Visible Disease Symptoms Research Articles

Rapid Detection of Viral, Bacterial, Fungal, and Oomycete Pathogens on Tomatoes with Microneedles, LAMP on a Microfluidic Chip, and Smartphone Device.

Rapid detection of plant diseases before they escalate can improve disease control. Our team has developed rapid nucleic acid extraction methods with microneedles and combined these with loop-mediated amplification (LAMP) assays for pathogen detection in the field. In this work, we developed LAMP assays for early blight (Alternaria linariae, A. alternata, and A. solani) and bacterial spot of tomato (Xanthomonas perforans) and validated these LAMP assays and two previously developed LAMP assays for tomato spotted wilt virus and late blight. Tomato plants were inoculated, and disease severity was measured. Extractions were performed using microneedles, and LAMP assays were run in tubes (with hydroxynaphthol blue) on a heat block or on a newly designed microfluidic slide chip on a heat block or a slide heater. Fluorescence on the microfluidic chip slides was visualized using EvaGreen and photographed on a smartphone. Plants inoculated with X. perforans or tomato spotted wilt virus tested positive prior to visible disease symptoms, whereas Phytophthora infestans and A. linariae were detected at the time of visual disease symptoms. LAMP assays were more sensitive than PCR, and the limit of detection was 1 pg of DNA for both A. linariae and X. perforans. The LAMP assay designed for early blight detected all three species of Alternaria that infect tomato and is thus an Alternaria spp. assay. This study demonstrates the utility of rapid microneedle extraction followed by LAMP on a microfluidic chip for rapid diagnosis of four important tomato pathogens.

Molecular identification and pathogenicity of endophytic fungi from corn ears

Endophytic fungi are widely known as fungi that infect internal tissues of host plants for all or part of their life cycles, without causing visible symptoms of disease. The present study was carried out to identify and investigate the pathogenicity of endophytic fungi residing in husks, silks, and kernels of corn. Endophytic fungi were isolated from surface-sterilised silks, kernels, and husks of healthy corn plants and identified using sequencing of multiple markers comprising TEF-1α, β-tubulin, calmodulin, ITS, LSU, and ACT. A total of 56 isolates of endophytic fungi belonging to 17 species, namely Fusarium pseudocircinatum (n = 8), F. verticillioides (n = 2), F. andiyazi (n = 4), F. sacchari (n = 1), F. mangiferae (n = 1), F. fujikuroi (n = 1), F. proliferatum (n = 3), F. incarnatum (n = 2), Penicillium oxalicum (n = 2), P. polonicum (n = 2), P. citrinum (n = 11), Aspergillus flavus (n = 10), A. tubingensis (n = 1), Cladosporium tenuissimum (n = 3), Aureobasidium pullulans (n = 3), Curvularia lunata (n = 1), and Epicoccum sorghinum (n = 1) were identified. Pathogenicity test showed that all endophytic fungi induced varying severities of disease symptoms on corn plants such as leaf chlorosis and necrosis, stem malformation, wilt, and stunted growth with F. verticillioides being the most virulent. The study revealed that corn tissues harbour diverse genera of endophytic fungi that can infect corn plants and may cause harmful effects to the host plants.

Molecular Identification of Ascomycetes from American Cranberry (Vaccinium macrocarpon Aiton) Grown in Plantation in Poland

The American cranberry is a perennial North American fruit plant that is grown successfully on commercial plantations in Poland. The purpose of this study was to recognize filamentous fungi that colonize roots, leaves, and fruits without visible disease symptoms. Pure fungal cultures were isolated from disinfected plant fragments in agar media and identified by sequencing common taxonomic DNA markers such as the ITS region, the TEF-1α, or RPB2 genes. Of the 141 isolates studied, 59% were identified as closely related to soil saprotrophs. They were classified primarily as showing the greatest similarity to type strains of Trichoderma amoenum, Trichoderma dorothopsis, Paraphaeosphaeria sporulosa, and Penicillium murcianum. Additionally, isolates that are most similar to strains of Penicillium crustosum, Aspergillus flavus, and Aspergillus versicolor that produced mycotoxins were detected. The fungi identified as closest to Alternaria geophila, Alternaria senecionicola, Paraphoma radicina, Pestalotiopsis unicolor, Pestalotiopsis scoparia, and Neopestalotiopsis spp., whose hosts are plants other than American cranberry, represented 33.81% of the isolates tested. Only 7.2% of the isolates corresponded to the species of Physalospora vaccinia, Diaporthe vaccinii, and Diaporthe eres, known cranberry pathogens. The results of this study can be used to identify latent plant infection and potential disease risks.

