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PubMed2026

Revealing Functional Traits of Insect Pest Suppressive Rhizobacterial Strains Through Comparative Genomics.

Root inoculation with rhizobacteria is an emerging strategy to enhance plant resistance to aphid herbivory, yet the microbial functional traits underpinning these responses remain poorly characterised. Here, we present a comparative genomic analysis of five rhizobacteria (Acidovorax radicis N35, Bacillus subtilis B171, Bacillus velezensis FZB42, Rhizobium radiobacter F4 and Pseudomonas simiae WCS417r) that suppress aphids when inoculated onto barley. As expected, functional variation largely reflected phylogenetic relatedness; however, candidate traits implicated in modulation of plant immune defences were conserved across all strains, including biosynthesis of 2,3-butanediol, riboflavin and salicylic acid. Additional shared functions, linked to plant defence signalling, included phytoene and squalene biosynthesis (absent in P. simiae) and N-acyl homoserine lactone quorum sensing (absent in Bacillus spp.). Strain-specific traits were also identified, including surfactin production in Bacillus spp. and hydrogen cyanide biosynthesis in A. radicis and P. simiae. Comparison with a broader collection of rhizobacteria revealed that many putative plant-beneficial functions identified were widely conserved, including among closely related phytopathogens. This extensive functional overlap suggests aphid suppression cannot be explained solely by presence or absence of broad functional traits, but rather by specific trait combinations, regulatory differences, or context-dependent expression. This highlights the need for genome-informed approaches for bioinoculant discovery.

Animals↗
PubMed2006

Tomato chlorotic mottle virus is a target of RNA silencing but the presence of specific short interfering RNAs does not guarantee resistance in transgenic plants.

Tomato chlorotic mottle virus (ToCMoV) is a begomovirus found widespread in tomato fields in Brazil. ToCMoV isolate BA-Se1 (ToCMoV-[BA-Se1]) was shown to trigger the plant RNA silencing surveillance in different host plants and, coinciding with a decrease in viral DNA levels, small interfering RNAs (siRNAs) specific to ToCMoV-[BA-Se1] accumulated in infected plants. Although not homogeneously distributed, the siRNA population in both infected Nicotiana benthamiana and tomato plants represented the entire DNA-A and DNA-B genomes. We determined that in N. benthamiana, the primary targets corresponded to the 5' end of AC1 and the embedded AC4, the intergenic region and 5' end of AV1 and overlapping central part of AC5. Subsequently, transgenic N. benthamiana plants were generated that were preprogrammed to express double-stranded RNA corresponding to this most targeted portion of the virus genome by using an intron-hairpin construct. These plants were shown to indeed produce ToCMoV-specific siRNAs. When challenge inoculated, most transgenic lines showed significant delays in symptom development, and two lines had immune plants. Interestingly, the levels of transgene-produced siRNAs were similar in resistant and susceptible siblings of the same line. This indicates that, in contrast to RNA viruses, the mere presence of transgene siRNAs corresponding to DNA virus sequences does not guarantee virus resistance and that other factors may play a role in determining RNA-mediated resistance to DNA viruses.

Begomovirus↗
PubMed1981

The specificity of anti-A agglutinins from immunized rabbits and plant lectins.

A+ and A- rabbits were immunized with human A red cells, saliva of A+ or A- rabbits or human A.Se. A- rabbits responded well against A.Se saliva and A cells and slightly against A+ saliva, whereas A+ rabbits produced high-titered antibody against A cells which was abolished by absorption with O cells. Agglutination inhibition tests showed that anti-A from A- rabbits immunized with A.Se or A cells was not inhibited with A+ saliva, and anti-A from rabbits immunized with A cells was not absorbed with A.Se saliva. Hydroxylapatite chromatography separated each of A.Se and A+ saliva into three fractions of which the 1st and 3rd fractions of A.Se and only the 3rd of A+ had A activity. The 3rd fraction of A.Se and A+ did not inhibit anti-A from any rabbits immunized but the 1st of A.Se inhibited anti-A from all rabbits except for A+ immunized with A cells. The 1st and 2nd fractions reacted slightly with anti-A from A- immunized with A+ and from A+ immunized with A cells. D. biflorus anti-A distinguished human A from rabbit one but Mushroom anti-A could not. These results suggested qualitative differences between human and rabbit saliva A antigens.

