Effects on Capsicum annuum Plants Colonized with Trichoderma atroviride P. Karst Strains Genetically Modified in Taswo1, a Gene Coding for a Protein with Expansin-like Activity

Here, we analyzed the effects on Capsicum annuum plants of Trichoderma atroviride P. Karst strains altered in the expression of SWOLLENIN (SWO1), a protein with amorphogenic activity on plant cell wall components. Strains of T. atroviride that overexpressed the Taswo1 gene were constructed as well as deletion mutants. A novel, cheap and accurate method for assessing root colonization was developed. Colonization assays showed that the Taswo1 overexpressing strains invaded the host root better than the WT, resulting in a stronger plant growth-promoting effect. The expression of plant defense marker genes for both the systemic acquired resistance and induced systemic resistance pathways was enhanced in plants inoculated with Taswo1 overexpressing strains, while inoculation with deletion mutant strains resulted in a similar level of expression to that observed upon inoculation with the wild-type strain. Response to pathogen infection was also enhanced in the plants inoculated with the Taswo1 overexpressing strains, and surprisingly, an intermediate level of protection was achieved with the mutant strains. Tolerance to abiotic stresses was also higher in plants inoculated with the Taswo1 overexpressing strains but was similar in plants inoculated with the wild-type or the mutant strains. Compatible osmolyte production in drought conditions was studied. This study may contribute to improving Trichoderma biocontrol and biofertilization abilities.

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Isolation and Characterization of Broad-Spectrum Disease-Resistant Arabidopsis Mutants

Genetics ◽

10.1093/genetics/160.4.1661 ◽

2002 ◽

Vol 160 (4) ◽

pp. 1661-1671

Author(s):

Klaus Maleck ◽

Urs Neuenschwander ◽

Rebecca M Cade ◽

Robert A Dietrich ◽

Jeffery L Dangl ◽

...

Keyword(s):

Pseudomonas Syringae ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Constitutive Expression ◽

Firefly Luciferase ◽

Marker Genes ◽

Arabidopsis Mutants ◽

Isolation And Characterization ◽

Firefly Luciferase Gene

Abstract To identify Arabidopsis mutants that constitutively express systemic acquired resistance (SAR), we constructed reporter lines expressing the firefly luciferase gene under the control of the SAR-inducible PR-1 promoter (PR-1/luc). After EMS mutagenesis of a well-characterized transgenic line, we screened 250,000 M2 plants for constitutive expression of the reporter gene in vivo. From a mutant collection containing several hundred putative mutants, we concentrated on 16 mutants lacking spontaneous hypersensitive response (HR) cell death. We mapped 4 of these constitutive immunity (cim) mutants to chromosome arms. Constitutive expression of disease resistance was established by analyzing responses to virulent Peronospora parasitica and Pseudomonas syringae strains, by RNA blot analysis for endogenous marker genes, and by determination of salicylic acid levels in the mutants. The variety of the cim phenotypes allowed us to define distinct steps in both the canonical SAR signaling pathway and a separate pathway for resistance to Erysiphe cichoracearum, active in only a subset of the mutants.

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Extracellular Glycanases of Rhizobium leguminosarum Are Activated on the Cell Surface by an Exopolysaccharide-Related Component

Journal of Bacteriology ◽

10.1128/jb.182.5.1304-1312.2000 ◽

2000 ◽

Vol 182 (5) ◽

pp. 1304-1312 ◽

Cited By ~ 27

Author(s):

Angeles Zorreguieta ◽

Christine Finnie ◽

J. Allan Downie

Keyword(s):

