• Title/Summary/Keyword: plant pathogenesis

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Isolation and Differential Expression of an Acidic PR-1 cDNA Gene from Soybean Hypocotyls Infected with Phtophthora sojae f. sp. glycines

  • Kim, Choong-Seo;Yi, Seung-Youn;Lee, Yeon-Kyung;Hwang, Byung-Kook
    • The Plant Pathology Journal
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    • v.16 no.1
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    • pp.9-18
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    • 2000
  • Using differential display techniques, a new acidic pathogenesis-related (PR) protein-1 cDNA (GMPRla) gene was isolated from a cDNA library of soybean (Glycinemax L.Merr, cultivar Jangyup) hypocotyls infected by Phytophthora sojae f. sp. glycines. The 741 bp of fulllength GMPRla clone contains an open reading frame of 525 nucleotides encoding 174 amino acid residues (pI 4.23) with a putative signal peptide of 27 amino acids in the N-terminus. Predicted molecular weight of the protein is 18,767 Da. The deduced amino acid sequence of GMPRla has a high level of identity with PR-1 proteins from Brassica napus, Nicotiana tabacum, and Sambucus nigra. The GMPRla mRNA was more strongly expressed in the incompatible than the compatible interaction. The transcript accumulation was induced in the soybbean hypocotyls by treatment with ethephon or DL-$\beta$-amino-n-butyric acid, but not by wounding. In situ hybridization data showed that GMPRIa mRNAs were usually localized in the vascular bundle of hypocotyl tissues, especially phloem tissue. Differences between compatible and incompatible interactions in the timing of GMPRla mRNA accumulation were remarkable, but the spatial distribution of GMPRla mRNA was similar in both interactions. However, more GMPRla mRNA was accumulated in soybean hypocotyls at 6 and 24 h after inoculation.

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Functional Characterization of PR-1 Protein, β-1,3-Glucanase and Chitinase Genes During Defense Response to Biotic and Abiotic Stresses in Capsicum annuum

  • Hong, Jeum-Kyu;Hwang, Byung-Kook
    • The Plant Pathology Journal
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    • v.21 no.3
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    • pp.195-206
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    • 2005
  • Spatial and temporal expression of pathogenesis-related (PR) gene and proteins has been recognized as inducible defense response in pepper plants. Gene expression and/or protein accumulation of PR-1, $\beta-1,3-glucanase$ and chitinase was predominantly found in pepper plants during the inoculations by Xanthomonas campestris pv. vesicatoria, Phytophthora capsici and Colletotrichum coccodes. PR-1 and chitinase genes were also induced in pepper plants in response to environmental stresses, such as high salinity and drought. PR-1 and chitinase gene expressions by biotic and abiotic stresses were regulated by their own promoter regions containing several stress-related cis-acting elements. Overexpression of pepper PR-1 or chitinase genes in heterogeneous transgenic plants showed enhanced disease resistance as well as environmental stress tolerances. In this review, we focused on the putative function of pepper PR-1, $\beta-1,3-glucanase$ and chitinase proteins and/or genes at the biochemical, molecular and cytological aspects.

Functional Analysis of BCTV ORF L4 by Site-directed Mutagenesis (Site-directed mutagenesis를 이용한 BCTV ORF L4의 기능 분석)

  • 박을용;이석찬
    • Korean Journal Plant Pathology
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    • v.14 no.5
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    • pp.513-518
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    • 1998
  • Beet curly top virus (BCTV) mutant has been constructed in vitro that contain G-to-T transversions at nucleotide 2727 within overlapping open reading frames (ORFs) L1 and L4. The mutations introduce termination codon in ORF L4 without affecting the amino acid encoded by ORF L1. When agroinoculated into Arabidopsis thaliana the mutant caused mild stunting and stem curling, but not the callus induction and hyperlasia on infected tissues of Sei-O ecotype. However, this mutant was not infectious on Col-O. Levels of single stranded DNA forms were similar in mutant and wild type BCTV infections. The DNA quantitation data showed that the DNA of BCTV-L4 mutant virus was accumulated in shoot tips, infection origin and roots with similar levels to those of wild type virus infected. Three tissues of asymptomatic ecotype Col-O also had as much as virus DNA from wild type virus infections. In both ecotypes infected with BCTV-Logan and BCTV-L4 mutant, root tissues contained more virus DNA than any other tissues by the Southern hybridization data. The results suggest that ORF L4 encodes a functional protein that is a major determinant of pathogenesis that might affect the hyperplastic response of the host to BCTV infection.

