial nutrient media. Weeds play a significant role in virus ecology and epidemiology as alternate hosts of plant viruses and as food plants for virus vectors. In this study, the potential of some weeds (such as Chenopodium album, Amaranthus retroflexus and Convolvulus arvensis) are indicators plants in experimental studies on PPV-T was investigated. C. album, A. retroflexus plants were inoculated by dusting three leaf on each 3-week-old plant. For each experiment, a homogeneous group of 10 plants grown singly in pots was inoculated PPV-T. Mock- and non-inoculated plants were used as negative controls. Inoculated plants were monitored dayl for symptom development. Following appearance of symptoms on PPV-T inoculated leaves tested by reverse transcription-polymerase chain reaction (RT-PCR). The results obtained from the indicator test showed that when mechanically inoculated of the two out of three plants tested species, C. album (6 out of 10 plants) and A. retroflexus (10 plants) reacted with infection. Initially, this indicator reacted with local symptoms, and later symptoms of systemic infection occurred.
 
 Keywords: Plum pox virus, PPV-Turkey, Herbaceous hosts, 
 Indicator plant

In Vitro Sensitivity Test of Fusarium Species from Weeds and Non-Gramineous Plants to Triazole Fungicides.

Fusarium species are common plant pathogens that cause serious crop losses worldwide. Fusarium spp. colonize not only the main host plants, crops, but also alternative hosts. The effectiveness of fungicide use in disease management ranges from very successful to possibly promoting the growth of the pathogen. Triazole fungicides are widely used to control these pathogens due to their broad-spectrum activity and systemic nature. This paper reviews the sensitivity of 40 Fusarium strains isolated from weeds, non-gramineous plants, and spring wheat to metconazole, prothioconazole, and tebuconazole. The effect of fungicides was determined by the percentage inhibition of F. graminearum, F. culmorum, F. sporotrichioides, and F. avenaceum fungal mycelial growth. The 50% effective concentration (EC50) values of all isolates on metconazole were lower than 2.9 mg L-1, prothioconazole EC50 ranged from 0.12 to 23.6 mg L-1, and tebuconazole ranged from 0.09 to 15.6 mg L-1. At 0.00025-0.025 mg L-1, the fungicides were ineffective, except for the growth of the F. avenaceum species. It was observed that isolates from weeds were more sensitive to low concentrations of fungicide than isolates from crop plants. In general, information is scarce regarding the comparison of fungicide resistance in Fusarium isolates from weed and crop plants, making this study an additional contribution to the existing knowledge base.

Komagataella phaffii as a Platform for Heterologous Expression of Enzymes Used for Industry.

In the 1980s, Escherichia coli was the preferred host for heterologous protein expression owing to its capacity for rapid growth in complex media; well-studied genetics; rapid and direct transformation with foreign DNA; and easily scalable fermentation. Despite the relative ease of use of E. coli for achieving the high expression of many recombinant proteins, for some proteins, e.g., membrane proteins or proteins of eukaryotic origin, this approach can be rather ineffective. Another microorganism long-used and popular as an expression system is baker's yeast, Saccharomyces cerevisiae. In spite of a number of obvious advantages of these yeasts as host cells, there are some limitations on their use as expression systems, for example, inefficient secretion, misfolding, hyperglycosylation, and aberrant proteolytic processing of proteins. Over the past decade, nontraditional yeast species have been adapted to the role of alternative hosts for the production of recombinant proteins, e.g., Komagataella phaffii, Yarrowia lipolytica, and Schizosaccharomyces pombe. These yeast species' several physiological characteristics (that are different from those of S. cerevisiae), such as faster growth on cheap carbon sources and higher secretion capacity, make them practical alternative hosts for biotechnological purposes. Currently, the K. phaffii-based expression system is one of the most popular for the production of heterologous proteins. Along with the low secretion of endogenous proteins, K. phaffii efficiently produces and secretes heterologous proteins in high yields, thereby reducing the cost of purifying the latter. This review will discuss practical approaches and technological solutions for the efficient expression of recombinant proteins in K. phaffii, mainly based on the example of enzymes used for the feed industry.

A test of trade-offs in dispersal and reproduction within and between a sister species pair of specialist insect herbivores.