ABO Blood-Group System↗
PubMed2003

Loss of actin cytoskeletal function and EDS1 activity, in combination, severely compromises non-host resistance in Arabidopsis against wheat powdery mildew.

Plant immunity against the majority of the microbial pathogens is conveyed by a phenomenon known as non-host resistance (NHR). This defence mechanism affords durable protection to plant species against given species of phytopathogens. We investigated the genetic basis of NHR in Arabidopsis against the wheat powdery mildew fungus Blumeria graminis f. sp. tritici (Bgt). Both primary and appressorial germ tubes were produced from individual Bgt conidia on the surface of the Arabidopsis leaves. Attempted infection occasionally resulted in successful penetration, which led to the development of an abnormal unilateral haustorium. Inoculation of a series of Arabidopsis defence-related mutants with Bgt resulted in the attenuation of reactive oxygen intermediate (ROI) production and salicylic acid (SA)-dependent defence gene expression in eds1, pad4 and nahG plants, which are known to be defective in some aspects of host resistance. Furthermore, Bgt often developed bilateral haustoria in the mutant Arabidopsis lines that closely resembled those formed in wheat. A similar decrease in NHR was observed following treatment of the wild-type Arabidopsis plants with cytochalasin E, an inhibitor of actin microfilament polymerisation. In eds1 mutants, inhibition of actin polymerisation severely compromised NHR in Arabidopsis against Bgt. This permitted completion of the Bgt infection cycle on these plants. Therefore, actin cytoskeletal function and EDS1 activity, in combination, are major contributors to NHR in Arabidopsis against wheat powdery mildew.

Actins↗
PubMedDate not supplied

[Clinico-immunological and allergological characteristics of population of the Middle ural].

Clinical investigation of immune and allergic state of 633 adult dwellers of the Middle Ural region was carried out. The first (occupational) group consisted of 479 workers of the industrial plant, most of which exposed to negative factors such as radiation, harmful chemical substances and stress. The second (control) group consisted of 154 town-dwellers, who did not work at the industrial plant. Immune state was assessed in 714 people. Clinical symptoms of immune deficiency were found in 67% of the occupational group and in 76% of the control group. Allergic condition and allergic-infection syndrome were common for both groups, the rate of infection syndrome being relatively low. The immune state of the occupational group showed in comparison to control reliable increase in absolute and relative amount of T-lymphocytes, in the ratio CD4+/CD8+ and in the level of serum IgG. It was found also the decrease in the concentration of T-killers, the amount of NK cells and B-lymphocytes, phagocyte activity and the level of serum IgA. It was suggested that regional and ecological peculiarities influence the immune state rather than induce clinical symptoms of immune deficiency.

Adult↗
PubMed2003

Antagonistic control of oxidative stress-induced cell death in Arabidopsis by two related, plant-specific zinc finger proteins.

The most familiar form of plant programmed cell death is the hypersensitive response (HR) associated with successful plant immune responses. HR is preceded by an oxidative burst and the generation of both reactive oxygen intermediates (ROI) and NO. The Arabidopsis LSD1 gene encodes a negative regulator of plant programmed cell death that meets several criteria for a regulator of processes relevant to ROI management during pathogen responses. Here we demonstrate that a highly conserved LSD1 paralogue, LOL1, acts as a positive regulator of cell death. Manipulation of LOL1 expression alters both the superoxide-dependent, runaway cell death phenotype of lsd1 plants and the normal HR. We also show that LSD1 and LOL1 have antagonistic effects on copper-zinc superoxide dismutase accumulation, consistent with functions in cell death control via maintenance of ROI homeostasis.

Apoptosis↗
PubMed2003

The jasmonate biochemical pathway.

Plants possess an interrelated and interacting family of potent fatty acid-derived regulators--the jasmonates. These compounds, which play roles in both defense and development, are derived from tri-unsaturated fatty acids [alpha-linolenic acid (18:3) or 7Z,10Z,13Z-hexadecatrienoic acid (16:3)]. The lipoxygenase-catalyzed addition of molecular oxygen to alpha-linolenic acid initiates jasmonate synthesis by providing a 13-hydroperoxide substrate for the formation of an unstable allene oxide that is then subject to enzyme-guided cyclization to produce 12-oxo-phytodienoic acid (OPDA). OPDA, a key regulatory lipid in the plant immune system, has several fates, including esterification into plastid lipids or transformation into the 12-carbon co-regulator jasmonic acid (JA). JA, the best-characterized member of the family, regulates both male and female fertility (depending on the plant species), and is an important mediator of defense gene expresssion. JA is itself a substrate for further diverse modifications. Genetic dissection of the pathway is revealing how the different jasmonates modulate different physiological processes. Each new family member that is discovered provides another key to understanding the fine control of gene expression in immune responses, in the initiation and maintenance of long-distance signal transfer in response to wounding, and in the regulation of fertility, among other processes. The Jasmonate Biochemical Pathway provides an overview of the growing jasmonate family, and new members will be included in future versions of the Connections Map. Science Viewpoint R. Liechti, E. E. Farmer, The jasmonate pathway. Science 296, 1649-1650 (2002). [Abstract] [Full Text]