Cell Wall ◽

Agrobacterium Tumefaciens ◽

Cell Surface ◽

Rhizobium Leguminosarum ◽

Plant Cell Wall ◽

Agar Medium ◽

Wild Type ◽

Close Proximity ◽

Mutant Strains ◽

Colony Surface

ABSTRACT Rhizobium leguminosarum secretes two extracellular glycanases, PlyA and PlyB, that can degrade exopolysaccharide (EPS) and carboxymethyl cellulose (CMC), which is used as a model substrate of plant cell wall cellulose polymers. When grown on agar medium, CMC degradation occurred only directly below colonies of R. leguminosarum, suggesting that the enzymes remain attached to the bacteria. Unexpectedly, when a PlyA-PlyB-secreting colony was grown in close proximity to mutants unable to produce or secrete PlyA and PlyB, CMC degradation occurred below that part of the mutant colonies closest to the wild type. There was no CMC degradation in the region between the colonies. By growing PlyB-secreting colonies on a lawn of CMC-nondegrading mutants, we could observe a halo of CMC degradation around the colony. Using various mutant strains, we demonstrate that PlyB diffuses beyond the edge of the colony but does not degrade CMC unless it is in contact with the appropriate colony surface. PlyA appears to remain attached to the cells since no such diffusion of PlyA activity was observed. EPS defective mutants could secrete both PlyA and PlyB, but these enzymes were inactive unless they came into contact with an EPS+ strain, indicating that EPS is required for activation of PlyA and PlyB. However, we were unable to activate CMC degradation with a crude EPS fraction, indicating that activation of CMC degradation may require an intermediate in EPS biosynthesis. Transfer of PlyB to Agrobacterium tumefaciens enabled it to degrade CMC, but this was only observed if it was grown on a lawn ofR. leguminosarum. This indicates that the surface ofA. tumefaciens is inappropriate to activate CMC degradation by PlyB. Analysis of CMC degradation by other rhizobia suggests that activation of secreted glycanases by surface components may occur in other species.

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NIM1 Overexpression in Arabidopsis Potentiates Plant Disease Resistance and Results in Enhanced Effectiveness of Fungicides

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.9.1114 ◽

2001 ◽

Vol 14 (9) ◽

pp. 1114-1124 ◽

Cited By ~ 99

Author(s):

Leslie Friedrich ◽

Kay Lawton ◽

Robert Dietrich ◽

Michael Willits ◽

Rebecca Cade ◽

...

Keyword(s):

Disease Resistance ◽

Plant Disease Resistance ◽

Systemic Acquired Resistance ◽

Control Strategies ◽

Chemical Activation ◽

Acquired Resistance ◽

Wild Type ◽

Protein Levels ◽

Rapid Induction ◽

Dependent Signal

The NIM1 (for noninducible immunity, also known as NPR1) gene is required for the biological and chemical activation of systemic acquired resistance (SAR) in Arabidopsis. Overexpression of NIM1 in wild-type plants (hereafter referred to as NIM1 plants or lines) results in varying degrees of resistance to different pathogens. Experiments were performed to address the basis of the enhanced disease resistance responses seen in the NIM1 plants. The increased resistance observed in the NIM1 lines correlated with increased NIM1 protein levels and rapid induction of PR1 gene expression, a marker for SAR induction in Arabidopsis, following pathogen inoculation. Levels of salicylic acid (SA), an endogenous signaling molecule required for SAR induction, were not significantly increased compared with wild-type plants. SA was required for the enhanced resistance in NIM1 plants, however, suggesting that the effect of NIM1 overexpression is that plants are more responsive to SA or a SA-dependent signal. This hypothesis is supported by the heightened responsiveness that NIM1 lines exhibited to the SAR-inducing compound benzo(1,2,3)-thiadiazole-7-car-bothioic acid S-methyl ester. Furthermore, the increased efficacy of three fungicides was observed in the NIM1 plants, suggesting that a combination of transgenic and chemical approaches may lead to effective and durable disease-control strategies.

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Conserved structure of the NPR1 gene distal promoter isolated from a chili pepper (Capsicum annuum L.) in West Sumatera

F1000Research ◽

10.12688/f1000research.17374.1 ◽

2019 ◽

Vol 8 ◽

pp. 52

Author(s):

Jamsari Jamsari ◽

Maythesya Oktavioni ◽

Bastian Nova ◽

Ifan Aulia Candra ◽

Alfi Asben ◽

...

Keyword(s):

Capsicum Annuum ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Plant Defence ◽

Promoter Sequence ◽

Chili Pepper ◽

Reference Sequence ◽

Base Substitution ◽

Silencer Elements ◽

Distal Promoter

Background: The non-expressor of pathogenesis related gene 1 (NPR1) protein is one of the key regulators in the systemic acquired resistance plant defence system. The cis-acting elements of its distal promoter gene are characterized by salicylic acid inducing elements such as the W-box, RAV1AAT and ASF1, accompanied with enhancer and silencer elements. This study was aimed to isolate and characterize the distal promoter sequence of the NPR1 gene (PD_CbNPR1) from the chili pepper (Capsicum annuum L.) genotype Berangkai, a local genotype known to produce large yields, but is susceptible to viral infection. Elucidating its sequence structure will open a broad range of possibilities to engineer the NPR1 gene expression which is important to improve chili pepper resistant. Methods: PCR-based cloning combined with a primer walking strategy was applied in this study. The BioEdit tool was used to edit the sequence and verify sequence integrity, while homology analysis was conducted with BLASTn searching. Identification of a cis-acting element was detected by PLACE. Results: Isolation of the complete distal promoter sequence of PD_CbNPR1 produced a fragment 5,950 bp in size. BLASTn search analysis indicated that PD_CbNPR1 sequence is highly conserved (99% homology) showing only a single nucleotide polymorphism (SNP) (base substitution) compared with its reference sequence. Analysis using PLACE tools successfully identified nine cis-acting elements containing a W-box, WLE1, RAV1AAT, TATA-box, CAAT-box, GARE and GT1 with multi repeats and diverse motives, as well as enhancer and silencer elements, which is characterized by a CCAAT-box and GAGAAATT pattern, respectively. Conclusion: The distal promoter of the NPR1 gene is highly conserved, showing only one SNP caused by one base substitution event.

