Novel therapeutic targets, including IGFBP3, of umbilical cord mesenchymal stem-cell-conditioned medium in intrauterine adhesion.

Mesenchymal stem cells play important roles in repairing injured endometrium. However, the molecular targets and potential mechanism of the endometrial recipient cells for stem cell therapy in intrauterine adhesion (IUA) are poorly understood. In this study, umbilical cord mesenchymal stem-cell-conditioned medium (UCMSCs-CM) produced positive effects on a Transforming growth factor beta (TGF-ß) induced IUA cell model. RNA-sequencing was performed on clinical IUA tissues, and the top 40 upregulated and top 20 downregulated mRNAs were selected and verified using high-throughput (HT) qPCR in both tissues and cell models. Based on a bioinformatic analysis of RNA-sequencing and HT-qPCR results, 11 mRNAs were uncovered to be the intervention targets of UCMSCs-CM on IUA endometrium cell models. Among them, IGFBP3 was striking as a key pathogenic gene and a potential diagnostic marker of IUA, which exhibited the area under the curve (AUC), sensitivity, specificity were 0.924, 93.1% and 80.6%, respectively in 60 endometrial tissues. The silencing of IGFBP3 exerted positive effects on the IUA cell model through partially upregulating MMP1 and KLF2. In conclusion, RNA-sequencing combined with HT qPCR based on clinical tissues and IUA cell models were used in IUA research and our results may provide some scientific ideas for the diagnosis and treatment of IUA.

The proteomics analysis of extracellular vesicles revealed the possible function of heat shock protein 60 in Helicobacter pylori infection.

BACKGROUND: Helicobacter pylori (H. pylori) infection is a major risk factor for gastric diseases, including gastritis and gastric cancer. Heat shock protein 60 (HSP60) is a chaperone protein involved in various cellular processes and has been implicated in the immune response to bacterial infections. Extracellular vesicles (EVs) containing various protein components play important roles in cell communication. In the present study, a systematic proteomic analysis of EVs obtained from H. pylori infected cells was performed and the EV-derived HSP60 function was studied. METHODS: EVs were evaluated by nanoparticle tracking analysis, transmission electron microscopy and western blotting. The recognized protein components were quantified by label-free proteomics and subjected to bioinformatics assays. The expression of HSP60 in EVs, host cells and gastric cancers infected by H. pylori was determined by western blotting and immunohistochemical, respectively. In addition, the apoptotic regulation mechanisms of HSP60 in H. pylori infection were analyzed by western blotting and flow cytometry. RESULTS: A total of 120 important differential proteins were identified in the EVs from H. pylori-infected cells and subjected to Gene Ontology analysis. Among them, CD63, HSP-70 and TSG101 were verified via western blotting. Moreover, HSP60 expression was significantly increased in the EVs from H. pylori-infected GES-1 cells. H. pylori infection promoted an abnormal increase in HSP60 expression in GES-1 cells, AGS cells, gastric mucosa and gastric cancer. In addition, knockdown of HSP60 suppressed the apoptosis of infected cells and the expression of Bcl2, and promoted the upregulation of Bax. CONCLUSION: This study provides a comprehensive proteomic profile of EVs from H. pylori-infected cells, shedding light on the potential role of HSP60 in H. pylori infection. The findings underscore the significance of EV-derived HSP60 in the pathophysiology of H. pylori-associated diseases.

Cargoes of exosomes function as potential biomarkers for Mycobacterium tuberculosis infection.

Exosomes as double-membrane vesicles contain various contents of lipids, proteins, mRNAs and non-coding RNAs, and involve in multiple physiological processes, for instance intercellular communication and immunomodulation. Currently, numerous studies found that the components of exosomal proteins, nucleic acids or lipids released from host cells are altered following infection with Mycobacterium tuberculosis. Exosomal contents provide excellent biomarkers for the auxiliary diagnosis, efficacy evaluation, and prognosis of tuberculosis. This study aimed to review the current literatures detailing the functions of exosomes in the procedure of M. tuberculosis infection, and determine the potential values of exosomes as biomarkers to assist in the diagnosis and monitoring of tuberculosis.