Acetates↗
PubMed2026

A cooperative regulatory module between TAGL2 and JMJC1 activates specific defense genes against root-knot nematodes in tomato.

Plant-parasitic nematodes (PPNs) threaten global food security. Although epigenetic modifications are crucial for plant immunity, how histone modifiers contribute to root-knot nematodes (RKNs, Meloidogyne incognita) resistance remains unclear. Here, using genetic, molecular and biochemical approaches, we investigated the epigenetic and transcriptional mechanisms underlying RKN resistance mediated by the histone demethylase (HDM) JMJC1 and the MADS-box transcription factor TAGL2 in tomato (Solanum lycopersicum). We identified JMJC1 as an RKN-induced positive defense regulator targeting H3K9me3 and H3K27me3 histone marks. JMJC1 physically interacts with TAGL2, which also positively regulates RKN resistance. Transcriptomic analysis indicated that TAGL2 regulates multiple layers of the plant defense network, transcriptionally activating representative genes from distinct pathways (including PUB10, bHLH98, CCaMK, and SAUR3), which we validated as positive regulators of RKN resistance via virus-induced gene silencing (VIGS). At the chromatin level, TAGL2 and JMJC1 co-regulate these loci, associating with localized H3K9me3 and H3K27me3 reduction. Furthermore, TAGL2 directly activates JMJC1 transcription, establishing a positive feedback loop that amplifies immune signaling. Our findings reveal a cooperative model wherein a HDM and a transcription factor coordinate at specific loci to fine-tune multiple defense layers at both epigenetic and transcriptional levels, providing insights for breeding durable nematode-resistant plants.

Solanum lycopersicum↗
PubMed2026

Rapidly evolving aphid gall effector proteins exhibit saposin-like folds.

Many insects manipulate plants by injecting effector proteins. In one extreme example of this molecular "hijacking", Hormaphis cornu aphids inject bicycle proteins into Hamamelis virginiana (Witch Hazel), contributing to the development of novel organs called galls. Bicycle proteins share no amino acid sequence similarity with proteins of known function. Here, we report the crystal structures of two divergent bicycle proteins. Both proteins contain saposin-like folds: one with multiple disulfide bonds exhibits a helix swap; the other has no disulfide bonds and possesses two tandem domains. To explore the structural evolution of bicycle proteins, we predicted bicycle protein structures with Alphafold2 (AF2). While AF2 did not recover the two experimental structures using existing databases, it succeeded after we provided multiple sequence alignments (MSAs) containing protein sequences encoded in new genome sequences from closely related aphid species. Using this customized approach at scale, we generated 2400 high-confidence predictions for bicycle proteins from seven aphid species. This dataset revealed that bicycle proteins without cysteines are outliers in fold space and appear to have evolved from ancestral proteins with disulfide-bonded saposin-like folds. While all bicycle proteins contain predicted saposin-like folds, they display a vast diversity of structural and physicochemical properties. While this diversity thwarts prediction of conserved functions encoded in structure, it suggests that bicycle proteins have evolved to target diverse plant processes and/or to evade plant immune surveillance.

AlphaFold predictions↗
PubMed2007

Small molecule approaches in plants.

Small molecules offer exciting opportunities for plant science. So far, bioactive small molecules have been identified as plant hormones, herbicides, growth regulators, or taken from animal research. Recently, plant scientists have started to explore further the chemical space for novel modulators of plant hormone signalling, and have followed up this work with exciting discoveries illustrating the potential of small molecules such as brassinazole and sirtinol. New chemical genetic screens have been designed to generate chemical tools for the investigation of membrane trafficking, gravitropism and plant immunity. Further novel 'chemetic' tools to identify targets and modes of action are currently generated through an intimate interdisciplinary collaboration between biologists and small molecule chemists.

