A Methyl Esterase 1 (PvMES1) Promotes the Salicylic Acid Pathway and Enhances Fusarium Wilt Resistance in Common Beans

Common bean (Phaseolus vulgaris L.) is an important food legume. Fusarium wilt caused by Fusarium oxysporum f. sp. phaseoli is one of the most serious soil-born diseases of common bean found throughout the world and affects the yield and quality of the crop. Few sources of Fusarium wilt resistance exist in legumes and most are of quantitative inheritance. In this study, we have identified a methyl salicylate esterase (MES), PvMES1, that contributes to plant defense response by regulating the salicylic acid (SA) mediated signaling pathway in response to Fusarium wilt in common beans. The result showed the role of PvMES1 in regulating SA levels in common bean and thus the SA signaling pathway and defense response mechanism in the plant. Overexpression of the PvMES1 gene enhanced Fusarium wilt resistance; while silencing of the gene caused susceptibility to the diseases. RNA-seq analysis with these transiently modified plants showed that genes related to SA level changes included the following gene ontologies: a) interaction between host and pathogen; b) phenylpropanoid synthesis; and c) sugar metabolism as well as others. These key signal elements activated the defense response pathway in common bean to Fusarium wilt. Collectively, our findings indicate that PvMES1 plays a pivotal role in regulating SA biosynthesis and signaling, and increasing Fusarium wilt resistance in common bean, thus providing novel insight into the practical applications of both SA and MES genes and pathways they contribiute to for developing elite crop varieties with enhanced broad-spectrum resistance to this critical disease

Genome-wide identification of the TGA genes in common bean (Phaseolus vulgaris) and revealing their functions in response to Fusarium oxysporum f. sp. phaseoli infection

Fusarium wilt, which affects common bean all across the world, is caused by Fusarium oxysporum f. sp. Phaseoli (Fop). It is necessary to have functional genes in response to Fop infection because they might be used to manage disease. As a crucial regulator, TGA-binding transcription factor (TGA) is engaged in the defense mechanism of plants against pathogens. The role of TGA regulators in common bean in response to Fop infection, however, has not been documented. Hence, we performed genome-wide identified and characterized eight TGA genes in common bean. In this study, eight PvTGA genes were distributed on six chromosomes and classified into four subgroups. The PvTGA genes have the same conserved bZIP and DOG1 domains, but there are specific sequence structures in different PvTGAs. Phylogenetic and synteny analysis explained that PvTGA gene has a close genetic relationship with legume TGAs and that PvTGA03 and PvTGA05 may play an important role in evolution. Transcriptome data explained that expression levels of PvTGA genes showed diversity in different tissues. After Fop inoculation, the expression levels of PvTGA03 and PvTGA07 were significantly different between resistant and susceptible genotypes. Under SA treatment, the expression levels of PvTGA03, PvTGA04, PvTGA06, PvTGA07 and PvTGA08 were significantly different. These results imply that PvTGA03 and PvTGA07 play key roles in SA-mediated resistance to Fusarium wilt. Together, these findings advance knowledge of the PvTGA gene family in common bean and will help future studies aimed at reducing Fusarium wilt

Hairy root transgene expression analysis of a secretory peroxidase (PvPOX1) from common bean infected by Fusarium wilt

Plant peroxidases (POXs) are one of the most important redox enzymes in the defense responses. However, the large number of different plant POX genes makes it necessary to carefully confirm the function of each paralogous POX gene in specific tissues and disease interactions. Fusarium wilt is a devastating disease of common bean caused by Fusarium oxysporum f. sp. phaseoli. In this study, we evaluated a peroxidase gene, PvPOX1, from a resistant common bean genotype, CAAS260205 and provided direct evidence for PvPOX1’s role in resistance by transforming the resistant allele into a susceptible common bean genotype, BRB130, via hairy root transformation using Agrobacterium rhizogenes. Analysis of PvPOX1 gene over-expressing hairy roots showed it increased resistance to Fusarium wilt both in the roots and the rest of transgenic plants. Meanwhile, the PvPOX1 expressive level, the peroxidase activity and hydrogen peroxide (H2O2) accumulation were also enhanced in the interaction. The result showed that the PvPOX1 gene played an essential role in Fusarium wilt resistance through the occurrence of reactive oxygen species (ROS) induced hypersensitive response. Therefore, PvPOX1 expression was proven to be a valuable gene for further analysis which can strengthen host defense response against Fusarium wilt through a ROS activated resistance mechanism