The functions and applications of extracellular vesicles derived from Mycobacterium tuberculosis.

Extracellular vesicles (EVs) originating from bacteria function critical roles in bacterial biologic physiology and host-pathogen interactions. Mycobacterium tuberculosis (M. tuberculosis) produces EVs both in vitro and in vivo, with membrane-bound nanoparticles facilitating the transmission of biological molecules including lipids, proteins, nucleic acids and glycolipids, while interacting remotely with the host. Although studies of EVs in mycobacterial infections is still in its infancy, it has already revealed an entirely new aspect of M. tuberculosis-host interactions that may have implications for tuberculosis (TB) pathogenesis. In this review, we discuss the significant functions of M. tuberculosis EVs in elucidating the mechanisms underlying vesicle biogenesis and modulating cellular immune responses, as well as the recent advances and challenges in the development of novel preventive and therapeutic or diagnostic strategies against TB.

Hrip1 enhances tomato resistance to yellow leaf curl virus by manipulating the phenylpropanoid biosynthesis and plant hormone pathway.

Tomato yellow leaf curl virus (TYLCV) causes tremendous losses of tomato worldwide. An elicitor Hrip1, which produced by Alternaria tenuissima, can serve as a pathogen-associated molecular patterns (PAMPs) to trigger the immune defense response in Nicotiana benthamiana. Here, we show that Hrip1 can be targeted to the extracellular space and significantly delayed the development of symptoms caused by TYLCV in tomato. In basis of RNA-seq profiling, we find that 1621 differential expression genes (DEGs) with the opposite expression patterns are enriched in plant response to biotic stress between Hrip1 treatment and TYLCV infection of tomato. Thirty-two known differential expression miRNAs with the opposite expression patterns are identified by small RNA sequencing and the target genes of these miRNAs are significantly enriched in phenylpropanoid biosynthesis, plant hormone signal transduction and peroxisome. Based on the Pearson correlation analysis, 13 negative and 21 positive correlations are observed between differential expression miRNAs and DEGs. These miRNAs, which act as a key mediator of tomato resistance to TYLCV induced by Hrip1, regulate the expression of phenylpropanoid biosynthesis and plant hormone signal transduction-related genes. Taken together, our results provide an insight into tomato resistance to TYLCV induced by PAMP at transcriptional and posttranscriptional levels. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03426-6.

A Novel Protein Elicitor (PELL1) Extracted from Lecanicillium lecanii Induced Resistance against Bemisia tabaci (Hemiptera: Aleyrodidae) in Gossypium hirsutum L.

Protein elicitors play a key role in signaling or displaying plant defense mechanism and emerging as vital tools for biocontrol of insects. This study was aimed at the characterization of the novel protein elicitor isolated from entomopathogenic fungi Lecanicillium lecanii (V3) strain and its activity against whitefly, Bemisia tabaci, in cotton (Gossypium hirsutum L.). The sequence of purified elicitor protein showed 100% similarity with hypothetical protein LEL_00878 (Cordyceps confragosa RCEF 1005) (GenBank accession no. OAA81333.1). This novel protein elicitor has 253 amino acid residues and 762 bp with a molecular mass of 29 kDa. Their combatant protein was expressed in Escherichia coli using pET-28a (+) plasmid. Bioassay was revealed to quantify the impact of numerous concentrations of protein (i.e., 58.32, 41.22, and 35.41 µg/ml) on the fecundity rate of B tabaci on cotton plants. Bioassay results exhibited a significant effect (P ≤ 0.001) of all the concentrations of protein on the fecundity rate of B. tabaci. In addition, the gene expression analysis found a significant upregulation of the major genes associated with salicylic acid (SA) and jasmonic acid (JA) defense pathways in elicitor protein-treated plants. Our results showed that the potential application of novel protein elicitor derived from Lecanicillium lecanii will be used as future biointensive controlling approaches against whitefly, Bemisia tabaci.

