scholarly journals Towards the Biological Control of Devastating Forest Pathogens from the Genus Armillaria

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1013 ◽  
Author(s):  
Liqiong Chen ◽  
Bettina Bóka ◽  
Orsolya Kedves ◽  
Viktor Dávid Nagy ◽  
Attila Szűcs ◽  
...  
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Soil Conditions ◽  
Spruce Forests ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Trichoderma Isolates ◽  
Armillaria Species ◽  
Oak Seedlings

Research Highlights: A large scale effort to screen, characterize, and select Trichoderma strains with the potential to antagonize Armillaria species revealed promising candidates for field applications. Background and Objectives: Armillaria species are among the economically most relevant soilborne tree pathogens causing devastating root diseases worldwide. Biocontrol agents are environment-friendly alternatives to chemicals in restraining the spread of Armillaria in forest soils. Trichoderma species may efficiently employ diverse antagonistic mechanisms against fungal plant pathogens. The aim of this paper is to isolate indigenous Trichoderma strains from healthy and Armillaria-damaged forests, characterize them, screen their biocontrol properties, and test selected strains under field conditions. Materials and Methods: Armillaria and Trichoderma isolates were collected from soil samples of a damaged Hungarian oak and healthy Austrian spruce forests and identified to the species level. In vitro antagonism experiments were performed to determine the potential of the Trichoderma isolates to control Armillaria species. Selected biocontrol candidates were screened for extracellular enzyme production and plant growth-promoting traits. A field experiment was carried out by applying two selected Trichoderma strains on two-year-old European Turkey oak seedlings planted in a forest area heavily overtaken by the rhizomorphs of numerous Armillaria colonies. Results: Although A. cepistipes and A. ostoyae were found in the Austrian spruce forests, A. mellea and A. gallica clones dominated the Hungarian oak stand. A total of 64 Trichoderma isolates belonging to 14 species were recovered. Several Trichoderma strains exhibited in vitro antagonistic abilities towards Armillaria species and produced siderophores and indole-3-acetic acid. Oak seedlings treated with T. virens and T. atrobrunneum displayed better survival under harsh soil conditions than the untreated controls. Conclusions: Selected native Trichoderma strains, associated with Armillaria rhizomorphs, which may also have plant growth promoting properties, are potential antagonists of Armillaria spp., and such abilities can be exploited in the biological control of Armillaria root rot.

scholarly journals Selection and Assessment of Plant Growth-Promoting Rhizobacteria for Biological Control of Multiple Plant Diseases

2017 ◽  
Vol 107 (8) ◽  
pp. 928-936 ◽  
Author(s):  
Ke Liu ◽  
Molli Newman ◽  
John A. McInroy ◽  
Chia-Hui Hu ◽  
Joseph W. Kloepper
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Broad Spectrum ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Diseases ◽  
Damping Off ◽  
In Planta ◽  
Plant Growth Promoting ◽  
Growth Promoting

A study was designed to screen individual strains of plant growth-promoting rhizobacteria (PGPR) for broad-spectrum disease suppression in vitro and in planta. In a preliminary screen, 28 of 196 strains inhibited eight different tested pathogens in vitro. In a secondary screen, these 28 strains showed broad spectrum antagonistic activity to six different genera of pathogens, and 24 of the 28 strains produced five traits reported to be related to plant growth promotion, including nitrogen fixation, phosphate solubilization, indole-3-acetic acid production, siderophore production, and biofilm formation. In advanced screens, the 28 PGPR strains selected in vitro were tested in planta for biological control of multiple plant diseases including bacterial spot of tomato caused by Xanthomonas axonopodis pv. vesicatoria, bacterial speck of tomato caused by Pseudomonas syringae pv. tomato, damping-off of pepper caused by Rhizoctonia solani, and damping-off of cucumber caused by Pythium ultimum. In all, 5 of the 28 tested strains significantly reduced three of the four tested diseases, and another 19 strains showed biological control to two tested diseases. To understand the observed broad-spectrum biocontrol capacity, antiSMASH was used to predict secondary metabolite clusters of selected strains. Multiple gene clusters encoding for secondary metabolites, e.g., bacillibactin, bacilysin, and microcin, were detected in each strain. In conclusion, selected individual PGPR strains showed broad-spectrum biocontrol activity to multiple plant diseases.