Standard methods to estimate strength parameters, flight activity, comb construction, and fitness of Apis mellifera colonies 2.0

This paper describes methods for estimating honey bee (Apis mellifera) colony strength by which mean population measures of adult bees and brood are obtained. Additionally, secondary measures, such as the quantity of stored honey and pollen, brood pattern, flight activity, comb construction, and the expression of visible disease or parasite symptoms are addressed. There are generally two contexts in which an investigator wishes to measure colony strength: (1) at the beginning of a study as part of manipulations to produce uniform colonies and reduce experimental error, and (2) as a response variable during or at the end of an experiment. Moreover, there are two general modes for measuring colony strength: (1) an objective mode that uses quantitative measures, and (2) a subjective mode that relies on visual estimates by one or more observers. Other parameters that do not directly measure colony strength are described because they give important indicators of colony state. These parameters include flight activity at the hive entrance, comb construction, and two proxy measures of colony fitness: production of queen cells and drone brood.

Comprehensive insights into sorghum (Sorghum bicolor) defense mechanisms unveiled: Plant growth-promoting rhizobacteria in combating Burkholderia-induced bacterial leaf stripe disease

Sorghum, a vital cereal crop with significant importance in traditional human health systems, faces severe challenges from biotic stresses. This study aimed to assess the morpho-physiological variations and plant growth promoting rhizobacteria (PGPR)-induced defense mechanisms in sorghum against Burkholderia sp. infection, a well-known cause of bacterial leaf stripe disease. Also, the alterations in the leaf protein band profile of sorghum exposed to Burkholderia infection were assessed via 2-D gel electrophoresis wherein the disappearance of protein bands in diseased leaf tissues was recorded. The selected PGPR, A. chroococcum Beijerinck 1901 (MCC 2351), B. megaterium (MCC 2336), and P. fluorescens (NAIMCC B-00,340), secreted hydrogen cyanide and ammonia, and produced lytic enzymes, cellulase and amylase. When tested in-planta, Burkholderia sp., applied as a foliar spray, more profoundly impacted the growth as compared to seed coat application, resulting in significant reductions in root dry biomass, whole plant length, and total chlorophyll content by 93.9, 73.4 and 53.8 %, respectively, compared to disease-free control. Visible symptoms of bacterial leaf stripe disease like brown discoloration and necrotic lesions were observed in infected sorghum plants. Furthermore, the level of phytochemicals, proline, and malondialdehyde and antioxidants, CAT and SOD, in foliage declined significantly by 46.4, 70.2, 20.7, and 16.9 %, respectively, following inoculation with Bacillus applied as a seed coat. Additionally, Burkholderia-infected plants exhibited cellular damage, mainly in leaf tissues, as revealed by SEM and CLSM. Interestingly, the PGPR inoculation substantially enhanced the measured growth parameters of sorghum while reducing the levels of phytochemicals and antioxidants. These findings suggest that A. chroococcum, B. megaterium, and P. fluorescens, possessing biocontrol activity, can be employed as a profitable, environment and pocket-friendly approach for managing plant diseases and promoting the production of sorghum under biotic stress, thereby sufficing the human food demands.

Influence of the endophytic fungus <i>Metarhizium robertsii</i> on the growth and development of forage beans siberian varieties

The results of studying the influence of the endophytic fungus Metarhizium robertsii on the growth and development of fodder beans of the Sibirskie variety are presented. Endophytes are ubiquitous, diverse microorganisms that live in healthy host tissues without causing visible disease symptoms. The studies were conducted in 2020–2022. Pre-sowing treatment of broad bean seeds (Vicia faba L.) with the entomopathogenic fungus M. robertsii, followed by cultivation in field conditions, contributed to the acceleration of growth processes, the formation of greater biological mass and increased yield. The effectiveness of the entomopathogenic fungus M. robertsii was assessed in a field experiment on leached chernozem in the forest-steppe zone of Western Siberia. M. robertsii on broad beans significantly increased grain yield by 10–15 % depending on year conditions in 2020 and 2022. (Mann-Whitney test, p = 0.036715 and 0.012186, respectively), plant height - by 6–16 cm (Mann-Whitney test, p = 0.010023), foliage, and weight of 1000 grains. A significant increase in active nodules on the roots of broad bean plants treated with M. robertsii was established. The results indicate that treating bean seeds with the entomopathogenic fungus M. robertsii before sowing can increase crop yield and stimulate growth processes. In the future, this technique can be used in agricultural practice on other legumes. This work is the first study of the influence of entomopathogenic fungi on broad beans when grown in the continental climate of Western Siberia.

