Agrobacterium-mediated transformation of chitinase gene from the actinorhizal tree Casuarina equisetifolia in Nicotiana tabacum

Biologia ◽  
2015 ◽  
Vol 70 (7) ◽  
Author(s):  
Radha Veluthakkal ◽  
Modhumita Ghosh Dasgupta

AbstractGenetic transformation of plants offers the possibility of testing hypotheses on the function of individual genes and enables exploration of transgenes for targeted trait improvement. Cloning of the full-length class I chitinase from the Casuarina equisetifolia (CeChi1) was earlier reported by our team. In the present study, tobacco was used as a model system to functionally evaluate the potential of CeChi1 driven by ubiquitin promoter. The pUH-CeChi1 construct was introduced into tobacco by Agrobacterium-mediated transformation and the putative transformants were confirmed for stable gene integration, transgene expression and recombinant protein production using PCR, RT-qPCR, antifungal assays and in planta analysis. The in vitro antifungal bioassay using the total proteins from leaves of transformed plantlets revealed the characteristic lysis of hyphal tips of pathogenic fungi including Trichosporium vesiculosum, Fusarium oxysporum and Rhizoctonia solani. The in planta bioassay of transformed tobacco showed reduced disease symptoms when compared to untransformed wild plants. The study revealed that the class I chitinase isolated from C. equisetifolia can act as a potential gene resource in future transformation programs for incorporating disease tolerance.

Plant Disease ◽  
2009 ◽  
Vol 93 (10) ◽  
pp. 1037-1043 ◽  
Author(s):  
Young-Ki Jo ◽  
Byung H. Kim ◽  
Geunhwa Jung

Silver in ionic or nanoparticle forms has a high antimicrobial activity and is therefore widely used for various sterilization purposes including materials of medical devices and water sanitization. There have been relatively few studies on the applicability of silver to control plant diseases. Various forms of silver ions and nanoparticles were tested in the current study to examine the antifungal activity on two plant-pathogenic fungi, Bipolaris sorokiniana and Magnaporthe grisea. In vitro petri dish assays indicated that silver ions and nanoparticles had a significant effect on the colony formation of these two pathogens. Effective concentrations of the silver compounds inhibiting colony formation by 50% (EC50) were higher for B. sorokiniana than for M. grisea. The inhibitory effect on colony formation significantly diminished after silver cations were neutralized with chloride ions. Growth chamber inoculation assays further confirmed that both ionic and nanoparticle silver significantly reduced these two fungal diseases on perennial ryegrass (Lolium perenne). Particularly, silver ions and nanoparticles effectively reduced disease severity with an application at 3 h before spore inoculation, but their efficacy significantly diminished when applied at 24 h after inoculation. The in vitro and in planta evaluations of silver indicated that both silver ions and nanoparticles influence colony formation of spores and disease progress of plant-pathogenic fungi. In planta efficacy of silver ions and nanoparticles is much greater with preventative application, which may promote the direct contact of silver with spores and germ tubes, and inhibit their viability.


2018 ◽  
Author(s):  
Graeme J. Kettles ◽  
Bernhard J. Hofinger ◽  
Pingsha Hu ◽  
Carlos Bayon ◽  
Jason J. Rudd ◽  
...  