Understanding the drivers of trade-offs among traits is vital for comprehending the evolution and maintenance of trait variation. Theoretical frameworks propose that evolutionary mechanisms governing trade-offs frequently exhibit a scale-dependent nature. However, empirical tests of whether trade-offs exhibited across various biological scales (i.e. individuals, populations, species, genera, etc.) remains scarce. In this study, we explore trade-off between dispersal and reproductive effort among sympatric sister species of wasps in the genus Belonocnema (Hymenoptera: Cynipini: Cynipidae) that form galls on live oaks: B. fossoria, which specializes on Quercus geminata, and B. treatae, which specializes on Q. virginiana. Specifically, our results suggest that B. fossoria has evolved reduced flight capability and smaller wings, but a larger abdomen and greater total reproductive effort than B. treatae, which has larger wings and is a stronger flier, but has a smaller abdomen and reduced total reproductive effort. These traits and the relationships among them remain unchanged when B. fossoria and B. treatae are transplanted and reared onto the alternative host plant, suggesting that trait divergence is genetically based as opposed to being a plastic response to the different rearing environments. However, when looking within species, we found no evidence of intraspecific trade-offs between wing length and reproductive traits within either B. fossoria or B. treatae. Overall, our results indicate that observed trade-offs in life history traits between the two gall former species are likely a result of independent adaptations in response to different environments as opposed to the amplified expression of within species intrinsic tradeoffs.

Plant–herbivore–natural enemy trophic webs in date palm agro-ecosystems

Understanding the composition and dynamics of ecological communities is challenging because of the large number of organisms present and their numerous interactions. Among agricultural systems, intercropping considerably increases the complexity of communities compared to monocultures and alternative host plants can influence insect pest damage. Using literature records, we construct and analyse connectance trophic webs of date palm (Phoenix dactylifera) agro-ecosystems, including and excluding intercrops. Estimates of connectance (community complexity) are relatively low and little affected by consideration of intercrops. Plant–herbivore overlap is relatively high, suggesting that herbivores are typically not specialists. Herbivore–natural enemy overlap is greater when intercrops are considered, suggesting that diffuse apparent competition regulates pest populations. We pay particular attention to how trophic web structure might affect Batrachedra amydraula (Lesser date moth), an important economic pest. Records indicate it having 15 species of natural enemies and sharing 9 of these with other herbivores; these may maintain populations of natural enemies when the moth is seasonally rare, contributing to pest suppression. The estimated potential for apparent competition between the lesser date moth and other herbivores is higher when intercrops are considered. The consequent expectation of less severe infestations in plantations that are intercropped compared to monocultures matches empirically derived reports. Further, comparing results obtained from the literature on one country (Oman) and from 15 Middle Eastern countries, we find that community metric estimates are relatively little affected by the geographical scale considered. Overall, our results suggest that literature-based trophic web construction can provide an efficient and robust alternative, or in addition, to direct empirical methodologies and that the presence of intercrops will contribute to major pest suppression via indirect apparent competition.

Development of a Standardized Soybean Cyst Nematode Screening Assay in Pennycress and Identification of Resistant Germplasm.

The prospect of incorporating pennycress as an oilseed cover crop in the Midwest's corn-soybean rotation system has drawn researcher and farmer attention. The inclusion of pennycress will be beneficial as it provides an excellent soil cover to reduce soil erosion and nutrient leaching while serving as an additional source for oilseed production and income. However, pennycress is an alternative host for soybean cyst nematode (SCN), which is a major biological threat to soybean that needs to be addressed for sustainable pennycress adoption into our current production systems. To develop a standardized SCN resistance screening strategy in pennycress, we tested and optimized five parameters: (i) germination stimulants, (ii) inoculation timing, (iii) inoculation rate, (iv) experimental incubation time, and (v) susceptible checks. The standardized SCN resistance screening protocol includes the following: (i) treating pennycress seeds with gibberellic acid for 24 h, (ii) transplanting seedlings 12 to 15 days after initiating germination and inoculating 10 to 12 days after transplantation, (iii) inoculating at a rate of 1,500 eggs/100 cc soil (1,500 eggs per plant), (iv) processing roots at 30 days after inoculation, and (v) using susceptible pennycress accession Ames 32869 to calculate the female index. The standardized protocol was used to quantify the response of a diverse set of pennycress accessions for response against SCN HG type 1.2.5.7 and HG type 7. While there were no highly resistant pennycress lines identified, 15 were rated as moderately resistant to HG type 1.2.5.7, and eight were rated moderately resistant to HG type 7. The resistant lines identified in this study could be utilized to develop SCN-resistant pennycress cultivars. The study also opens a new avenue for research to understand SCN-pennycress interactions through molecular and genomic studies. This knowledge could aid in the successful inclusion of pennycress as a beneficial cover/oilseed crop in the United States Midwest.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Spodoptera cosmioides (Lepidoptera: Noctuidae) as an alternative host for mass rearing the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae)