Cat Disease Detection Expert System Application Using WML on Mobile Phone

This research aims to find out how to implement the forward chaining method in an expert system. This research used observation methods, questionnaires, literature studies, and interviews conducted with experts, namely veterinarians. This interview was conducted in the form of an unstructured interview. The researcher used a PC (personal computer) as the hardware. The software used in this research is Notepad++ 6.1.6. The operating system that the author uses in research is Windows XP SP2. The research results show that using this expert system helps detect disease in animals by helping users consult by answering a series of questions based on visible disease symptoms, which in turn will lead to a series of answers leading to a particular disease. In the solutions section, you can find first aid measures and follow-up actions that pet owners are expected to take to help the animal recover. Adding knowledge, documentation, and development to this expert system can be done via the mobile phone available on the admin page, so there is no need to overhaul the existing system; just insert, delete, and update. Development can be carried out by people with authority to add symptoms, diseases, and solutions to diseases.

Evidence of Xylella fastidiosa Infection and Associated Thermal Signatures in Southern Highbush Blueberry (Vaccinium corymbosum Interspecific Hybrids).

Xylella fastidiosa, a gram-negative bacterium vectored to plants via feeding of infected insects, causes a number of notorious plant diseases throughout the world, such as Pierce's disease (grapes), olive quick decline syndrome, and coffee leaf scorch. Detection of Xf in infected plants can be challenging because the early foliar disease symptoms are subtle and may be attributed to multiple minor physiological stresses and/or borderline nutrient deficiencies. Furthermore, Xf may reside within an infected plant for one or more growing seasons before traditional visible diagnostic disease symptoms emerge. Any method that can identify infection during the latent period or pre-diagnostic disease progress state could substantially improve the outcome of disease control interventions. Because Xf locally and gradually impairs water movement through infected plant stems and leaves over time, infected plants may not be able to effectively dissipate heat through transpiration-assisted cooling, and this heat signature may be an important pre-diagnostic disease trait. Here, we report on the association between thermal imaging, the early stages of Xf infection, and disease development in blueberry plants, and discuss the benefits and limitations of using thermal imaging to detect bacterial leaf scorch of blueberries.

Pathological Features and Genetic Polymorphism Analysis of Tomato Spotted Wilt Virus in Infected Tomato Fruit.

An in-house tomato inbred line, YNAU335, was planted in a greenhouse in spring from 2014 to 2017, and showed immunity to tomato spotted wilt virus (TSWV). YNAU335 was infected with TSWV in the spring from 2018 to 2020, and disease was observed on the leaves, sepals, and fruits. In 2021 and 2022, YNAU335 was planted in spring in the same greenhouse, which was suspected of being infected with TSWV, and visible disease symptoms were observed on the fruits. Transmission electron microscopy, deep sequencing of small RNAs, and molecular mutation diagnosis were used to analyze the pathological features and genetic polymorphism of TSWV infecting tomato fruit. Typical TSWV virions were observed in the infected fruits, but not leaves from YNAU335 grown between 2021 and 2022, and cross-infection was very rarely observed. The number of mitochondria and chloroplasts increased, but the damage to the mitochondria was greater than that seen in the chloroplasts. Small RNA deep sequencing revealed the presence of multiple viral species in TSWV-infected and non-infected tomato samples grown between 2014-2022. Many virus species, including TSWV, which accounted for the largest proportion, were detected in the TSWV-infected tomato leaves and fruit. However, a variety of viruses other than TSWV were also detected in the non-infected tissues. The amino acids of TSWV nucleocapsid proteins (NPs) and movement proteins (MPs) from diseased fruits of YNAU335 picked in 2021-2022 were found to be very diverse. Compared with previously identified NPs and MPs from TSWV isolates, those found in this study could be divided into three types: non-resistance-breaking, resistance-breaking, and other isolates. The number of positive clones and a comparison with previously identified amino acid mutations suggested that mutation F at AA118 of the MP (GenBank OL310707) is likely the key to breaking the resistance to TSWV, and this mutation developed only in the infected fruit of YNAU335 grown in 2021 and 2022.