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Determining the Relationship Between Salicylic Acid Levels and Systemic Acquired Resistance Induction in Tobacco

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.1998.11.8.795 ◽

1998 ◽

Vol 11 (8) ◽

pp. 795-800 ◽

Cited By ~ 10

Author(s):

Michael G. Willits ◽

John A. Ryals

Keyword(s):

Salicylic Acid ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Wild Type ◽

Tobacco Plants ◽

Previous Conclusion ◽

Resistance Induction ◽

Systemic Signal ◽

The Relationship

Salicylic acid (SA) has been proposed as the systemic signal for the induction of systemic acquired resistance (SAR). It has been suggested that SA is synthesized at the site of pathogen-induced necrosis and is translocated to induce SAR in uninfected leaves. Grafting studies between wild-type tobacco plants and plants that are unable to accumulate significant amounts of SA have shown that the large increase in SA accumulation seen in inoculated leaves is not necessary for SAR induction, suggesting that SA is not the primary systemic signal. However, these studies have not addressed whether decreased levels of SA accumulation in inoculated leaves are sufficient to fully induce SAR. In this study, we have determined the relationship between free SA levels in the inoculated leaf and SAR induction in tobacco. These results support our previous conclusion that SA is not likely to be the systemic signal.

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Overexpression of a Rice NPR1 Homolog Leads to Constitutive Activation of Defense Response and Hypersensitivity to Light

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-18-0511 ◽

2005 ◽

Vol 18 (6) ◽

pp. 511-520 ◽

Cited By ~ 262

Author(s):

Mawsheng Chern ◽

Heather A. Fitzgerald ◽

Patrick E. Canlas ◽

Duroy A. Navarre ◽

Pamela C. Ronald

Keyword(s):

Systemic Acquired Resistance ◽

Environmental Changes ◽

Acquired Resistance ◽

Northern Analysis ◽

Wild Type ◽

Defense Genes ◽

Isolation And Characterization ◽

Broad Spectrum Resistance ◽

Resistance Pathway

Arabidopsis NPR1/NIM1 is a key regulator of systemic acquired resistance (SAR), which confers lasting broad-spectrum resistance. Previous reports indicate that rice has a disease-resistance pathway similar to the Arabidopsis SAR pathway. Here we report the isolation and characterization of a rice NPR1 homologue (NH1). Transgenic rice plants overexpressing NH1 (NH1ox) acquire high levels of resistance to Xanthomonas oryzae pv. oryzae. The resistance phenotype is heritable and correlates with the presence of the transgene and reduced bacterial growth. Northern analysis shows that NH1ox rice spontaneously activates defense genes, contrasting with NPR1-overexpressing Arabidopsis, where defense genes are not activated until induction. Wild-type NH1, but not a point mutant corresponding to npr1-1, interacts strongly with the rice transcription factor rTGA2.2 in yeast two-hybrid. Greenhouse-grown NH1ox plants develop lesion-mimic spots on leaves at preflowering stage although no other developmental effects are observed. However, when grown in growth chambers (GCs) under low light, NH1ox plants are dwarfed, indicating elevated sensitivity to light. The GC-grown NH1ox plants show much higher salicylic acid (SA) levels than the wild type, whereas greenhouse-grown NH1ox plants contain lower SA. These results indicate that NH1 may be involved in the regulation of SA in response to environmental changes.

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Improvement of the Fungal Biocontrol Agent Trichoderma atroviride To Enhance both Antagonism and Induction of Plant Systemic Disease Resistance

Applied and Environmental Microbiology ◽

10.1128/aem.71.7.3959-3965.2005 ◽

2005 ◽

Vol 71 (7) ◽

pp. 3959-3965 ◽

Cited By ~ 98

Author(s):

Kurt Brunner ◽

Susanne Zeilinger ◽

Rosalia Ciliento ◽

Sheridian L. Woo ◽

Matteo Lorito ◽

...