Root-Associated Microbiota Response to Ecological Factors: Role of Soil Acidity in Enhancing Citrus Tolerance to Huanglongbing.

The citrus orchards in southern China are widely threatened by low soil pH and Huanglongbing (HLB) prevalence. Notably, the lime application has been used to optimize soil pH, which is propitious to maintain root health and enhance HLB tolerance of citrus; however, little is known about the interactive effects of soil acidity on the soil properties and root-associated (rhizoplane and endosphere) microbial community of HLB-infected citrus orchard. In this study, the differences in microbial community structures and functions between the acidified and amended soils in the Gannan citrus orchard were investigated, which may represent the response of the host-associated microbiome in diseased roots and rhizoplane to dynamic soil acidity. Our findings demonstrated that the severity of soil acidification and aluminum toxicity was mitigated after soil improvement, accompanied by the increase in root activity and the decrease of HLB pathogen concentration in citrus roots. Additionally, the Illumina sequencing-based community analysis showed that the application of soil amendment enriched functional categories involved in host-microbe interactions and nitrogen and sulfur metabolisms in the HLB-infected citrus rhizoplane; and it also strongly altered root endophytic microbial community diversity and structure, which represented by the enrichment of beneficial microorganisms in diseased roots. These changes in rhizoplane-enriched functional properties and microbial composition may subsequently benefit the plant's health and tolerance to HLB disease. Overall, this study advances our understanding of the important role of root-associated microbiota changes and ecological factors, such as soil acidity, in delaying and alleviating HLB disease.

Comparative Proteomic Analysis of Sweet Orange Petiole Provides Insights Into the Development of Huanglongbing Symptoms.

Huanglongbing (HLB) is the most destructive citrus disease worldwide. This is associated with the phloem-limited bacterium Candidatus Liberibacter, and the typical symptom is leaf blotchy mottle. To better understand the biological processes involved in the establishment of HLB disease symptoms, the comparative proteomic analysis was performed to reveal the global protein accumulation profiles in leaf petiole, where there are massive HLB pathogens of Ca. L. asiaticus-infected Newhall sweet orange (Citrus sinensis) plants at the asymptomatic and symptomatic stages compared to their healthy counterpart. Photosynthesis, especially the pathway involved in the photosystem I and II light reactions, was shown to be suppressed throughout the whole Ca. L. asiaticus infection cycle. Also, starch biosynthesis was induced after the symptom-free prodromal period. Many defense-associated proteins were more extensively regulated in the petiole with the symptoms than the ones from healthy plants. The change of salicylic and jasmonic acid levels in different disease stages had a positive correlation with the abundance of phytohormone biosynthesis-related proteins. Moreover, the protein-protein interaction network analysis indicated that an F-type ATPase and an alpha-1,4 glucan phosphorylase were the core nodes in the interactions of differentially accumulated proteins. Our study indicated that the infected citrus plants probably activated the non-unified and lagging enhancement of defense responses against Ca. L. asiaticus at the expense of photosynthesis and contribute to find out the key Ca. L. asiaticus-responsive genes for tolerance and resistance breeding.

Complete Genome Sequence Data of Xenorhabdus budapestensis Strain C72, a Candidate Biological Control Agent from China.

Xenorhabdus budapestensis strain C72 isolated from the entomopathogenic nematode of Steinernema bicornutum possesses an excellent biocontrol effect on southern corn leaf blight. However, its genomic information is lacking. Here, we report a high-quality complete and annotated genome sequence of X. budapestensis strain C72. Fifteen secondary metabolite biosynthetic gene clusters are identified in the genome, which are responsible for the production of a diverse group of antimicrobial compounds to help host plants against agricultural pathogenic diseases. This genome sequence could contribute to investigations of the molecular basis underlying the biocontrol activity of this Xenorhabdus strain.

Nbnrp1 mediates Verticillium dahliae effector PevD1-triggered defense responses by regulating sesquiterpenoid phytoalexins biosynthesis pathway in Nicotiana benthamiana.

