Transcriptome Analysis of “Candidatus Liberibacter solanacearum” in Its Psyllid Vector, Bactericera cockerelli

"Candidatus Liberibacter solanacearum” (Lso) is an emergent pathogen of carrots in Europe and solanaceous plants in North and Central America and New Zealand. This bacterium is closely related to other pathogenic Candidatus Liberibacter spp., all vectored by psyllids. In order to understand the molecular interaction of this pathogen and its psyllid vector, Bactericera cockerelli, Illumina sequencing of psyllid harboring Lso was performed to determine if this approach could be used to assess the bacterial transcriptome in this association. Prior to sequencing, psyllid RNA was purified and insect and bacterial rRNA were removed. Mapping of reads to Lso genome revealed that over 92% of the bacterial genes were expressed in the vector, and that the COG categories Translation and Post-translational modification, protein turnover, chaperone functions were the most expressed functional categories. Expression levels of selected Lso genes were confirmed by RT-qPCR. The transcriptomic analysis also helped correct Lso genome annotation by identifying the expression of genes that were not predicted in the genome sequencing effort.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund

Identification and Expression Analysis of Aquaporins in the Potato Psyllid, Bactericera cockerelli

Aquaporin (AQPs) proteins transport water and uncharged low molecular-weight solutes across biological membranes. Six to 8 AQP genes have been identified in many insect species, but presently only three aquaporins have been characterized in phloem feeding insects. The objective of this study was to identify candidate AQPs in the potato psyllid, Bactericera cockerelli. Herein, we identified four candidate aquaporin cDNAs in B. cockerelli transcriptome. Phylogenetic analysis showed that candidate BcAQP2-like had high similarity to PRIP aquaporins; while candidates BcAQP4-like, BcAQP5-like and BcAQP9-like clustered within clade B. In particular, candidates BcAQP4-like and BcAQP5-like clustered with functionally validated insect aquaglyceroporin proteins. Expression analyses using RT-qPCR showed that all candidates were expressed in all life stages and tissues. Candidates BcAQP4-like and BcAQP5-like were highly expressed in bacteriocytes, while BcAQP9-like appeared to be expressed at high levels in whole body but not in the assayed tissues. This study is the first global attempt to identify putative aquaporins in a phloem feeding insect.The open access fee for this work was funded through the Texas A&M University Open Access to Knowledge (OAK) Fund

Genomic resources for Myzus persicae: EST sequencing, SNP identification, and microarray design

<p>Abstract</p> <p>Background</p> <p>The green peach aphid, <it>Myzus persicae </it>(Sulzer), is a world-wide insect pest capable of infesting more than 40 plant families, including many crop species. However, despite the significant damage inflicted by <it>M. persicae </it>in agricultural systems through direct feeding damage and by its ability to transmit plant viruses, limited genomic information is available for this species.</p> <p>Results</p> <p>Sequencing of 16 <it>M. persicae </it>cDNA libraries generated 26,669 expressed sequence tags (ESTs). Aphids for library construction were raised on <it>Arabidopsis thaliana</it>, <it>Nicotiana benthamiana</it>, <it>Brassica oleracea, B. napus</it>, and <it>Physalis floridana </it>(with and without <it>Potato leafroll virus </it>infection). The <it>M. persicae </it>cDNA libraries include ones made from sexual and asexual whole aphids, guts, heads, and salivary glands. <it>In silico </it>comparison of cDNA libraries identified aphid genes with tissue-specific expression patterns, and gene expression that is induced by feeding on <it>Nicotiana benthamiana</it>. Furthermore, 2423 genes that are novel to science and potentially aphid-specific were identified. Comparison of cDNA data from three aphid lineages identified single nucleotide polymorphisms that can be used as genetic markers and, in some cases, may represent functional differences in the protein products. In particular, non-conservative amino acid substitutions in a highly expressed gut protease may be of adaptive significance for <it>M. persicae </it>feeding on different host plants. The Agilent eArray platform was used to design an <it>M. persicae </it>oligonucleotide microarray representing over 10,000 unique genes.</p> <p>Conclusion</p> <p>New genomic resources have been developed for <it>M. persicae</it>, an agriculturally important insect pest. These include previously unknown sequence data, a collection of expressed genes, molecular markers, and a DNA microarray that can be used to study aphid gene expression. These resources will help elucidate the adaptations that allow <it>M. persicae </it>to develop compatible interactions with its host plants, complementing ongoing work illuminating plant molecular responses to phloem-feeding insects.</p