Abstract Different alternative hosts can reduce or even avoid pre-imaginal conditioning of parasitoids in mass production programs. Spodoptera cosmioides (Walker) (Lepidoptera: Noctuidae) may be an alternative host for mass rearing the parasitoid Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae). The objective of this study was to evaluate the parasitism, emergence, egg-to-adult period, progeny size, sex ratio, and consumption of host tissue per individual of P. elaeisis produced using S. cosmioides pupae in the laboratory. Newly formed S. cosmioides pupae were weighed, individualized in glass tubes and each one was exposed to six newly emerged P. elaeisis females during 48 h. These pupae were transferred to plastic pots until the emergence of P. elaeisis adults. Palmistichus elaeisis parasitized and emerged from 100.0 % and 87.5 % of the S. cosmioides pupae, respectively. The egg-to-adult period of P. elaeisis was 24.28 ± 0.18 days, with 109 ± 2 individuals emerging per host pupae. Mass consumption of the host was 2.56 ± 0.01 mg per parasitoid emerged. This is the first report of P. elaeisis parasitizing and developing in S. cosmioides pupae. The ease of rearing S. cosmioides with an artificial diet, and the high parasitism, emergence, and progeny size of P. elaeisis support the suitability of this alternative host to mass-rearing this parasitoid.

Recombinant protein production in Pseudoalteromonas haloplanktis TAC125 biofilm

Biofilms have great potential for producing valuable products, and recent research has been performed on biofilms for the production of compounds with biotechnological and industrial relevance. However, the production of recombinant proteins using this system is still limited. The recombinant protein production in microbial hosts is a well-established technology and a variety of expression systems are available. Nevertheless, the production of some recombinant proteins can result in proteolyzed, insoluble, and non-functional forms, therefore it is necessary to start the exploration of non-conventional production systems that, in the future, could be helpful to produce some “difficult” proteins. Non-conventional production systems can be based on the use of alternative hosts and/or on non-conventional ways to grow recombinant cells. In this paper, the use of the Antarctic marine bacterium Pseudoalteromonas haloplanktis TAC125 grown in biofilm conditions was explored to produce two fluorescent proteins, GFP and mScarlet. The best conditions for the production were identified by working on media composition, and induction conditions, and by building a new expression vector suitable for the biofilm conditions. Results reported demonstrated that the optimized system for the recombinant protein production in biofilm, although it takes longer than planktonic production, has the same potentiality as the classical planktonic approach with additional advantages since it needs a lower concentration of the carbon sources and doesn't require antibiotic addition. Moreover, in the case of mScarlet, the production in biofilm outperforms the planktonic system in terms of a better quality of the recombinant product.

Survey for Alternate Weed Hosts of Rice Root-Knot Nematode, Meloidogyne graminicola Associated with Rice Crops in Haryana, India

Rice root-knot nematode, Meloidogyne graminicola is one of the most serious nematode pest associated with rice throughout the world. With other species of root-knot nematode, M. graminicola can also infect wide range of weed flora which is commonly grown in or near the rice field. To study the alternate weed hosts of M. graminicola a survey was conducted in the major rice growing blocks of Fatehabad and Sirsa districts of Haryana during Kharif season 2022. A total of 726 samples were collected from rice fields, both from transplanted (TR) and direct seeded rice (DSR) from Phoolan, Bharpur, Ratta Khera, and Jandwala Sotter villages of Fatehabad and Bahauddin and Sikanderpur, Dhottar, Ding and Chopta villages of Sirsa. Out of which 353 samples were found free from nematode infestation while 373 samples (209 from DSR and 164 from TR)were found infested. The juveniles and galls were recorded ranging from 4-190 on the roots of different weed plants. Hence, it is concluded from the present investigation, that nematodes favor more DSR and its weed flora than TR for infection and survival.