PevD1, a fungal effector secreted by Verticillium dahliae, could induce hypersensitive responses-like necrosis and systemic acquired resistance (SAR) in cotton and tobacco plants. PevD1 could drastically induce the expression of Nbnrp1, which is an asparagine-rich protein (NRP) of Nicotiana benthamiana. Our previous research indicated that Nbnrp1 positively regulated PevD1-induced cell necrosis and disease resistance. In this study, we further investigated PevD1-induced immune responses in both wild-type (WT) and Nbnrp1-RNAi lines through RNA-seq, in order to reveal the underlying mechanism of Nbnrp1-modulated PevD1-induced disease resistance in N. benthamiana. Results showed that Nbnrp1-RNAi lines exhibited reduced PevD1-induced immune responses, like inhibiting H2O2 accumulation and MAPK phosphorylation. To silence Nbnrp1 inhibited the expression of PevD1-induced differential expression genes (DEGs) involved in pathways associated with sesquiterpenoid and triterpenoid biosynthesis, flavone and flavonol biosynthesis, plant-pathogen interaction and phenylpropanoid biosynthesis, etc. It is worth noting that sesquiterpene phytoalexin capsidiol accumulation were obviously decreased in Nbnrp1-RNAi plants after PevD1 treatment, accompanied with the down-expression of EAS and EAH, which were two key genes related to capsidiol biosynthesis. These results suggested that Nbnrp1 mediates PevD1-induced defense responses by regulating sesquiterpenoid phytoalexins biosynthesis pathway.

Sub-Lethal Effects of Partially Purified Protein Extracted from Beauveria bassiana (Balsamo) and Its Presumptive Role in Tomato (Lycopersicon esculentum L.) Defense against Whitefly (Bemisia tabaci Genn.).

Plants rely on various physiological and molecular defense mechanisms against biotic stresses such as herbivore insects. Many entomopathogenic fungi synthesize protein molecules that can trigger these plant defenses. This laboratory study characterized the bioactivity of a partially purified protein derived from Beauveria bassiana (ARSEF 2860) against whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), which is an economically important pest of agricultural and horticultural crops worldwide. Different concentrations (i.e., 0.021, 0.042 and 0.063 µM) of fungal protein were bioassayed to determine their sub-lethal effect on the survival percentage and fecundity rate of B. tabaci on tomato (Lycopersicon esculentum) plants. In addition, the putative role of this partially purified B. bassiana protein in the defense mechanisms of plant was assessed through the expression analyses of important genes related to salicylic acid (SA)-and jasmonic acid (JA)-associated pathways using RT-qPCR. Results revealed a significant suppression of the survival percentage and fecundity rate of B. tabaci by the fungal protein. Lowest survival (41%) was recorded for the highest concentration of protein (0.063 µM), whereas mean survival for the other two protein concentrations (0.042 and 0.021 µM) were 62 and 71%, respectively. Likewise, the highest and lowest mean fecundity rates were observed for the control and the highest protein concentration (i.e., 3.3 and 1.8 eggs day-1 female-1, respectively). Furthermore, the exogenous application of B. bassiana-derived protein on tomato plants strongly up-regulated the SA-related genes (PAL, PR1, BGL2 and EDS1) and slightly up-regulated the JA-related genes (AOC, AOS, OPR3 and LOX) as compared to the control plants. These findings demonstrate the putative role of this partially purified B. bassiana protein fraction in inducing systemic resistance in the tomato plants against B. tabaci, suggesting its further purification and characterization to be used as novel biological pest control tool against B. tabaci and other sap-sucking insect pests.

Identification and Functional Analysis of AopN, an Acidovorax Citrulli Effector that Induces Programmed Cell Death in Plants.