Interactions “Candidatus Liberibacter solanacearum”—Bactericera cockerelli: Haplotype Effect on Vector Fitness and Gene Expression Analyses

“Candidatus Liberibacter solanacearum” (Lso) has emerged as a serious threat world-wide. Five Lso haplotypes have been identified so far. Haplotypes A and B are present in the Americas and/or New Zealand, where they are vectored to solanaceous plants by the potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Triozidae). The fastidious nature of these pathogens has hindered the study of the interactions with their eukaryotic hosts (vector and plant). To understand the strategies used by these pathogens to infect their vector, the effects of each Lso haplotype (A or B) on psyllid fitness was investigated, and genome-wide transcriptomic and RT-qPCR analyses were performed to evaluate Lso gene expression in association with its vector. Results showed that psyllids infected with haplotype B had significantly lower percentage of nymphal survival compared to psyllids infected with haplotype A. Although overall gene expression across Lso genome was similar between the two Lso haplotypes, differences in the expression of key candidate genes were found. Among the 16 putative type IV effector genes tested, four of them were differentially expressed between Lso haplotypes, while no differences in gene expression were measured by qPCR or transcriptomic analysis for the rest of the genes. This study provides new information regarding the pathogenesis of Lso haplotypes in their insect vector. (Résumé d'auteur

Características clinicopatológicas e índice de masa corporal en mujeres Uruguayas portadoras de cáncer de mama asistidas en el Hospital de Clínicas

