Members of the genus Mycoplasma and related organisms impose a substantial burden of infectious diseases on humans and animals, but the last comprehensive review of mycoplasmal pathogenicity was published 20 years ago. Post-genomic analyses have now begun to support the discovery and detailed molecular biological characterization of a number of specific mycoplasmal virulence factors. This review covers three categories of defined mycoplasmal virulence effectors: 1) specific macromolecules including the superantigen MAM, the ADP-ribosylating CARDS toxin, sialidase, cytotoxic nucleases, cell-activating diacylated lipopeptides, and phosphocholine-containing glycoglycerolipids; 2) the small molecule effectors hydrogen peroxide, hydrogen sulfide, and ammonia; and 3) several putative mycoplasmal orthologs of virulence effectors documented in other bacteria. Understanding such effectors and their mechanisms of action at the molecular level connects the biology of the bacteria to direct effects on the host and host responses they elicit, and is expected to translate into new interventions for human and veterinary mycoplasmosis.

It is essential to have a thorough knowledge of the genetic variation among different strains of Xanthomonas citri pv. citri (Xcc), which is responsible for causing citrus bacterial canker. This understanding is important for studying the disease’s characteristics, population structure, and evolution, and ultimately for developing sustainable methods of control. A total of 48 strains, obtained from citrus production areas in Burkina Faso in 2012, 2020, and 2021, were subjected to polymerase chain reaction (PCR) tests using specific primers. The aim was to examine the distribution of type 3 effectors (T3E) and determine the geographical origins of the strains. The examination of the distribution of type 3 non-transcription activate like effectors (TALE) indicates a broader range in strains obtained in 2020 and 2021 compared to those obtained in 2012. However, all strains possess a shared set of three genes, specifically XopE2, XopN, and AvrBs2. Furthermore, all examined effectors were observed in the Bobo-Dioulasso region. Regarding the characterization of TALEs, two profiles containing two to three TALEs were discovered. Profile 1, consisting of two TALEs, was found in 37 Xcc strains, whereas Profile 2, comprising three TALEs, was detected in 11 strains. Out of the three TALEs (A, B, and C) that were identified, TALEs B and C were present in all strains. The correlation matrix indicated a positive association between the T3E content of strains and the duration of their isolation. Principal component analysis revealed a limited organization of the strains under investigation

A comprehensive understanding of the genetic diversity among strains of Xanthomonas citri pv. citri (Xcc), the causative agent of citrus bacterial canker, is crucial for unraveling the pathological nature, structure, and evolution of populations, thereby facilitating the adoption of sustainable control measures. In a collection of 48 strains isolated in 2012, 2020, and 2021 from citrus production areas in Burkina Faso, polymerase chain reaction (PCR) tests utilizing specific primers were conducted to investigate the distribution of type 3 effectors (T3E) and the structuring of strains based on their geographical origins. The analysis of the distribution of type 3 non-transcription activate like effectors (TALE) reveals a more extensive repertoire in strains isolated in 2020 and 2021 compared to those isolated in 2012. Nevertheless, all strains share a common repertoire of three genes, namely XopE2, XopN, and AvrBs2. Additionally, all screened effectors were observed in the Bobo-Dioulasso locality. Concerning the characterization of TALEs, two profiles consisting of two to three TALEs were identified. Profile 1, with two TALEs, was present in 37 Xcc strains, while Profile 2, with three TALEs, was identified in 11 strains. Among the three TALEs (A, B, and C) identified, TALEs B and C were common to all strains. The correlation matrix revealed a positive correlation between the T3E content of strains and the years of their isolation. Multiple component analysis indicated a weak structuring of the tested strains.

Phytopathogenic oomycetes are known to infect a host plant successfully due to their ability to secrete a set of protein effectors. Of interest to many researchers are effectors with the N-terminal RxLR motif (Arginine-any amino acid-Leucine-Arginine). Owing to the genome sequencing, we can now comprehend the high level of diversity among oomycete effectors, and similarly, their conservation within and among species core RxLR effectors (CREs). Currently, there are a couple of putative CREs that have been identified in oomycetes. The functional characterization of these CREs proposes their virulence role with the potential of targeting central cellular processes that are conserved across diverse plant species. This could be harnessed in engineering plants for broad-spectrum and durable resistance.

Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is one of the most destructive diseases in banana farming worldwide. Knowledge of the factors of genetic diversity and virulence of the pathogen contributes to the development of resistant cultivars and in management strategies based on exclusion. In this study, phenotypic traits such as virulence and aggressiveness in a sample of 52 Foc isolates, were analyzed and their relationship to the presence of putative effectors of gene SIX (Secreted in Xylem) pathogenicity homologues, verified. According to the dissimilarity matrix, there were three isolates closest to the standard Foc race 1 strain. Isolates 229A and 218A, were selected according to their aggressiveness profile in 'Grand Naine' and 'Prata-Anã', respectively, I order to replace the standard isolate of race 1 in the resistance screening process carried out by the breeding program. Two homologues of the SIX8 gene, SIX8a and SIX8b, are present in isolates of Foc from Brazil and the SIX8b gene correlates with avirulence in the cultivar ‘Grand Naine’ (Cavendish). These results are important to support the banana genetic breeding program by identification of sources of resistance to Foc and contribute in the establishment of the function of SIX effector proteins.