Genome-wide analysis reveals regulatory mechanisms and expression patterns of TGA genes in peanut under abiotic stress and hormone treatments

IntroductionThe TGA transcription factors, plays a crucial role in regulating gene expression. In cultivated peanut (Arachis hypogaea), which faces abiotic stress challenges, understanding the role of TGAs is important.MethodsIn this study, we conducted a comprehensive in analysis of the TGA gene family in peanut to elucidate their regulatory mechanisms and expression patterns under abiotic stress and hormone treatments. Furthermore, functional studies on the representative AhTGA gene in peanut cultivars were conducted using transgenic Arabidopsis and soybean hair roots.ResultsThe genome-wide analysis revealed that a total of 20 AhTGA genes were identified and classified into five subfamilies. Collinearity analysis revealed that AhTGA genes lack tandem duplication, and their amplification in the cultivated peanut genome primarily relies on the whole-genome duplication of the diploid wild peanut to form tetraploid cultivated peanut, as well as segment duplication between the A and B subgenomes. Promoter and Protein-protein interaction analysis identified a wide range of cis-acting elements and potential interacting proteins associated with growth and development, hormones, and stress responses. Expression patterns of AhTGA genes in different tissues, under abiotic stress conditions for low temperature and drought, and in response to hormonal stimuli revealed that seven AhTGA genes from groups I (AhTGA04, AhTGA14 and AhTGA20) and II (AhTGA07, AhTGA11, AhTGA16 and AhTGA18) are involved in the response to abiotic stress and hormonal stimuli. The hormone treatment results indicate that these AhTGA genes primarily respond to the regulation of jasmonic acid and salicylic acid. Overexpressing AhTGA11 in Arabidopsis enhances resistance to cold and drought stress by increasing antioxidant activities and altering endogenous hormone levels, particularly ABA, SA and JA.DiscussionThe AhTGA genes plays a crucial role in hormone regulation and stress response during peanut growth and development. The findings provide insights into peanut's abiotic stress tolerance mechanisms and pave the way for future functional studies

Design and Evaluation of FBG-Based Tension Sensor in Laparoscope Surgical Robots

Due to the narrow space and a harsh chemical environment in the sterilization processes for the end-effector of surgical robots, it is difficult to install and integrate suitable sensors for the purpose of effective and precise force control. This paper presents an innovative tension sensor for estimation of grasping force in our laparoscope surgical robot. The proposed sensor measures the tension of cable using fiber gratings (FBGs) which are pasted in the grooves on the inclined cantilevers of the sensor. By exploiting the stain measurement characteristics of FBGs, the small deformation of the inclined cantilevers caused by the cable tension can be measured. The working principle and the sensor model are analyzed. Based on the sensor model, the dimensions of the sensor are designed and optimized. A dedicated experimental setup is established to calibrate and test the sensor. The results of experiments for estimation the grasping force validate the sensor

Differentially Expressed Genes in Resistant and Susceptible Common Bean (Phaseolus vulgaris L.) Genotypes in Response to Fusarium oxysporum f. sp. phaseoli

Fusarium wilt of common bean (Phaseolus vulgaris L.), caused by Fusarium oxysporum Schlechtend.:Fr. f.sp. phaseoli (Fop), is one of the most important diseases of common beans worldwide. Few natural sources of resistance to Fop exist and provide only moderate or partial levels of protection. Despite the economic importance of the disease across multiple crops, only a few of Fop induced genes have been analyzed in legumes. Therefore, our goal was to identify transcriptionally regulated genes during an incompatible interaction between common bean and the Fop pathogen using the cDNA amplified fragment length polymorphism (cDNA-AFLP) technique. We generated a total of 8,730 transcript-derived fragments (TDFs) with 768 primer pairs based on the comparison of a moderately resistant and a susceptible genotype. In total, 423 TDFs (4.9%) displayed altered expression patterns after inoculation with Fop inoculum. We obtained full amplicon sequences for 122 selected TDFs, of which 98 were identified as annotated known genes in different functional categories based on their putative functions, 10 were predicted but non-annotated genes and 14 were not homologous to any known genes. The 98 TDFs encoding genes of known putative function were classified as related to metabolism (22), signal transduction (21), protein synthesis and processing (20), development and cytoskeletal organization (12), transport of proteins (7), gene expression and RNA metabolism (4), redox reactions (4), defense and stress responses (3), energy metabolism (3), and hormone responses (2). Based on the analyses of homology, 19 TDFs from different functional categories were chosen for expression analysis using quantitative RT-PCR. The genes found to be important here were implicated at various steps of pathogen infection and will allow a better understanding of the mechanisms of defense and resistance to Fop and similar pathogens. The differential response genes discovered here could also be used as molecular markers in association mapping or QTL analysis