Bacterial fruit blotch (BFB), caused by Acidovorax citrulli, seriously affects watermelon and other cucurbit crops, resulting in significant economic losses. However, the pathogenicity mechanism of A. citrulli is not well understood. Plant pathogenic bacteria often suppress the plant immune response by secreting effector proteins. Thus, identifying A. citrulli effector proteins and determining their functions may improve our understanding of the underlying pathogenetic mechanisms. In this study, a novel effector, AopN, which is localized on the cell membrane of Nicotiana benthamiana, was identified. The functional analysis revealed that AopN significantly inhibited the flg22-induced reactive oxygen species burst. AopN induced a programmed cell death (PCD) response. Unlike its homologous protein, the ability of AopN to induce PCD was dependent on two motifs of unknown functions (including DUP4129 and Cpta_toxin), but was not dependent on LXXLL domain. More importantly, the virulence of the aopN mutant of A. citrulli in N. benthamiana significantly decreased, indicating that it was a core effector. Further analysis revealed that AopN interacted with watermelon ClHIPP and ClLTP, which responds to A. citrulli strain Aac5 infection at the transcription level. Collectively, these findings indicate that AopN suppresses plant immunity and activates the effector-triggered immunity pathway.

Biocontrol Potential of Purified Elicitor Protein PeBL1 Extracted from Brevibacillus laterosporus Strain A60 and Its Capacity in the Induction of Defense Process against Cucumber Aphid (Myzus persicae) in Cucumber (Cucumis sativus).

The Cucumber aphid (Myzus persicae), a destructive cucumber aphid usually managed by chemical pesticides, is responsible for enormous annual agricultural losses. A protein elicitor, PeBL1, was investigated in the present work for its ability to induce a defense response against M. persicae in cucumber. The rates of population growth (Intrinsic rate of increase) of M. persicae (second and third generations) decreased with PeBL1-treated cucumber seedlings as compared to positive (water) and negative 70.58 µg mL-1 controls (50 mM Tris-HCl, pH 8.0). In an assay on host selection, M. persicae had a preference for colonizing control plants as compared to the PeBL1-treated cucumber seedlings. The nymphal development time of the aphid was extended with the PeBL1-treated cucumber seedlings. Likewise, fecundity was reduced, with less offspring produced in the PeBL1-treated cucumber seedlings as compared to the positive (water) and negative 70.58 µg mL-1 controls (50 mM Tris-HCl, pH 8.0). The cucumber leaves treated with PeBL1 had a hazardous surface environment for M. persicae, caused by trichomes and wax formation. Jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) levels were significantly higher, exhibiting significant accumulation in the PeBL1-treated cucumber seedlings. The following results showed that PeBL1 considerably altered the height of the cucumber plant and the surface structure of the leaves to minimize M. persicae reproduction, and it prevented colonization. Defensive processes also included the activation of pathways (JA, SA, and ET). This study provides evidence of biocontrol for the use of PeBL1 in cucumber defense against M. persicae.

Acid Soil Improvement Enhances Disease Tolerance in Citrus Infected by Candidatus Liberibacter asiaticus.

Huanglongbing (HLB) is a devastating citrus disease that has caused massive economic losses to the citrus industry worldwide. The disease is endemic in most citrus-producing areas of southern China, especially in the sweet orange orchards where soil acidification has intensified. In this work, we used lime as soil pH amendment to optimize soil pH and enhance the endurance capacity of citrus against Candidatus Liberibacter asiaticus (CLas). The results showed that regulation of soil acidity is effective to reduce the occurrence of new infections and mitigate disease severity in the presence of HLB disease. We also studied the associated molecular mechanism and found that acid soil improvement can (i) increase the root metabolic activity and up-regulate the expression of ion transporter-related genes in HLB-infected roots, (ii) alleviate the physiological disorders of sieve tube blockage of HLB-infected leaves, (iii) strengthen the citrus immune response by increasing the expression of genes involved in SAR and activating the salicylic acid signal pathway, (iv) up-regulate 55 proteins related to stress/defence response and secondary metabolism. This study contributes to a better understanding of the correlation between environment factors and HLB disease outbreaks and also suggests that acid soil improvement is of potential value for the management of HLB disease in southern China.

A tripartite ssDNA mycovirus from a plant pathogenic fungus is infectious as cloned DNA and purified virions.