Herbivores have evolved several strategies to cope with plant defences. Some herbivores are able to resist toxic compounds, while others can manipulate host immunity. Previously it was found that spider mites collected from non-solanaceous wild host plants consist mostly of individuals that induce tomato defences, but also at low frequencies of individuals that can suppress these defences. Also, it has been shown that mites collected from non-solanaceous plants can adapt to tomato by evolving traits that allow them to suppress defences. Hence, we wanted to know if this trait is also common among mites naturally occurring on tomatoes. Here, we compared three T. urticae populations sampled from tomato at three field sites, and also an outbred population created from them through controlled crosses. We then assessed their fecundity on wild-type (WT) tomato plants and def-1 mutants impaired in inducible JA-defences. We also assessed the magnitude of JA defences they induce in WT plants to discriminate between resistant types (high induction and high performance) and those that can suppress defences (low induction, high performance). We then aligned these data with data on variation in mitochondrial DNA cytochrome oxidase I (COI) and effector 84 (a suppressor of JA-defences in planta), in order to compare genetic diversity patterns among mite lines that induce or suppress defences. We found that suppression is the dominant phenotype in mite strains collected from field-grown tomatoes and that inducers and suppressors predominantly cluster in distinct effector 84 clades. We speculate that effector allelic diversity may be subject to natural selection when these mites colonize a novel host plant, promoting traits to cope with plant resistance, such as defence suppression, which facilitates adaptation.

The type 6 protein secretion system (T6SS) is prevalently utilized by Gram-negative bacteria to compete for resources and space. Upon activation, toxic effectors from this secretion system are translocated into the competitor prokaryote or eukaryote in a contact-dependent manner. While much has been reported on T6SS-mediated prokaryotic competition, very little is understood about the mechanisms of bacterial interactions with eukaryotic hosts. Likewise, many virulent T6SS effectors are known to be antibacterial. In recent years, however, evidence has emerged on numerous T6SS effectors that interact with related immunity proteins in a range of eukaryotic hosts. Insights into how this effector-immunity pairing alters the physiological responses of the recipient organism might provide opportunities relating to the T6SS agricultural and biotherapeutic applications. We, therefore, summarize the impacts of the T6SS effectors with a special focus on bacterial interactions with animals, plants, and fungi. We further briefly discuss pipelines that are currently used to characterize antieukaryotic T6SS effectors.

Parallel manipulators with multiple end-effectors bring us interesting advantages over conventional parallel manipulators such as improved manipulability, workspace and avoidance of singularities. In this work the kinematics of a five-bar planar parallel manipulator equipped with two end-effectors is approached by means of the theory of screws. As an intermediate step the displacement analysis of the robot is also investigated. The input-output equations of velocity and acceleration are systematically obtained by resorting to reciprocal-screw theory. In that regard the Klein form of the Lie algebra se(3) of the Euclidean group SE(3) plays a central role. In order to exemplify the method of kinematic analysis, a case study is included. Furthermore, the numerical results obtained by means of the theory of screws are confirmed with the aid of special software like ADAMS.^TM

The soybean aphid (SBA; Aphis glycines Matsumura) and the soybean cyst nematode (SCN; Heterodera glycines Ichninohe) are major pests of the soybean (Glycine max (L.) Merr.). Independent studies on these pests have made substantial progress in understanding the genetic basis of limiting these pests in both model and non-model plant systems. Classical linkage mapping and genome-wide association studies (GWAS) have identified some major and minor QTLs in soybean. The studies on interactions of aphid and nematode effectors with host proteins allow us to identify molecular cues in various signaling components, including plant disease resistance and phytohormone genes. Here we review various resistance components of both SBA and SCN in terms of their effectors, their role in eliciting or attenuating host defense and update on findings on key quantitative trait loci (QTLs)/genes in soybean that could help in mitigating these widespread shifted virulent soybean aphid and SCN populations. We also provide an update on recent interaction studies of soybean-soybean aphid-SCN as well as interaction studies involving different aphids/nematodes and their host systems. PHYTOALEXIN DEFICIENT4 (PAD4) in soybean could possibly play a major role in providing resistance against both soybean aphid and SCN.

Galls are characteristic plant structures formed by cell size enlargement and/or cell proliferation induced by parasitic or pathogenic organisms. Insects are a major inducer of galls, and insect galls can occur on plant leaves, stems, floral buds, flowers, fruits, or roots. Many of these exhibit unique shapes, providing shelter and nutrients to insects. To form unique gall structures, gall-inducing insects are believed to secrete certain effector molecules and hijack host developmental programs. However, the molecular mechanisms of insect gall induction and development remain largely unknown due to the difficulties associated with the study of non-model plants in the wild. Recent advances in next-generation sequencing have allowed us to determine the biological processes in non-model organisms, including gall-inducing insects and their host plants. In this review, we first summarize the adaptive significance of galls for insects and plants. Thereafter, we summarize recent progress regarding the molecular aspects of insect gall formation.