AbstractCross-kingdom small RNA (sRNA) silencing has recently emerged as a mechanism facilitating fungal colonization and disease development. Here we characterized RNAi pathways in Zymoseptoria tritici, a major fungal pathogen of wheat, and assessed their contribution to pathogenesis. Computational analysis of fungal sRNA and host mRNA sequencing datasets was used to define the global sRNA populations in Z. tritici and predict their mRNA targets in wheat. 389 in planta-induced sRNA loci were identified. sRNAs generated from some of these loci were predicted to target wheat mRNAs including those potentially involved in pathogen defense. However, molecular approaches failed to validate targeting of selected wheat mRNAs by fungal sRNAs. Mutant strains of Z. tritici carrying deletions of genes encoding key components of RNAi such as Dicer-like (DCL) and Argounate (AGO) proteins were generated, and virulence bioassays suggested that these are dispensable for full infection of wheat. Nonetheless, our results did suggest the existence of non-canonical DCL-independent pathway(s) for sRNA biogenesis in Z. tritici. dsRNA targeting essential fungal genes applied in vitro or generated from an RNA virus vector in planta in a procedure known as HIGS (Host-Induced Gene Silencing) was ineffective in preventing Z. tritici growth or disease. We also demonstrated that Z. tritici is incapable of dsRNA uptake. Collectively, our data suggest that RNAi approaches for gene function analyses in this fungal species and potentially also as a control measure may not be as effective as has been demonstrated for some other plant pathogenic fungi.


2020 ◽  
Vol 22 (2) ◽  
pp. 70-78
Author(s):  
Arum Saputri ◽  
Loekas Soesanto ◽  
Abu Umayah ◽  
Agus Sarjito

[EXPLORATION AND VIRULENT TEST OF MAIZE ENDOPHYTE Bacillus sp. AGAINST MAIZE SHEATH BLIGHT]. Capability of endophytic bacterial, effectivity, and its effect on R. solani. and on maize seedlings growth were investigated from April 2018 to January 2019. Exploration of endophytes bacteria in maize was taken from Banyumas Regency (Sumbang, Kembaran, Baturraden) and Purbalingga Regency (Padamara, Bojongsari, Pratin). Taking plant samples using Purposive Random Sampling and Diagonal Sampling methods. Completely randomized design was used in in vitro test with 16 treatments repeated twice. Completely randomized block design was used in in planta experiment with 5 treatments repeated 5 times. The treatment consisted of control, fungiside (mankozeb), and 2 isolates of endophytes bacteria performing the best in vitro result. Variables observed included characteristics of endophytic bacteria and pathogenic fungi, inhibition diameter, incubation period, disease intensity, incidence of disease, AUDPC, plant height, leaf number, root length, plant fresh weight, canopy fresh weight, and root fresh weight. Resultshowed that the exploration obtained 15 endophytic Bacillus sp. isolates. The PD A.4 and BK A.1 isolates werw able to inhibit the growth of pathogenic fungi in-vitro by 56.93 and 51.5%, respectively. The soaking treatment using BK A1 was able to reduce disease intensity by 59.377%, and AUDPC value 34.19%. Endophytic bacteria influence plant height, plant fresh weight, canopy fresh weight, and fresh weight of roots respectively as 89.17 cm, 126.06 g, 106.67 g and 19.4 g.


2000 ◽  
Vol 182 (12) ◽  
pp. 3508-3516 ◽  
Author(s):  
Erik L. Hendrickson ◽  
Pablo Guevera ◽  
Frederick M. Ausubel

ABSTRACT β-Glucuronidase (uidA) reporter gene fusions were constructed for the hrpZ, hrpL, andhrpS genes from the phytopathogen Pseudomonas syringae pv. maculicola strain ES4326. These reporters, as well as an avrRpt2-uidA fusion, were used to measure transcriptional activity in ES4326 and a ES4326 rpoNmutant. rpoN was required for the expression ofavrRpt2, hrpZ, and hrpL in vitro in minimal media and in vivo when infiltrated into Arabidopsis thaliana leaves. In contrast, the expression of hrpSwas essentially the same in wild-type and rpoN mutant strains. Constitutive expression of hrpL in anrpoN mutant restored hrpZ transcription to wild-type levels, restored the hypersensitive response when infiltrated into tobacco (Nicotiana tobacum), and partially restored the elicitation of virulence-related symptoms but not growth when infiltrated into Arabidopsis leaves. These data indicate that rpoN-mediated control of hrp gene expression acts at the level of hrpL and that in planta growth of P. syringae is not required for the elicitation of disease symptoms.