A pathogenesis-related protein 1 of Cucurbita moschata responds to powdery mildew infection.

Pumpkin (Cucurbita moschata Duch.) productivity is severely hindered by powdery mildew (PM) worldwide. The causative agent of pumpkin PM is Podosphaera xanthii, a biotrophic fungus. Pathogenesis-related protein 1 (PR1) homolog was previously identified from transcriptomic analysis of a PM-resistant pumpkin. Here, we investigated the effects of CmPR1 gene from pumpkin for resistance to PM. Subcellular localization assay revealed that CmPR1 is a cytoplasmic protein in plants. The expression of CmPR1 gene was strongly induced by P. xanthii inoculation at 48h and exogenous ethylene (ET), jasmonic acid (JA) and NaCl treatments, but repressed by H2O2 and salicylic acid (SA) treatments. Visual disease symptoms, histological observations of fungal growth and host cell death, and accumulation of H2O2 in transgenic tobacco plants indicated that CmPR1 overexpression significantly enhanced the resistance to Golovinomyces cichoracearum compared to wild type plants during PM pathogens infection, possibly due to inducing cell death and H2O2 accumulation near infected sites. The expression of PR1a was significantly induced in transgenic tobacco plants in response to G. cichoracearum, suggesting that CmPR1 overexpression positively modulates the resistance to PM via the SA signaling pathway. These findings indicate that CmPR1 is a defense response gene in C. moschata and can be exploited to develop disease-resistant crop varieties.

Best Practices for Monitoring Visual Symptoms of Grapevine Red Blotch Disease in Black-Fruited Winegrape Cultivars

Best Practices for Monitoring Visual Symptoms of Grapevine Red Blotch Disease in Black-Fruited Winegrape Cultivars

Root Growth and Defense Response of Seedlings against Fusarium oxysporum in Sand Culture and In Vitro—A Comparison of Two Screening Approaches for Asparagus Cultivars

Two rapid asparagus (Asparagus officinalis L.) screening methods, in sand culture and in vitro, were tested to evaluate the response of young seedlings against F. oxysporum f. sp. asparagi (isolate Foa1). Root morphological parameters were evaluated and correlated with the symptomatology and expression of the defense-related genes at 5 and 7 dpi. In sand cultivation, the Foa1-inoculated cultivars showed no visible disease symptoms on their roots until 7 dpi. Two-factorial ANOVA statistics found no significant interaction between the cultivars and treatments for most root parameters but some differences between the cultivars. The in vitro Foa1-inoculated cultivars showed high susceptibility according to their symptomatology and differed greatly in the length of the primary root at 5 dpi. In some cultivars, the primary root length and root surface area were higher upon Foa1 inoculation. The expression changes were very different among the cultivars, with significant induction of PR1, POX, and PAL at 5 dpi in all cultivars in vitro but only in two cultivars in sand cultivation. The in vitro screening method, although more artificial, seemed to be more reliable than sand cultivation since the fungus was able to develop well in the culture medium. In sand-filled pots, the fungus may have been hindered in its development, even though a considerable higher amount of Foa1 was inoculated. In addition, the fungal growth was easily trackable in tubes, while in sand cultivation, the results were only visible after pulling the seedlings out of the pots 12 dpi.

Evidence of a Natural Hybrid Oomycete Isolated from Ornamental Nursery Stock

The oomycete genus Phytophthora includes many plant pathogens important in agricultural and environmental systems. Natural interspecific hybridization has been reported several times in Phytophthora, and although the fundamental processes of interspecific hybridization and the consequences of subsequent ecological distribution are poorly understood, reports suggest some hybrids can infect a broader host range and display enhanced virulence compared to the putative parental species. During a survey carried out at the University of Aberdeen in 2014–2015, of oomycetes present in ornamental plants purchased via the internet, a batch of oomycete isolates remained unidentified, showing, in some isolates, features generally related to hybridization. The aim of this study was to determine whether hybridization events had occurred between endemic and introduced oomycetes, probably/possibly facilitated through the international plant trade. The list of isolates examined included a putative hybrid closely related to Phytophthora cryptogea. The putative hybrid isolate was further characterized, and pathogenicity were tests carried out on Eucalyptus globulus, using an isolate of P. cryptogea as a positive control. Cloning of ITS, COXI and β-tubulin genes resulted in different sequence versions of the putative hybrid isolate; after mapping and a polymorphism position comparison, it was concluded that the studied isolate contained genetic information from P. cryptogea, P. erythroseptica, P. kelmanii, P. sansomeana and Phytopythium chamaehyphon. A PCR-RFLP assay, a NEBcutter analysis and flow cytometry analysis (genomes ranged between 0.168 to 0.269 pg/2C) added further evidence of the hybrid nature of this isolate. The putative hybrid presented complex growing patterns ranging from rosaceous to chrysanthemum-like and had an optimum growth temperature of 25 °C. Although the putative hybrid produced visible symptoms of disease on E. globulus seedlings, assessment of the relative susceptibility of E. globulus to P. cryptogea and the putative hybrid indicated that P. cryptogea was significantly more virulent than the putative hybrid, based on mortality, disease severity and foliar symptoms.