Keyword(s):

Glucose Oxidase ◽

Biocontrol Agent ◽

Systemic Disease ◽

Pythium Ultimum ◽

Biocontrol Agents ◽

Systemic Resistance ◽

Infested Soil ◽

Trichoderma Atroviride ◽

Transgenic Strain ◽

Wild Type

ABSTRACT Biocontrol agents generally do not perform well enough under field conditions to compete with chemical fungicides. We determined whether transgenic strain SJ3-4 of Trichoderma atroviride, which expresses the Aspergillus niger glucose oxidase-encoding gene, goxA, under a homologous chitinase (nag1) promoter had increased capabilities as a fungal biocontrol agent. The transgenic strain differed only slightly from the wild-type in sporulation or the growth rate. goxA expression occurred immediately after contact with the plant pathogen, and the glucose oxidase formed was secreted. SJ3-4 had significantly less N-acetylglucosaminidase and endochitinase activities than its nontransformed parent. Glucose oxidase-containing culture filtrates exhibited threefold-greater inhibition of germination of spores of Botrytis cinerea. The transgenic strain also more quickly overgrew and lysed the plant pathogens Rhizoctonia solani and Pythium ultimum. In planta, SJ3-4 had no detectable improved effect against low inoculum levels of these pathogens. Beans planted in heavily infested soil and treated with conidia of the transgenic Trichoderma strain germinated, but beans treated with wild-type spores did not germinate. SJ3-4 also was more effective in inducing systemic resistance in plants. Beans with SJ3-4 root protection were highly resistant to leaf lesions caused by the foliar pathogen B. cinerea. This work demonstrates that heterologous genes driven by pathogen-inducible promoters can increase the biocontrol and systemic resistance-inducing properties of fungal biocontrol agents, such as Trichoderma spp., and that these microbes can be used as vectors to provide plants with useful molecules (e.g., glucose oxidase) that can increase their resistance to pathogens.

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Induced systemic resistance against rice grassy stunt virus – a promising field for ecological rice production

Journal of Vietnamese Environment ◽

10.13141/jve.vol2.no1.pp48-53 ◽

2012 ◽

Vol 2 (1) ◽

pp. 48-53

Author(s):

Thanh Toan Le ◽

Van Dien Luong ◽

Thuy Nhien Thi Ngo ◽

Van Kim Pham

Keyword(s):

Oxalic Acid ◽

Systemic Acquired Resistance ◽

Plant Protection ◽

Acquired Resistance ◽

Rice Production ◽

Systemic Resistance ◽

Diseased Plant ◽

Defence Reaction ◽

Rice Plants ◽

Low Concentrations

Most rice protection methods have currently used toxic chemicals to control pathogens and pests, which leads to environment pollution. Systemic acquired resistance (SAR) taking advantage of natural defence reaction of plants could be proposed as an alternative, ecologically friendly ap-proach for plant protection. Its application into rice production could minimize the chemicals quantity used, and could contribute to the decrease of environmental pollution and the development of sustainable agriculture. The research was conducted to select the best effective chemical and method to improve the health of rice plants infected by grassy stunt disease in net-house of Cantho University. SAR chemicals were used at very low concentrations (in mM). Results showed that the height of rice plants treated with SAR chemicals was higher than that of plants untreated. Besides, the number of diseased plant was reduced and the ratio of firm grain and yield increased when plants were applied by SAR. Among them, oxalic acid was the best systemic acquired resistance. With oxalic acid, seed soaking was better than seed coating in systemic acquired resistance against rice grassy stunt disease. Hầu hết các phương pháp sản xuất lúa hiện nay đều sử dụng các hóa chất độc hại trong việc phòng trừ bệnh và côn trùng gây hại, nên dẫn đến ô nhiễm môi trường. Kích thích tính kháng lưu dẫn giúp kích hoạt cơ chế tự nhiênkháng bệnh của cây có thể là giải pháp bảo vệ thực vật thay thế an toàn với môi trường. Việc ứng dụng tiến bộ này vào trong sản xuất lúa có thể làm giảm lượng hóa chất sử dụng, đóng góp vào việc giảm thiểu ô nhiễmmôi trường và sự phát triển của một nền nông nghiệp bền vững. Nghiên cứu đã được thực hiện tại nhà lưới trường Đại học Cần Thơ để tuyển chọn hóa chất và phương pháp sử dụng hóa chất để tăng cường sức khỏe giúp cây lúa vượt qua bệnh vàng lùn. Hóa chất kích kháng được sử dụng ở một nồng độ rất thấp (đơn vị là mM). Kết quả cho thấy chiều cao cây lúa khi xử lý chất kích kháng tốt hơn so đối chứng không xử lý. Bên cạnh đó, số cây lúa nhiễm bệnh giảm, tỉ lệ hạt chắc và năng suất tăng khi cây lúa được xử lý với chất kích kháng. Trong số các chất kích kháng đã sử dụng, acid oxalic cho hiệu quả vượt trội. Với chất acid oxalic, phương pháp ngâm hạt cho hiệuquả kích kháng tốt hơn phương pháp áo hạt.