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Water Extract from Spent Mushroom Substrate of Hericium erinaceus Suppresses Bacterial Wilt Disease of Tomato

  • Kwak, A Min;Min, Kyeong Jin;Lee, Sang Yeop;Kang, Hee Wan
    • Mycobiology
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    • v.43 no.3
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    • pp.311-318
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    • 2015
  • Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding ${\beta}$-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction.

GzRUM1, Encoding an Ortholog of Human Retinoblastoma Binding Protein 2, is Required for Ascospore Development in Gibberella zeae

  • Kim, Hee-Kyoung;Lee, Yin-Won;Yun, Sung-Hwan
    • The Plant Pathology Journal
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    • v.27 no.1
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    • pp.20-25
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    • 2011
  • Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

Population Structure of Fusarium graminearum from Maize and Rice in 2009 in Korea

  • Lee, Seung-Ho;Lee, Jung-Kwan;Nam, Young-Ju;Lee, Soo-Hyung;Ryu, Jae-Gee;Lee, Theresa
    • The Plant Pathology Journal
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    • v.26 no.4
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    • pp.321-327
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    • 2010
  • We performed diagnostic PCR assays and a phylogenetic analysis using partial sequences of TEF1 (translation elongation factor-1) to determine the trichothecene chemotypes and genetic diversity of F. graminearum isolates from maize and rice samples collected in 2009 in Korea. PCR using a species-specific primer set revealed a total of 324 isolates belonging to the putative F. graminearum species complex. PCR with trichothecene chemotypespecific primers revealed that the nivalenol (NIV) chemotype was predominant among the fungal isolates from rice (95%) in all provinces examined. In contrast, the predominant chemotype among the corn isolates varied according to region. The deoxynivalenol (DON) chemotype was found more frequently (66%) than the NIV chemotype in Gangwon Province, whereas the NIV chemotype (70%) was predominant in Chungbuk Province. Phylogenetic analysis showed that all DON isolates examined were clustered into lineage 7, while the NIV isolates resided within lineage 6 (F. asiaticum). Compared with previous studies, the lineage 6 isolates in rice have been predominantly maintained in southern provinces, while the dominance of lineage 7 in maize has been evident in Gangwon at a slightly reduced level.

Inhibitory Activity of Sedum middendorffianum-Derived 4-Hydroxybenzoic Acid and Vanillic Acid on the Type III Secretion System of Pseudomonas syringae pv. tomato DC3000

  • Kang, Ji Eun;Jeon, Byeong Jun;Park, Min Young;Kim, Beom Seok
    • The Plant Pathology Journal
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    • v.36 no.6
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    • pp.608-617
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    • 2020
  • The type III secretion system (T3SS) is a key virulence determinant in the infection process of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Pathogen constructs a type III apparatus to translocate effector proteins into host cells, which have various roles in pathogenesis. 4-Hydroxybenozic acid and vanillic acid were identified from root extract of Sedum middendorffianum to have inhibitory effect on promoter activity of hrpA gene encoding the structural protein of the T3SS apparatus. The phenolic acids at 2.5 mM significantly suppressed the expression of hopP1, hrpA, and hrpL in the hrp/hrc gene cluster without growth retardation of Pst DC3000. Auto-agglutination of Pst DC3000 cells, which is induced by T3SS, was impaired by the treatment of 4-hydroxybenzoic acid and vanillic acid. Additionally, 2.5 mM of each two phenolic acids attenuated disease symptoms including chlorosis surrounding bacterial specks on tomato leaves. Our results suggest that 4-hydroxybenzoic acid and vanillic acid are potential anti-virulence agents suppressing T3SS of Pst DC3000 for the control of bacterial diseases.