Objective. To describe the clinicopathological characteristics of breast cancer (BC) in overweight/obese women and their management in clinical practice, focusing on Uruguayan patients treated in the Oncology Department of Hospital de Clínicas. Materials and Methods. This was an observational, descriptive, retrospective, cross-sectional study that included patients diagnosed with BC at the aforementioned center from January 2020 to May 2022. We evaluated demographic variables, Body Mass Index (BMI), histological subtype, hormonal receptors, HER2/neu status, and received treatments. Statistical Tests: Descriptive statistics such as mean and standard deviation were utilized, along with analytical tests like chi-square and Student's t-test for independent samples. Descriptive: Mean and standard deviation for quantitative variables; frequencies for qualitative variables. Analytical: Chi-square for qualitative variables and Student's t-test for quantitative variables. Results. A total of 141 patients were included, 56% of whom were overweight/obese. The median age at diagnosis was similar for both groups: 58 vs. 58.8 years (p=0.762). Among overweight/obese patients, ductal carcinoma (p=0.005) and mastectomy (p=0.012) were more frequent, while luminal tumors showed no statistical significance. In contrast, patients with normal weight were more likely to have lobular carcinoma (p=0.043) and conservative surgery (p=0.012), but triple-negative tumors were not statistically significant. The proportion of patients experiencing recurrence was similar in both groups (p=0.48). Conclusions. In our study, overweight and obesity were not related to most of the characteristics of breast cancer, but they were associated with the histological type and the kind of surgical treatment. No significant differences were observed in the recurrence rate between the two groups of patients.Objetivo. Describir las características clinicopatológicas del cáncer de mama (CM) en mujeres con sobrepeso/obesidad y su manejo en la práctica clínica, en pacientes uruguayas asistidas en Servicio de Oncología del Hospital de Clínicas. Material y métodos. Estudio observacional, descriptivo, retrospectivo de corte transversal, que incluyó a pacientes con diagnóstico de CM del centro ya mencionado, desde enero de 2020 a mayo de 2022. Se evaluaron las variables demográficas, índice de masa corporal, subtipo histológico, receptores hormonales, HER 2neu y tratamiento recibido. Pruebas estadísticas: media y desvío estándar. Analíticas: Chi cuadrado para variables cualitativas y test de Student para variables cuantitativas. Resultados. Se incluyeron 141 pacientes, 56% presentaba sobrepeso/obesidad. La mediana de edad al momento del diagnóstico fue similar para ambos grupos: 58 vs. 58.8 años (p =0.762). Entre las pacientes con sobrepeso/obesidad fueron más frecuente: el carcinoma ductal (p = 0.005); los tumores luminales, aunque sin significancia estadística, y la mastectomía (p =0.012). Mientras que entre las pacientes con normopeso fueron más frecuente: el carcinoma lobulillar (p = 0.043), los tumores triple negativos si bien estos valores no fueron estadísticamente significativos y la cirugía conservadra (CC) (p =0.012).La proporción de pacientes que presentaron recaída fue similar en ambos grupos (p =0.48). Conclusiones. En nuestro estudio el sobrepeso y la obesidad no se relacionaron con la mayoría de las características del CM, pero sí en el tipo histológico y tipo de tratamiento quirúrgico. No se observaron diferencias significativas en la tasa de recaída entre los dos grupos de pacientes.Introdução: O câncer de mama (CM) é o câncer mais frequente e a principal causa de morte por câncer em mulheres em todo o mundo e no Uruguai. Embora a sua etiologia seja desconhecida, são reconhecidos vários fatores de risco envolvidos na sua génese, sendo o sobrepeso e a obesidade fatores de risco modificáveis ​​e por isso de vital interesse. Objetivo: conhecer as características clinicopatológicas do CM em mulheres com sobrepeso/obesidade atendidas na Unidade de Mastologia do Serviço de Oncologia do Hospital de Clínicas e seu manejo na prática clínica. Material e métodos: Estudo transversal observacional, descritivo, retrospectivo, que incluiu pacientes diagnosticados com CM do Serviço de Oncologia do Hospital de Clínicas no período de janeiro de 2020 a maio de 2022. Variáveis ​​demográficas, índice de massa corporal, subtipo histológico, receptores hormonais, HER 2neu e tratamento recebido. Resultados: foram incluídos 141 pacientes, não foram encontradas associações estatisticamente significativas na maioria das variáveis ​​clínico-patológicas e prognósticas estudadas. No entanto, o subtipo histológico e o tratamento cirúrgico apresentaram resultados significativos na comparação entre pacientes com peso normal e pacientes com sobrepeso/obesidade. Conclusões: O escopo limitado deste trabalho não permite que seus resultados sejam extrapolados como representativos da população de mulheres com CM no Uruguai, mas fornece evidências empíricas que buscam contribuir para pesquisas futuras no campo de estudo. Ainda é necessário continuar avançando no entendimento da relação do índice de massa corporal (IMC) com a incidência e prognóstico do CM

Immunity and other defenses in pea aphids, Acyrthosiphon pisum

The genome of the pea aphid Acyrthosiphon pisum lacks genes thought to be crucial in other insects for recognition, signaling and killing of microbes

Treatment of Rapamycin and Evaluation of an Autophagic Response in the Gut of <i>Bactericera cockerelli</i> (Sulč)

Autophagy is a catabolic process that results in the autophagosomic–lysosomal degradation of bulk cytoplasmic content, abnormal protein aggregates, and excess of/or damaged organelles to promote cell survival. Autophagy is also a component of innate immunity in insects and is involved in the clearance of pathogens, including bacteria. The potato psyllid, Bactericera cockerelli, transmits the plant bacterial pathogen ‘Candidatus Liberibacter solanacearum’ (Lso) in the Americas and causes serious damage to solanaceous crops. Our previous studies showed that autophagy could be involved in the psyllid response to Lso and could affect pathogen acquisition. However, the tools to evaluate this response have not been validated in psyllids. To this end, the effect of rapamycin, a commonly used autophagy inducer, on potato psyllid survival and the expression of autophagy-related genes was evaluated. Further, the autophagic activity was assessed via microscopy and by measuring the autophagic flux. Artificial diet-feeding assays using rapamycin resulted in significant psyllid mortality, an increase in the autophagic flux, as well as an increase in the amount of autolysosomes. This study represents a stepping stone in determining the role of autophagy in psyllid immunity