Differentially Expressed Genes in Resistant and Susceptible Common Bean (<i>Phaseolus vulgaris</i> L.) Genotypes in Response to <i>Fusarium oxysporum</i> f. sp. <i>phaseoli</i>

<div><p>Fusarium wilt of common bean (<i>Phaseolus vulgaris</i> L.), caused by <i>Fusarium oxysporum</i> Schlechtend.:Fr. f.sp. <i>phaseoli (Fop)</i>, is one of the most important diseases of common beans worldwide. Few natural sources of resistance to <i>Fop</i> exist and provide only moderate or partial levels of protection. Despite the economic importance of the disease across multiple crops, only a few of <i>Fop</i> induced genes have been analyzed in legumes. Therefore, our goal was to identify transcriptionally regulated genes during an incompatible interaction between common bean and the <i>Fop</i> pathogen using the cDNA amplified fragment length polymorphism (cDNA-AFLP) technique. We generated a total of 8,730 transcript-derived fragments (TDFs) with 768 primer pairs based on the comparison of a moderately resistant and a susceptible genotype. In total, 423 TDFs (4.9%) displayed altered expression patterns after inoculation with <i>Fop</i> inoculum. We obtained full amplicon sequences for 122 selected TDFs, of which 98 were identified as annotated known genes in different functional categories based on their putative functions, 10 were predicted but non-annotated genes and 14 were not homologous to any known genes. The 98 TDFs encoding genes of known putative function were classified as related to metabolism (22), signal transduction (21), protein synthesis and processing (20), development and cytoskeletal organization (12), transport of proteins (7), gene expression and RNA metabolism (4), redox reactions (4), defense and stress responses (3), energy metabolism (3), and hormone responses (2). Based on the analyses of homology, 19 TDFs from different functional categories were chosen for expression analysis using quantitative RT-PCR. The genes found to be important here were implicated at various steps of pathogen infection and will allow a better understanding of the mechanisms of defense and resistance to <i>Fop</i> and similar pathogens. The differential response genes discovered here could also be used as molecular markers in association mapping or QTL analysis.</p></div

Disease severity of common bean genotypes BRB130 (susceptible, S) and CAAS260205 (resistant, R) to Fusarium wilt (<i>F</i>. <i>oxysporum</i> f. sp. <i>phaseoli</i>).

<p>A-E show the BRB130 phenotype at 0, 4, 8, 12 and 16 d post inoculation; F-J show the CAAS260205 phenotype at 0, 4, 8, 12 and 16 d post inoculation (dpi). White arrows indicate symptoms of the susceptible reaction including (i) root reddening; (ii) hypocotyl browning; (iii) leaf chlorosis; (iv) stem and leaf wilting.</p

Defense responses in the roots of susceptible genotype BRB130 and resistant genotype CAAS260205 common bean seedlings inoculated with <i>Fusarium oxysporum</i> f. sp. <i>phaseoli</i> versus roots of non-inoculated (control) seedlings at 0, 24, 48, 72, 96 and 120 h post-inoculation.

<p>A: POX activities; B: PAL activities; C: H₂O₂ accumulation; D: O₂^- accumulation. Results from three repeated experiments are displayed. Bars indicated the standard deviations (± SD). Probability values between the control and treated plants were estimated by the Student’s <i>t</i> test, with significant difference at *<i>P</i>0.05 and **<i>P</i>0.01.</p