2021 ◽  
Vol 21 (2) ◽  
pp. 82-90
Author(s):  
Loekas Soesanto ◽  
Lintang Yunita Sari ◽  
Endang Mugiastuti ◽  
Abdul Manan

Cross application of entomopathogenic fungi raw secondary metabolites for controlling fusarium wilt of chili seedlings. Theresearch aimed to determine the effect of entomopathogenic fungi raw secondary metabolites on fusarium wilt on chili plants and on growth of chili. In vitro test used a Completely Randomized Design with 5 treatments and 5 replicate and in planta using a Randomized Block Design with 5 treatments and 5 replicatie including control, secondary metabolites of Beauveria bassiana B10, B. bassiana B16, Metarhizium anisopliae M16, dan Lecanicillium lecanii L16. Variables observed included inhibition ability, incubation period, desease intensity, plant height, root length, and phenolic compounds (tannins, saponin, and hydroquinone) content qualitatively. The results showed that secondary metabolites of B. bassiana B10, B. bassiana B16, M. anisopliae M16, and L. lecanii L16 were able to inhibit growth of Fusarium oxysporum f.sp. capsici by 50.62; 50,64; 48,62; 56.62%, respectively, extend incubation periods of 71.05; 73,38; 64.89; and 68.57%, respectively, suppress disease intensity by 99.99; 99.99; 99.99; and 99.99%, respectively, can increase plant height by 15.22; 18.8; 21.14; 21.69%, respectively, increasing the root length by 22.61; 25,71; 26,34; 33.50%, respectively, and can increase the content of tannins, saponins and hydroquinone compounds qualitatively compared to controls. The secondary metabolites of enthomopathogenic fungi could be used as organic control for soilborne pathogenic fungi.


2020 ◽  
pp. 1-13
Author(s):  
Azadeh Yasari ◽  
Nuanyi Liang ◽  
Aidin Foroutan ◽  
Michael G. Gänzle ◽  
Stephen E. Strelkov ◽  
...  

Pathogenic fungi cause significant yield losses and quality reductions to many crops including canola, wheat, and barley. Toxic metabolites produced by fungal pathogens, along with excessive application of synthetic fungicides, can also pose risks to human and livestock health. Hydroxy unsaturated fatty acids (HUFAs) are novel alternatives to commonly used fungicides. Here, the antifungal activities of two HUFAs, coriolic acid (CA) and ricinoleic acid (RA), were assessed in vitro and in planta for their activity against the important phytopathogens Fusarium graminearum Schwabe, Pyrenophora tritici-repentis (Died.) Drechsler, Pyrenophora teres f. teres Drechsler, Sclerotinia sclerotiorum (Lib.) de Bary, Leptosphaeria maculans Ces. & De Not., and Aspergillus niger Tiegh. on selected media, monocots or dicots. The results in vitro indicated that both CA and RA showed the strongest inhibitory activity against L. maculans and A. niger, but their activities varied with different fungi. On wheat and barley, CA but not RA reduced disease severity caused by Pyrenophora spp.; on canola, treatment with high levels of CA and RA led to oxidative damage of the plant tissues, and treatment with low concentrations of CA and RA did not reduce disease severity caused by L. maculans or S. sclerotiorum on canola. Our findings suggest that the utility of HUFAs in reducing disease severity caused by pathogenic fungi depends on the dosage and the plant and fungus targeted. High concentrations of HUFA can be phytotoxic on certain plants. In addition to their direct antifungal properties, additional mechanisms may be involved in the disease reduction of CA, suggesting the need for further evaluation of its potential use in crop protection.


2020 ◽  
Vol 110 (10) ◽  
pp. 1657-1667
Author(s):  
Laura Ortega ◽  
Katherine A. Walker ◽  
Casey Patrick ◽  
Yeshi Wamishe ◽  
Alejandro Rojas ◽  
...  