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Mycovirus-Induced Hypervirulence of Leptosphaeria biglobosa Enhances Systemic Acquired Resistance to Leptosphaeria maculans in Brassica napus

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-09-19-0254-r ◽

2020 ◽

Vol 33 (1) ◽

pp. 98-107 ◽

Cited By ~ 1

Author(s):

Unnati A. Shah ◽

Ioly Kotta-Loizou ◽

Bruce D. L. Fitt ◽

Robert H. A. Coutts

Keyword(s):

Brassica Napus ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Leptosphaeria Maculans ◽

Stem Canker ◽

Systemic Resistance ◽

Phoma Stem Canker ◽

Isogenic Lines ◽

Related Proteins ◽

Leptosphaeria Biglobosa

Phoma stem canker (blackleg) is one of the most important diseases of winter oilseed rape (Brassica napus) worldwide and is caused by a complex that comprises at least two species: Leptosphaeria maculans and L. biglobosa. Screening a panel of field Leptosphaeria isolates from B. napus for the presence of mycoviruses revealed the presence of a novel double-stranded RNA quadrivirus in L. biglobosa and no viruses in L. maculans. Following elimination of the mycovirus, virus-infected and virus-free isogenic lines of L. biglobosa were created. A direct comparison of the growth and virulence of these isogenic lines illustrated that virus infection caused hypervirulence and resulted in induced systemic resistance toward L. maculans in B. napus following lower leaf preinoculation with the virus-infected isolate. Analysis of the plant transcriptome suggests that the presence of the virus leads to subtle alterations in metabolism and plant defenses. For instance, transcripts involved in carbohydrate and amino acid metabolism are enriched in plants treated with the virus-infected isolate, while pathogenesis-related proteins, chitinases and WRKY transcription factors are differentially expressed. These results illustrate the potential for deliberate inoculation of plants with hypervirulent L. biglobosa to decrease the severity of Phoma stem canker later in the growing season. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

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Biological and chemical dependent systemic resistance and their significance for the control of root-knot nematodes

Nematology ◽

10.1163/15685411-00002818 ◽

2014 ◽

Vol 16 (8) ◽

pp. 917-927 ◽

Cited By ~ 8

Author(s):

Mohamed E. Selim ◽

Magdy E. Mahdy ◽

Mervat E. Sorial ◽

Abdelfattah A. Dababat ◽

Richard A. Sikora

Keyword(s):

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Systemic Resistance ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Root Knot Nematode ◽

System A ◽

Tomato Roots ◽

Infected Tomato ◽

Abiotic Elicitors

Inducing host plant-based systemic resistance is one of the modes of action involved in tri-trophic interactions between host plants, pests and mutualistic microorganisms. Two different types of systemic resistance – systemic acquired resistance (SAR) and induced systemic resistance (ISR) – were found to be functional against pathogens and plant-parasitic nematodes. In this study, the ability of Trichoderma harzianum isolate T10 and insecticidal active neem powder (NP) to induce systemic resistance in tomato against the root-knot nematode Meloidogyne javanica was compared with salicylic acid (SA) and jasmonic acid (JA) as standard elicitors for SAR and ISR, respectively. Results showed that, when the biotic and abiotic elicitors were applied to the inducer side of a split root plant system, a significant reduction in nematode infection was observed on the responder side. Physiological changes in the tomato plant due to the induction of SAR or ISA by these biotic and abiotic elicitors were further investigated using HPLC. Results demonstrated that T10 significantly increased the accumulation of different metabolites in the shoot of the tomato over the NP, JA and SA elicitors. Furthermore, the results demonstrated that several metabolic, physical and biochemical changes occurred in the shoots of the treated plants with both the biotic and abiotic elicitors. The percentage of membrane leakage (Ml) at nematode-infected tomato roots was significantly high, but the differences in percentage leakage were not significant in other treatments compared to the non-infested control. The best results were recorded with SA, T10 and NP, which gave the lowest MI% compared to the infested plants.

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