Benzamides↗
PubMed2007

Biological systems of the host cell involved in Agrobacterium infection.

Genetic transformation of plants by Agrobacterium, which in nature causes neoplastic growths, represents the only known case of trans-kingdom DNA transfer. Furthermore, under laboratory conditions, Agrobacterium can also transform a wide range of other eukaryotic species, from fungi to sea urchins to human cells. How can the Agrobacterium virulence machinery function in such a variety of evolutionarily distant and diverse species? The answer to this question lies in the ability of Agrobacterium to hijack fundamental cellular processes which are shared by most eukaryotic organisms. Our knowledge of these host cellular functions is critical for understanding the molecular mechanisms that underlie genetic transformation of eukaryotic cells. This review outlines the bacterial virulence machinery and provides a detailed discussion of seven major biological systems of the host cell-cell surface receptor arrays, cellular motors, nuclear import, chromatin targeting, targeted proteolysis, DNA repair, and plant immunity--thought to participate in the Agrobacterium-mediated genetic transformation.

Active Transport, Cell Nucleus↗
PubMed2002

Expression and inheritance of hypersensitive resistance to rice hoja blanca virus mediated by the viral nucleocapsid protein gene in transgenic rice.

Rice hoja blanca virus (RHBV) is a major virus disease of economic importance affecting rice in northern South America, Central America and the Caribbean. This is the first report of transgenic resistance to RHBV and the transformation of an indica rice variety from Latin America. Rice transformed with the RHBV nucleocapsid protein ( N) gene had a significant reduction in disease development. Several reactions were observed that ranged from susceptible to completely resistant plants (immunity). The resistant reactions were characterized by the production of local lesions like a hypersensitive reaction or a recovery phenotype with the emergence of symptom-less new leaves. These transgenic RHBV-resistant rice lines expressed the N gene RNA at low levels that were below the detection limit by Northern blots and only resolved by RT-PCR. The nucleocapsid protein could not be detected in any of the transgenic plants either by Western or ELISA tests. These results suggest that the resistance encoded by the N gene in these plants appears to be mediated by RNA. When challenged with RHBV, the resistant transgenic lines showed a significant increased performance for important agronomic traits including the number of tillers, the number of grains per plant and the yield as compared to the susceptible control. Furthermore, upon inoculation some of the most-resistant transgenic lines showed agronomic traits similar to the uninoculated non-transgenic Cica 8 control. Using both agronomic traits and disease severity as criteria, several of the most-resistant lines were followed through the R(4) generation and demonstrated that the N gene and RHBV resistance was inherited in a stable manner. These transgenic rice lines could become a new genetic resource in developing RHBV-resistant cultivars.

Capsid Proteins↗
PubMed2002

Identification and characterization of a novel human plant pathogenesis-related protein that localizes to lipid-enriched microdomains in the Golgi complex.

Group 1 of plant pathogenesis-related proteins (PR-1) and a variety of related mammalian proteins constitute a superfamily of proteins that share structural similarities. Little is known about their function, but all the family members identified to date are co-translationally translocated to the lumen of the endoplasmic reticulum and are secreted as soluble proteins or are targeted to vacuoles. Here we report the identification of a novel family member that localizes to the cytosolic site of the endomembrane system in mammalian cells. After detergent solubilization of isolated Golgi membranes, a 17 kDa protein was found associated with a low-density detergent-insoluble fraction. The amino-acid sequence, determined by microsequencing and molecular cloning, revealed a significant homology with the superfamily of PR-1 proteins. Golgi-associated PR-1 protein (GAPR-1) showed a brefeldin-A-sensitive Golgi localization in immunofluorescence. Interestingly, the protein remained associated with the microdomain fraction in the presence of Brefeldin A. By mass spectrometry, GAPR-1 was shown to be myristoylated. Immunoprecipitation of GAPR- 1 from Golgi membranes resulted in the coimmunoprecipitation of caveolin-1, indicating a direct interaction between these two proteins. Myristoylation, together with protein-protein or electrostatic interactions at physiological pH owing to the highly basic pI of GAPR-1 (pI 9.4) could explain the strong membrane association of GAPR-1. Tissue screening revealed that GAPR-1 is not detectably expressed in liver, heart or adrenal glands. High expression was found in monocytes, leukocytes, lung, spleen and embryonic tissue. Consistent with the involvement of PR-1 proteins in the plant immune system, these data could indicate that GAPR-1 is involved in the immune system.