Bacterial panicle blight of rice is a seedborne disease caused by the bacterium Burkholderia glumae. This disease has affected rice production worldwide and its effects are likely to become more devastating with the continuous increase in global temperatures, especially during the growing season. The bacterium can cause disease symptoms in different tissues and at different developmental stages. In reproductive stages, the bacterium interferes with grain development in the panicles and, as a result, directly affects rice yield. Currently, there are no methods to control the disease because chemical control is not effective and completely resistant cultivars are not available. Thus, a promising approach is the use of antagonistic microorganisms. In this work, we identified one strain of Pseudomonas protegens and one strain of B. cepacia with antimicrobial activity against B. glumae in vitro and in planta. We further characterized the antimicrobial activity of P. protegens and found that this activity is associated with bacterial secretions. Cell-free secretions from P. protegens inhibited the growth of B. glumae in vitro and also prevented B. glumae from causing disease in rice. Although the specific molecules associated with these activities have not been identified, these findings suggest that the secreted fractions from P. protegens could be harnessed as biopesticides to control bacterial panicle blight of rice.


2021 ◽  
Vol 9 (9) ◽  
pp. 1924
Author(s):  
Pierre Joly ◽  
Alexandra Calteau ◽  
Aurélie Wauquier ◽  
Rémi Dumas ◽  
Mylène Beuvin ◽  
...  

Agriculture is in need of alternative products to conventional phytopharmaceutical treatments from chemical industry. One solution is the use of natural microorganisms with beneficial properties to ensure crop yields and plant health. In the present study, we focused our analyses on a bacterium referred as strain B25 and belonging to the species Bacillus velezensis (synonym B. amyloliquefaciens subsp. plantarum or B. methylotrophicus), a promising plant growth promoting rhizobacterium (PGPR) and an inhibitor of pathogenic fungi inducing crops diseases. B25 strain activities were investigated. Its genes are well preserved, with their majority being common with other Bacillus spp. strains and responsible for the biosynthesis of secondary metabolites known to be involved in biocontrol and plant growth-promoting activities. No antibiotic resistance genes were found in the B25 strain plasmid. In vitro and in planta tests were conducted to confirm these PGPR and biocontrol properties, showing its efficiency against 13 different pathogenic fungi through antibiosis mechanism. B25 strain also showed good capacities to quickly colonize its environment, to solubilize phosphorus and to produce siderophores and little amounts of auxin-type phytohormones (around 13,051 µg/mL after 32 h). All these findings combined to the fact that B25 demonstrated good properties for industrialization of the production and an environmental-friendly profile, led to its commercialization under market authorization since 2018 in several biostimulant preparations and opened its potential use as a biocontrol agent.


Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 59
Author(s):  
Mallika Kumarihamy ◽  
Luiz H. Rosa ◽  
Natascha Techen ◽  
Daneel Ferreira ◽  
Edward M. Croom ◽  
...  

The metabolic pathways in the apicoplast organelle of Plasmodium parasites are similar to those in plastids in plant cells and are suitable targets for malaria drug discovery. Some phytotoxins released by plant pathogenic fungi have been known to target metabolic pathways of the plastid; thus, they may also serve as potential antimalarial drug leads. An EtOAc extract of the broth of the endophyte Botryosphaeria dothidea isolated from a seed collected from a Torreya taxifolia plant with disease symptoms, showed in vitro antimalarial and phytotoxic activities. Bioactivity-guided fractionation of the extract afforded a mixture of two known isomeric phytotoxins, FRT-A and flavipucine (or their enantiomers, sapinopyridione and (-)-flavipucine), and two new unstable γ-lactam alkaloids dothilactaenes A and B. The isomeric mixture of phytotoxins displayed strong phytotoxicity against both a dicot and a monocot and moderate cytotoxicity against a panel of cell lines. Dothilactaene A showed no activity. Dothilactaene B was isolated from the active fraction, which showed moderate in vitro antiplasmodial activity with high selectivity index. In spite of this activity, its instability and various other biological activities shown by related compounds would preclude it from being a viable antimalarial lead.


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