scholarly journals Biological Control of Meloidogyne incognita by Spore-forming Plant Growth-promoting Rhizobacteria on Cotton

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 774-784 ◽  
Author(s):  
Ni Xiang ◽  
Kathy S. Lawrence ◽  
Joseph W. Kloepper ◽  
Patricia A. Donald ◽  
John A. McInroy ◽  
...  
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Meloidogyne Incognita ◽  
Plant Growth Promoting Rhizobacteria ◽  
Field Trials ◽  
Parasitic Nematodes ◽  
Subtilis Strain ◽  
Plant Growth Promoting ◽  
Growth Promoting

In the past decade, increased attention has been placed on biological control of plant-parasitic nematodes using various fungi and bacteria. The objectives of this study were to evaluate the potential of 662 plant growth-promoting rhizobacteria (PGPR) strains for mortality to Meloidogyne incognita J2 in vitro and for nematode management in greenhouse, microplot, and field trials. Results indicated that the mortality of M. incognita J2 by the PGPR strains ranged from 0 to 100% with an average of 39%. Among the PGPR strains examined, 212 of 662 strains (or 33%) caused significantly greater mortality percent of M. incognita J2 than the untreated control. Bacillus was the major genus initiating a greater mortality percentage when compared with the other genera. In subsequent trials, B. velezensis strain Bve2 reduced M. incognita eggs per gram of cotton root in the greenhouse trials at 45 days after planting (DAP) similarly to the commercial standards Abamectin and Clothianidin plus B. firmus I-1582. Bacillus mojavensis strain Bmo3, B. velezensis strain Bve2, B. subtilis subsp. subtilis strain Bsssu3, and the Mixture 2 (Abamectin + Bve2 + B. altitudinis strain Bal13) suppressed M. incognita eggs per gram of root in the microplot at 45 DAP. Bacillus velezensis strains Bve2 and Bve12 also increased seed-cotton yield in the microplot and field trials. Overall, results indicate that B. velezensis strains Bve2 and Bve12, B. mojavensis strain Bmo3, and Mixture 2 have potential to reduce M. incognita population density and to enhance growth of cotton when applied as in-furrow sprays at planting.

scholarly journals KARAKTERISASI DAN UJI AKTIVITAS BAKTERI RIZOSFER LAHAN ULTISOL SEBAGAI PEMACU PERTUMBUHAN TANAMAN DAN AGENSIA HAYATI CENDAWAN PATOGEN TULAR TANAH SECARA IN VITRO

2010 ◽  
Vol 10 (2) ◽  
pp. 123-130
Author(s):  
Andi Khaeruni ◽  
Gusti Ayu Kade Sutariati ◽  
Sri Wahyuni
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Plant Pathogens ◽  
Nitrogenase Activity ◽  
In Vitro Test ◽  
Biological Control Agents ◽  
Plant Growth Promoting ◽  
Vitro Test ◽  
Growth Promoting

Characterization and activities assay of rhizosphere bacteria from ultisol land for plant-growth promoting and biocontrol agents of soil-borne fungus pathogens under in vitro test.  Although many studies have been conducted to identify the specific traits of the plant growth-promoting and bioprotecting rhizobacteria (PGPBR), they were limited to studying specific PGPBR isolates from ultisol lands.  We selected 273 isolates from bulk soil and plant rhizosphere and examined them for a wide array traits that might inhibit the growth of plant pathogens and increase early cucumber growth in ultisol soil.  A subsample of 25 isolates, all positively produce chitinase and sellulose enzymes, 18 positively produce protease and 7 were fluorescens on KB medium under UV lighting.  All isolates could produce IAA and be able to solubilize phosphor in vitro test, 10 exhibited low level of nitrogenase activity. Futher test showed that out of 25 isolates, 12  inhibited F. oxysporum, P. capsici, R. solani and S. rolfsii in vitro.  All isolates increased seed germination, but only 5 isolates significanty increased early cucumber growth in ultisol soil. The results suggest that rhizobacteria be able to produce extracelluler enzymes, siderophore, ACC deasiminase, and IAA or those which are able to solubilize phosphor in vitro may be potential to be uses as biofertilizer and biological control agents in ultisol land.