Identification and Characterization of a Novel Quanzhou Mulberry Virus from Mulberry (Morus alba).

In this study, we discovered a new virus named Quanzhou mulberry virus (QMV), which was identified from the leaves of an ancient mulberry tree. This tree is over 1300 years old and is located at Fujian Kaiyuan Temple, a renowned cultural heritage site in China. We obtained the complete genome sequence of QMV using RNA sequencing followed by rapid amplification of complementary DNA ends (RACE). The QMV genome is 9256 nucleotides (nt) long and encodes five open reading frames (ORFs). Its virion was made of icosahedral particles. Phylogenetic analysis suggests that it belongs to the unclassified Riboviria. An infectious clone for QMV was generated and agroinfiltrated into Nicotiana benthamiana and mulberry, resulting in no visible disease symptoms. However, systemic movement of the virus was only observed in mulberry seedlings, suggesting that it has a host-specific pattern of movement. Our findings provide a valuable reference for further studies on QMV and related viruses, contributing to the understanding of viral evolution and biodiversity in mulberry.

Genetically engineered bacterial strains constructed as a whole-cell biosensor for specific volatiles identification of infected potato tubers with a soft rot disease

The potato (Solanum tuberosum) is the most globally popular non-cereal crop. During postharvest storage, the potato is susceptible to various diseases. Specifically, the symptoms of tuber soft rot can be identified visibly only after irreversible damage has already been caused. The existing technologies are not optimized for the identification of hidden diseases, thus, an early and sensitive diagnostic tool is needed. An attractive early-stage technology is based on monitoring the volatile organic compounds (VOCs) as indicators of pathogen presence. In this study, genetically engineered bacterial strains were constructed as a whole-cell biosensor for specific volatiles identification of infected potato tubers with soft rot disease. Identified volatiles were chosen (i.e., 1-Octanol, 2-Phenylethyl Alcohol, and 1-Octen-3-ol) as model toxicants and used for the identification of the responsive promoters in the host cell Escherichia coli through RNA sequencing and bioinformatic analysis. Furthermore, the promoter activity was verified by a fusion to luciferase-harboring plasmid. The bioluminescent bacterial cells monitor the changes in the VOC profile, and a signal change is then generated, reflecting the infection status of the potatoes. The efficacy of the recombinant bacteria to monitor potato soft rot disease was investigated in solution, surrounding air near pure volatiles, and around potato tubers contaminated by Pectobacterium. The results demonstrated that the new strains were sensitive to the presence of these VOCs, each to a different extent and in a different environment (solution or surrounding air). All of them except oxyR could detect differences between infected and uninfected potato tubers. The preferred bioreporter to detect Pectobacterium infection in whole potato tubers is dnaK. This strain responds to all tested volatiles in the liquid and gaseous states and has shown the highest response differences as a reaction to the infection presence in the whole potato tubers. Bacterial monitoring of the volatile profile results in identifying specific signatures that will allow quick and accurate detection of the presence of pathogens in stored crops, prior to visible disease symptoms.

First report of Colletotrichum circinans causing anthracnose on Polygonatum sibiricum in Liaoning Province, China.