Ligustrum lucidum Fruits Extract Inhibits Acute Pulmonary Inflammation in Mice (생쥐에서 급성 폐렴에 대한 여정자 열매 추출물의 억제효과)

  • Kwak, Ho Geun;Lim, Heung-Bin
    • Korean Journal of Medicinal Crop Science
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    • v.21 no.5
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    • pp.323-328
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    • 2013
  • Traditionally, Ligustrum lucidum fruits (LL) is one of the well-known oriental herb used in the treatment of skin and lung inflammation. This study investigated anti-inflammatory effects of LL in the pathogenesis of acute pulmonary inflammation in mice. Acute pulmonary inflammation was induced by intratracheal instillation of cigarette smoke condensate (CSC) and lipopolysaccharide (LPS) 5 times within 12 days in mice. LL extract was administered orally at a dose of 50 or 200 mg/kg. Administration of LPS and CSC significantly elevated airway hyperresponsiveness (AHR) to mice, and increased in the levels of inflammatory cells and mediators in mice. However, the LL extract significantly reduced the elevated AHR, and the increase of neutrophils, $CD4^+/CD3^+$ cells and $CD8^+/CD3^+$ cells, along with reducing the expression of TNF-${\alpha}$, IL-6, and MIP-2. Moreover, the LL extract alleviated the infiltration of inflammatory cells in expanded airway walls histologically. These results indicate that the LL extract has an inhibitory effects on acute pulmonary inflammation and AHR in murine model, and plays a crucial role as a immunomodulator which possess anti-inflammatory property.

Interaction between Dietary Factors and Gut Microbiota in Ulcerative Colitis (궤양성 대장염에서 식이 인자와 장 마이크로비오타의 상호작용)

  • Mi-Kyung Sung
    • Journal of Digestive Cancer Research
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    • v.10 no.1
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    • pp.31-38
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    • 2022
  • Ulcerative colitis (UC) exhibits chronic intestinal inflammatory conditions with cycles of relapse and remission. The incidence is rapidly growing in Asian countries including South Korea possibly due to changes in lifestyles. Although the etiology of inflammatory bowel disease is inconclusive, gut microbiota composition is considered a critical factor involved in the pathogenesis of UC. The overgrowth of pathogenic bacteria evokes hyper-immune responses in gut epithelium causing tissue inflammation and damage. Also, failure to regulate gut epithelium integrity due to chronic inflammation and mucus depletion accelerates bacterial translocation aggravating immune dysregulation. Gut microbiota composition responds to the diet in a very rapid manner. Epidemiological studies have indicated that the risk of UC is associated with low plant foods/high animal foods consumption. Several bacterial strains consistently found depleted in UC patients use plant food-originated dietary fiber producing short chain fatty acids to maintain epithelial integrity. These bacteria also use mucus layer mucin to keep gut microbiota diversity. These studies partly explain the association between dietary modification of gut microbiota in UC development. Further human intervention trials are required to allow the use of specific bacterial strains in the management of UC.

Comparative Analysis of Defense Responses in Chocolate Spot-Resistant and -Susceptible Faba Bean (Vicia faba) Cultivars Following Infection by the Necrotrophic Fungus Botrytis fabae

  • El-Komy, Mahmoud H.
    • The Plant Pathology Journal
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    • v.30 no.4
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    • pp.355-366
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    • 2014
  • In this study, resistance responses were investigated during the interaction of Botrytis fabae with two faba bean cultivars expressing different levels of resistance against this pathogen, Nubaria (resistant) and Giza 40 (susceptible). Disease severity was assessed on leaves using a rating scale from 1 to 9. Accumulation levels of reactive oxygen species (ROS), lipid peroxidation and antioxidant enzymes (superoxide dismutase, catalase and ascorbate peroxidase) were measured in leaf tissues at different times of infection. The expression profiles of two pathogenesis-related proteins (PRPs) encoded by the genes PR-1 and ${\beta}$-1,3-glucanase were also investigated using reverse transcription RT-PCR analysis. The accumulation of these defense responses was induced significantly in both cultivars upon infection with B. fabae compared with un-inoculated controls. The resistant cultivar showed weaker necrotic symptom expression, less ROS accumulation, a lower rate of lipid peroxidation and higher activity of the enzymatic ROS scavenging system compared with susceptible cultivar. Interestingly, ROS accumulated rapidly in the resistant leaf tissues and peaked during the early stages of infection, whereas accumulation was stronger and more intense in the susceptible tissues in later stages. Moreover, the response of the resistant cultivar to infection was earlier and stronger, exhibiting high transcript accumulation of the PR genes. These results indicated that the induction of oxidant/antioxidant responses and the accumulation of PRPs are part of the faba bean defense mechanism against the necrotrophic fungus B. fabae with a different intensity and timing of induction, depending on the resistance levels.