Expression analysis of vitellogenins in the workers of the red imported fire ant (Solenopsis invicta)

Vitellogenin has been proposed to regulate division of labor and social organization in social insects. The red imported fire ant (Solenopsis invicta) harbors four distinct, adjacent vitellogenin genes (Vg1, Vg2, Vg3, and Vg4). Contrary to honey bees that have a single Vg ortholog as well as potentially fertile nurses, and to other ant species that lay trophic eggs, S. invicta workers completely lack ovaries or the ability to lay eggs. This provides a unique model to investigate whether Vg duplication in S. invicta was followed by subfunctionalization to acquire non-reproductive functions and whether Vg was co-opted to regulate behavior within the worker caste. To investigate these questions, we compared the expression patterns of S. invicta Vg genes among workers from different morphological subcastes or performing different tasks. RT-qPCRs revealed higher relative expression of Vg1 in major workers compared to both medium and minor workers, and of Vg2 in major workers when compared to minor workers. Relative expression of Vg1 was also higher in carbohydrate foragers when compared to nurses and protein foragers. By contrast, the level of expression of Vg2, Vg3, and Vg4 were not significantly different among the workers performing the specific tasks. Additionally, we analyzed the relationship between the expression of the Vg genes and S-hydroprene, a juvenile hormone analog. No changes in Vg expression were recorded in workers 12 h after application of the analog. Our results suggest that in S. invicta the Vg gene underwent subfunctionalization after duplication to new functions based on the expression bias observed in these data. This may suggest an alternative and still unknown function for Vg in the workers that needs to be investigated further

Lasting consequences of psyllid (\u3ci\u3eBactericera cockerelli\u3c/i\u3e L.) infestation on tomato defense, gene expression, and growth

Background: The tomato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae), is a pest of solanaceous crops such as tomato (Solanum lycopersicum L.) in the U.S. and vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’. Currently, the only effective strategies for controlling the diseases associated with this pathogen involve regular pesticide applications to manage psyllid population density. However, such practices are unsustainable and will eventually lead to widespread pesticide resistance in psyllids. Therefore, new control strategies must be developed to increase host-plant resistance to insect vectors. For example, expression of constitutive and inducible plant defenses can be improved through selection. Currently, it is still unknown whether psyllid infestation has any lasting consequences on tomato plant defense or tomato plant gene expression in general. Results: In order to characterize the genes putatively involved in tomato defense against psyllid infestation, RNA was extracted from psyllid-infested and uninfested tomato leaves (Moneymaker) 3 weeks post-infestation. Transcriptome analysis identified 362 differentially expressed genes. These differentially expressed genes were primarily associated with defense responses to abiotic/biotic stress, transcription/translation, cellular signaling/transport, and photosynthesis. These gene expression changes suggested that tomato plants underwent a reduction in plant growth/health in exchange for improved defense against stress that was observable 3 weeks after psyllid infestation. Consistent with these observations, tomato plant growth experiments determined that the plants were shorter 3 weeks after psyllid infestation. Furthermore, psyllid nymphs had lower survival rates on tomato plants that had been previously psyllid infested. Conclusion: These results suggested that psyllid infestation has lasting consequences for tomato gene expression, defense, and growth

Influence of juvenile hormone analog on behavior in the red imported fire ant, Solenopsis invicta

Abstract Division of labor is a hallmark characteristic of social insect colonies. While it is understood that worker differentiation is regulated through either the queen or her brood, the understanding of the physiology behind task regulation varies within social species. Studies in eusocial insects have shown that juvenile hormone (JH) is associated with division of labor and the onset of foraging tasks. Although, outside of a few key species, this interaction has yet to be elucidated in the red imported fire ant, Solenopsis invicta. In this study, we evaluated the role of a JH analog, S-hydroprene in worker task transition in Solenopsis invicta. S-hydroprene was applied to nurses to observe behavioral changes. S-hyroprene application to nurses did not affect phototaxis, but there was a shift in behavior from internal, nest-based behaviors to external, foraging-based behaviors. These results show that JH may be implicated in worker task transition in S. invicta and may function similarly as it does in other eusocial insects