Here, we describe a tripartite circular single-stranded (ss) DNA mycovirus, named Fusarium graminearum gemytripvirus 1 (FgGMTV1). The genome of FgGMTV1 comprises three circular ssDNA segments (DNA-A, DNA-B, and DNA-C). Sequence alignments and phylogenetic analyses showed that FgGMTV1 is nested within the family Genomoviridae. We also constructed the first infectious DNA clones of a DNA mycovirus. Our results show that DNA-A and DNA-B are mutually interdependent for their replication and are associated with severely reduced colony growth and hypovirulence. DNA-C relies on DNA-A and DNA-B for replication and is necessary for the recovery of abnormal fungal phenotypes. DNA-C also enhances the accumulation of viral DNA in infected fungi and permits stable colonization and easy transmission via conidia. This is the first multipartite DNA virus isolated from a fungus. Our phylogenetic analyses also suggest that the multipartite genome of FgGMTV1 may have evolved from a monopartite genome of an ancient genomovirus.

Putative Role of a Yet Uncharacterized Protein Elicitor PeBb1 Derived from Beauveria bassiana ARSEF 2860 Strain against Myzus persicae (Homoptera: Aphididae) in Brassica rapa ssp. pekinensis.

This study reports the characterization of protein elicitor PeBb1 derived from entomopathogenic fungus Beauveria bassiana ARSEF-2860 strain and its putative role in induced systemic resistance in Brassica rapa ssp. pekinensis against green peach aphid Myzus persicae. The sequence of purified elicitor protein was matched with the genomic sequence of a hypothetical protein BBA_10269 from B. bassiana ARSEF-2860 (GenBank Accession No. XP_008603588.1). The protein-encoding gene PeBb1 contained 534 bp cDNA encoding a polypeptide of 177 amino acids with a molecular mass of 19 kDa. The recombinant elicitor protein was expressed in Escherichia coli using pET-28a (+) expression vector and induced necrosis in the leaves of tobacco. The effects of elicitor protein on aphid M. persicae was determined by applying three different concentrations of PeBb1 (i.e., 26, 35, 53 µM) on B. rapa plants at 4-leaf stage and the treated plants were exposed to newly emerged (0-6 h old) apterous adult aphids. Bioassay results showed significant (p < 0.05) sub-lethal effects of the exogenous application of PeBb1 elicitor on M. persicae. Moreover, the RT-qPCR gene expression analyses showed a significant up-regulation of most of the key genes linked to ethylene (ET)- and jasmonic acid (JA)-associated plant defense pathways in elicitor-treated plants. These results not only recommend the putative utilization of PeBb1 elicitor protein in future biological pest control strategies against phloem-feeding insect pests such as M. persicae, but also help in better comprehension of the mechanisms through which beneficial fungi trigger the induced plant resistance.

Protein Elicitor PeBL1 of Brevibacillus laterosporus Enhances Resistance Against Myzus persicae in Tomato.

Myzus persicae, a destructive aphid of tomato usually managed by chemical pesticides, is responsible for huge annual losses in agriculture. In the current work, a protein elicitor, PeBL1, was investigated for its capacity to induce a defense response against M. persicae in tomato. Population growth rates of M. persicae (second and third generation) decreased with PeBL1 treatments as compared with controls. In a host selection assay, M. persicae showed preference for colonizing control plants as compared to tomato seedlings treated with PeBL1. Tomato leaves treated with PeBL1 gave rise to a hazardous surface environment for M. persicae due to formation of trichomes and wax. Jasmonic acid (JA), salicylic acid (SA), and ethylene (ET) showed significant accumulation in tomato seedlings treated by PeBL1. The following results showed that PeBL1 significantly modified the tomato leaf surface structure to reduce reproduction and deter colonization by M. persicae. Defense processes also included activation of JA, SA, and ET pathways. The study provides evidence for use of PeBL1 in the protection of tomato from M. persicae.

Protein elicitor PeaT1 enhanced resistance against aphid (Sitobion avenae) in wheat.