Molecular imaging of plant-microbe interactions on the Brachypodium seed surface

The Analyst ◽  
2021 ◽  
Author(s):  
Yuchen Zhang ◽  
Rachel Komorek ◽  
Jiyoung Son ◽  
Shawn Riechers ◽  
Zihua Zhu ◽  
...  
Keyword(s):  
Biological Control ◽  
Molecular Imaging ◽  
Plant Growth ◽  
Crucial Role ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Tissues ◽  
Seed Surface ◽  
Plant Growth Promoting ◽  
Microbe Interactions ◽  
Growth Promoting

Plant growth-promoting rhizobacteria (PGPR) play a crucial role in biological control and pathogenic defense on and within plant tissues, however the mechanism(s) by which plants associate with PGPR to elicit...

scholarly journals A prospectus of plant growth promoting endophytic bacterium from orchid (Vanda cristata)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sujit Shah ◽  
Krishna Chand ◽  
Bhagwan Rekadwad ◽  
Yogesh S. Shouche ◽  
Jyotsna Sharma ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Colonization ◽  
Endophytic Bacterium ◽  
Epifluorescence Microscopy ◽  
In Vitro Cultivation ◽  
Rrna Gene ◽  
Bacillus Spp ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract Background A plant growth-promoting endophytic bacterium PVL1 isolated from the leaf of Vanda cristata has the ability to colonize with roots of plants and protect the plant. PVL1 was isolated using laboratory synthetic media. 16S rRNA gene sequencing method has been employed for identification before and after root colonization ability. Results Original isolated and remunerated strain from colonized roots were identified as Bacillus spp. as per EzBiocloud database. The presence of bacteria in the root section of the plantlet was confirmed through Epifluorescence microscopy of colonized roots. The in-vitro plantlet colonized by PVL1 as well as DLMB attained higher growth than the control. PVL1 capable of producing plant beneficial phytohormone under in vitro cultivation. HPLC and GC-MS analysis suggest that colonized plants contain Indole Acetic Acid (IAA). The methanol extract of Bacillus spp., contains 0.015 μg in 1 μl concentration of IAA. PVL1 has the ability to produce antimicrobial compounds such as ethyl iso-allocholate, which exhibits immune restoring property. One-way ANOVA shows that results were statistically significant at P ≤ 0.05 level. Conclusions Hence, it has been concluded that Bacillus spp. PVL1 can promote plant growth through secretion of IAA during root colonization and ethyl iso-allocholate to protect plants from foreign infections. Thus, this study supports to support Koch’s postulates of bacteria establishment.

scholarly journals Multi-Trait Wheat Rhizobacteria from Calcareous Soil with Biocontrol Activity Promote Plant Growth and Mitigate Salinity Stress

2021 ◽  
Vol 9 (8) ◽  
pp. 1588
Author(s):  
Anastasia Venieraki ◽  
Styliani N. Chorianopoulou ◽  
Panagiotis Katinakis ◽  
Dimitris L. Bouranis
Keyword(s):  
Plant Growth ◽  
Salinity Stress ◽  
Calcareous Soil ◽  
In Vitro Studies ◽  
Pgp Traits ◽  
Biocontrol Activity ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Microbial Fertilizers

Plant growth promoting rhizobacteria (PGPR) can be functional microbial fertilizers and/or biological control agents, contributing to an eco-spirit and safe solution for chemical replacement. Therefore, we have isolated rhizospheric arylsulfatase (ARS)-producing bacteria, belonging to Pseudomonas and Bacillus genus, from durum wheat crop grown on calcareous soil. These isolates harbouring plant growth promoting (PGP) traits were further evaluated in vitro for additional PGP traits, including indole compounds production and biocontrol activity against phytopathogens, limiting the group of multi-trait strains to eight. The selected bacterial strains were further evaluated for PGP attributes associated with biofilm formation, compatibility, salt tolerance ability and effect on plant growth. In vitro studies demonstrated that the multi-trait isolates, Bacillus (1.SG.7, 5.SG.3) and Pseudomonas (2.SG.20, 2.C.19) strains, enhanced the lateral roots abundance and shoots biomass, mitigated salinity stress, suggesting the utility of beneficial ARS-producing bacteria as potential microbial fertilizers. Furthermore, in vitro studies demonstrated that compatible combinations of multi-trait isolates, Bacillus sp. 1.SG.7 in a mixture coupled with 5.SG.3, and 2.C.19 with 5.SG.3 belonging to Bacillus and Pseudomonas, respectively, may enhance plant growth as compared to single inoculants.

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