Polygonatum sibiricum (Huangjing, Siberian Solomon's seal) is a perennial plant of the family Asparagaceae. Used in traditional Chinese medicine in northeast China, P. sibiricum has become widely cultivated in recent years. During late June and early July 2021, leaf fleck symptoms were observed on P. sibiricum at a plantation in Liaoning Province, a major Huangjing production region in China. According to our survey, the incidence of the disease was over 50%. Symptoms initially appeared on infected leaves as necrotic spots, which increased in size and extended to circular or elliptical, pale to light brown lesions with well-defined dark brown margin. To identify the pathogen, leaves showing typical symptoms of infected plants were collected. Leaf samples were excised from the junction of both healthy and symptomatic tissues as 5 mm diameter pieces. Tissue samples were surface-sterilized with successive washes of 75% ethanol (25 sec), 0.1% mercuric chloride solution (1.5 min), three rinses with sterile distilled water, and then left to air dry (Zhongda 2007). Finally, the tissue pieces were plated on potato dextrose agar (PDA), and incubated at 25°C for 5 days in the dark. Six individual colonies with similar cultural morphology were isolated by transferring mycelium plugs from the margins of colonies to new PDA dishes and were incubated under the same conditions. Two representative isolates (S3-2, S5-3) were used for morphological and molecular identifications. Colonies on PDA were initially whitish, then turned dark grey with age, and were covered with aerial mycelium. On the reverse side, colonies were initially whitish and turned grey to dark black with age. Conidia were hyaline, aseptate, little curved and apex acute, and with sizes of 17.5 to 22.5×3 to 4 µm. Setae were dark brown, subuliform with 2 to 4 septate, 110 to 160 µm long. The morphological and cultural characteristics are consistent with the description of Colletotrichum circinans (Damm, et al. 2009). For molecular identification, genomic DNA was extracted from mycelia of the representative fungal strains. Internal transcribed spacers (ITS) region, actin (ACT), chitin synthase 1(CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and betatubulin (TUB2) genes amplified by using specific primers and PCR conditions described in (Ji Ma, et al. 2020). The resulting sequences were submitted to the GenBank. BlastN revealed that ITS(OM019299, OM937757), ACT(OM455393, OM937756), CHS1(OM455391, OM937754), GAPDH(OM455392, OM937755), Tub2(OM455394, OM937758) were identified as C. circinans. The ITS, ACT, CHS1, GAPDH, Tub2 sequences of the strains and other Colletotrichum species were multiple aligned using ClustalW implemented in MEGA5.1 and used for phylogenetic tree construction by Maximum likelihood method, with bootstrap value of 1000 replicates (Tamura et al. 2011). Monilochaetes infuscans (CBS:869.96) was used as an outgroup. The analysis indicated that the strains grouped with C. circinans with good bootstrap support, further supporting the morphological and single-gene molecular identifications. Pathogenicity was demonstrated by in vivo inoculation of leaves of three-month-old healthy P. sibiricum seedlings. Before inoculation, all the leaves of P. sibiricum were surface-sterilized with 75% ethanol and washed with sterile water twice (Jin Chen, et al. 2021). Each plant was inoculated by placing three mycelial plugs (5mm; taken from an actively-growing colony of the isolates) on a single healthy leaf, and the second leaf of each plant was inoculated by a sterile PDA plug as a control. After inoculation, plants were placed in an incubator held at a constant 25℃ and relative humidity (>80%) with a 16h/8h day/night cycle. The experiment was repeated three times. The brown spots were observed after 6 days on inoculated leaves, while no visible disease symptoms were observed on control leaves. The acervulus and conidia were visible on the dorsal of diseased leaves 11-13 days after inoculation. The same pathogen was reisolated and confirmed as C.circinans by morphological comparison, fulfilling Koch's postulates. These results illustrated that C.circinans was responsible for the anthracnose disease of P. sibiricum. To our knowledge, this is the first report of C. circinans causing anthracnose on P. sibiricum in Liaoning Province, and an effective control method should be adopted to reduce losses.

Visible skin disease symptoms of another person reduce automatic imitation of their hand movements.

Imitation is an important mechanism for social interaction and learning, and humans tend to imitate others automatically. While imitating others is often useful, it can backfire when imitation is incongruent with one's goals. For example, in forced-choice reaction time tasks, this tendency results in a reliable slowing of reactions if the observed and self-initiated actions are incompatible (compatibility effect). While imitation is commonly explained as a social phenomenon, previous results on the compatibility effect's dependence on social cues are inconsistent. However, in many previous studies, the associated social cues were easy to ignore by the participants. To make the social modifier more salient, the current study manipulated emotionally relevant aspects of the model hand itself in an imitation inhibition task by using models displaying skin disease symptoms which we expected to elicit (1) perceptions of dissimilarity and (2) disgust in participants. As predicted, participants' (n = 63) reaction times were influenced more by the incompatible actions of the symptom-free than the symptomatic model hand. However, both levels of self-reported disgust toward and self-other overlap with symptomatic hands were low and did not account for the observed effect on automatic imitation. Our findings show that automatic imitation depends on social factors if these are an integral part of the model and processed quickly, presumably due to their affective salience or the salience of the self-other distinction. Whether this effect is driven by emotional reactions to the model remains an open question.