BACKGROUND: Sitobion avenae, a dominant aphid in wheat that causes huge annual losses in agriculture, is mainly controlled using chemical pesticides. In this study, we investigated a protein elicitor, PeaT, for its induction of the defense response in wheat against Sitobion avenae. RESULTS: Intrinsic rates of increase in second and third generations of S. avenae decreased in the PeaT1 (second generation 0.31 ± 0.01, third generation 0.28 ± 0.01) treatment compared with controls (second generation 0.28 ± 0.01, third generation 0.26 ± 0.01). S. avenae preferred to colonize control rather than PeaT1-treated wheat seedlings in a host selection test. PeaT1-treated wheat leaves possessed more trichomes and wax that formed a disadvantageous surface environment for S. avenae. Both salicylic acid (SA) and jasmonic acid (JA) accumulated significantly in PeaT1-treated wheat seedlings. CONCLUSION: These results showed that PeaT1 modified physical surface structures in wheat to reduce reproduction and deter colonization by S. avenae. SA and JA were involved in the induced physical defense process. This study provided evidence for use of PeaT1 as a 'vaccine' to protect wheat from Sitobion avenae. © 2019 Society of Chemical Industry.

Anti-insect activity of a partially purified protein derived from the entomopathogenic fungus Lecanicillium lecanii (Zimmermann) and its putative role in a tomato defense mechanism against green peach aphid.

Many biotrophic and necrotrophic fungi synthesize proteins that may elicit induced plant resistance against different herbivore pests. This in-vitro study elucidates the sub-lethal effect of a partially-purified protein derived from the entomopathogenic fungus Lecanicillium lecanii (Zimmerman) (Hypocreales: Clavicipitaceae) against green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae), an economically important pest of many solanaceous crops including tomato. Bioassays were conducted to determine the impact of different concentrations of protein (i.e. 0.018, 0.036 and 0.054 µM) on the survival and fecundity of M. persicae on tomato (Lycopersicon esculentum) plants. Moreover, the potential role of this exogenous protein in the plant defense mechanism was assessed by expression analyses of key genes associated with salicylic acid (SA) and jasmonic acid (JA) pathways using RT-qPCR. The results indicated a significant negative effect of all protein concentrations on the survivorship and fecundity of M. persicae. The highest concentration (0.054 µM) resulted in lowest survival (46%) of aphids at 7th day post-treatment, while two other concentrations (0.036 and 0.018 µM) resulted in 61 and 71% survival rate, respectively. Similarly, lowest and highest mean fecundity rates were recorded for the highest protein concentration and the control (1.5 and 2.4 nymphs day-1 female-1), respectively. Moreover, L. lecanii-derived protein strongly upregulated the SA associated genes PR1, BGL2 and PAL, and moderately upregulated the JA associated genes LOX, AOS and AOC in protein-treated tomato plants compared to the control plants. These findings demonstrate the systemic resistance induced in tomato plants against M. persicae by the exogenous application of partially-purified protein extracted from L. lecanii, suggesting its further purification and characterization as a novel biological pest management tool against aphids and other phloem-feeding insect pests.

A Novel Protein Elicitor PeBL2, from Brevibacillus laterosporus A60, Induces Systemic Resistance against Botrytis cinerea in Tobacco Plant.

Here, we reported a novel secreted protein elicitor PeBL2 from Brevibacillus laterosporus A60, which can induce hypersensitive response in tobacco (Nicotiana benthamiana). The ion-exchange chromatography, high-performance liquid chromatography (HPLC) and mass spectrometry were performed for identification of protein elicitor. The 471 bp PeBL2 gene produces a 17.22 kDa protein with 156 amino acids containing an 84-residue signal peptide. Consistent with endogenous protein, the recombinant protein expressed in Escherichia coli induced the typical hypersensitive response (HR) and necrosis in tobacco leaves. Additionally, PeBL2 also triggered early defensive response of generation of reactive oxygen species (H2O2 and O2 -) and systemic resistance against of B. cinerea. Our findings shed new light on a novel strategy for biocontrol using B. laterosporus A60.