Amino Acid Sequence↗
PubMed2025

Adaptation of the Cyst Nematode Globodera pallida to the Colinear Potato Resistant QTLs GpaVvrn and GpaVspl Involved Distinct Genomic Regions and Absence of Cross-Virulence.

The use of alternative methods to control cyst nematode populations has accelerated since the ban of chemical nematicides in Europe. The resistant QTL GpaVvrn, derived from the wild species Solanum vernei, is widely present in resistant European potato cultivars and provides strong protection against Globodera pallida populations although a risk of resistance breakdown has already been demonstrated in both experimental evolution studies and field populations. The wild relative S. sparsipilum, harbouring the resistant QTL GpaVspl, would be an interesting alternative source of resistance to control virulent G. pallida. The goal of the present study was to understand the genomics of adaptation of the nematode to these two colinear resistant QTLs. Starting with two natural populations, an experimental evolution approach allowed, after 10 generations on resistant potato genotypes, selecting independent nematode lineages adapted to each QTL. These virulent lineages were analysed through a combination of phenotyping and genome scans approaches. Phenotyping enabled the quantification of virulence levels and confirmed resistance breakdowns. Pool-Seq whole genome sequencing followed by genome scan analyses identified genomic regions under selection, potentially involved in the adaptive mechanisms to each resistance factor. Candidate genes within these regions provided insights into the genetic basis of adaptation, revealing effectors known to suppress plant immunity. As genome scans highlighted distinct genomic regions for the adaptation to both resistant factors, we were able to predict and phenotypically confirm the absence of cross-virulence between nematode lineages evolving on GpaVvrn and GpaVspl. These findings have significant implications for the design of effective and sustainable resistance management strategies.

Animals↗
PubMed1997

The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeats.

The Arabidopsis NPR1 gene controls the onset of systemic acquired resistance (SAR), a plant immunity, to a broad spectrum of pathogens that is normally established after a primary exposure to avirulent pathogens. Mutants with defects in NPR1 fail to respond to various SAR-inducing treatments, displaying little expression of pathogenesis-related (PR) genes and exhibiting increased susceptibility to infections. NPR1 was cloned using a map-based approach and was found to encode a novel protein containing ankyrin repeats. The lesion in one npr1 mutant allele disrupted the ankyrin consensus sequence, suggesting that these repeats are important for NPR1 function. Furthermore, transformation of the cloned wild-type NPR1 gene into npr1 mutants not only complemented the mutations, restoring the responsiveness to SAR induction with respect to PR-gene expression and resistance to infections, but also rendered the transgenic plants more resistant to infection by P. syringae in the absence of SAR induction.

Amino Acid Sequence↗
PubMed2003

[Transgenic potato containing immunogenic gene of avian coronavirus and its immunogenicity in mice].

To check the feasibility of expression of the immunogenic gene of avian coronavirus infectious bronchitis virus (IBV) in plants, the transformation of S1 gene of IBV into potato and the immunogenicity of its expression product was studied. The S1 gene of IBV-ZJ971 strain was inserted into plasmid pBI121 under the control of 35 S promoter. Agrobacterium fumefaciens EHA105 with the recombinant vector pBI121 was obtained by tri-parental mating method. So, an efficient potato transformation system mediated by Agrobacterium fumefaciens was established. The rates of calli and shoots differentiation were 100%, and more than 95% respectively, for transgenic potato with S1 gene of IBV. PCR and Southern blot analyses showed that IBV S1 gene was integrated into genomic DNA of the potato plant and most transgenic plants had two copies of S1 gene of IBV. In our experiments, 47 transgenic plantlets have been obtained. Northern blot and ELISA analyses indicated that most transgenic plants could normally transcribe and translate S1 gene of IBV, though the levels of transcription and translation were different in various transgenic plants. Immunity assay with BALB/C mice showed that expression products of transgenic potato with S1 gene of IBV were immunogenic, and ELISA antibody titer reached 1:20 to 1:40 and 1:80 to 1:160 with doses of 0.5 g and 1 g, respectively. Virus neutralization (VN) antibodies were detected by tracheal organ cultures, and the results showed that VN titers reached respectively 1:160 to 1:320 and 1:320 to 1:2048 with doses of 0.5 g and 1 g.

Animals↗