The presenting visual symptoms of optic chiasmal disease.

Recognising optic chiasmal disease early is important in order to avoid irreversible visual loss and the potential risk of mortality for patients. Yet, there is frequently a delay in the initial diagnosis. Whilst the signs of optic chiasmal disease, particularly the perimetric findings, are well documented in the recent literature, the symptoms have been less well reported. Whilst some patients with optic chiasmal disease will be asymptomatic, many will complain of visual symptoms including symptomatic field defects, problems with central vision, difficulty with near tasks, binocular visual disturbances, colour vision disturbances, photophobia, phosphenes, glare, and rarely, oscillopsia and visual hallucinations. Others may have headache or the severe and sudden visual symptoms associated with pituitary apoplexy. The visual symptoms may be vague or non-specific, even when there are significant bitemporal visual field defects. We aim in this review to describe the presenting visual symptoms of optic chiasmal disease, and to illustrate these with selected qualitative descriptions from the literature. Our hope is that this will aid clinicians in eliciting a careful history of the sometimes subtle symptoms that may be present.

Unravelling pine response to Fusarium circinatum through Raman spectroscopy

AbstractPine Pitch Canker (PPC), caused by the fungus Fusarium circinatum, is associated to significant economic and ecological losses worldwide. The effectiveness of PPC monitoring, early detection in nurseries and plantations, and the identification of resistant plant material relies on the development of objective, non‐destructive, and cost‐effective tools. This study analyzed the potential of employing Raman Spectroscopy (RS) for the early detection of biochemical changes associated with PPC in Pinus spp. with different susceptibilities to F. circinatum (highly susceptible Pinus radiata vs relatively resistant Pinus pinea), while unveiling possible mechanisms of action on these pathosystems. Our results indicate lignin as a key constitutive component of pine resistance against PPC and thus the potential of using this technology for the selection of PPC resistant trees. Moreover, we demonstrate the power of RS‐based approaches for the rapid detection of the disease in susceptible species. Early spectral variations were found in P. radiata upon inoculation with F. circinatum from 3 days post‐inoculation (dpi) onwards, whereas changes in histological analysis, relative internal stem necrosis measurements, and visual disease symptoms were only visible at 6, 8, and 9 dpi, respectively. These spectral changes have been associated to cell wall degradation and induction of phenolic compounds synthesis upon infection in P. radiata. Altogether, we believe that RS is an innovative promising tool able to reduce disease detection time in pine species and providing an appealing alternative for the development of new and eco‐friendly disease control measures.

Sugarcane Genotypes with Contrasting Biological Nitrogen Fixation Efficiencies Differentially Modulate Nitrogen Metabolism, Auxin Signaling, and Microorganism Perception Pathways.

Sugarcane is an economically important crop that is used for the production of fuel ethanol. Diazotrophic bacteria have been isolated from sugarcane tissues, without causing visible plant anatomical changes or disease symptoms. These bacteria can be beneficial to the plant by promoting root growth and an increase in plant yield. Different rates of Biological Nitrogen Fixation (BNF) were observed in different genotypes. The aim of this work was to conduct a comprehensive molecular and physiological analysis of two model genotypes for contrasting BNF efficiency in order to unravel plant genes that are differentially regulated during a natural association with diazotrophic bacteria. A next-generation sequencing of RNA samples from the genotypes SP70-1143 (high-BNF) and Chunee (low-BNF) was performed. A differential transcriptome analysis showed that several pathways were differentially regulated among the two BNF-contrasting genotypes, including nitrogen metabolism, hormone regulation and bacteria recognition. Physiological analyses, such as nitrogenase and GS activity quantification, bacterial colonization, auxin response and root architecture evaluation, supported the transcriptome expression analyses. The differences observed between the genotypes may explain, at least in part, the differences in BNF contributions. Some of the identified genes might be involved in key regulatory processes for a beneficial association and could be further used as tools for obtaining more efficient BNF genotypes.