The FTIR spectroscopy investigation of the cellular components of cassava after sensitization with plant growth promoting rhizobacteria, [i]Bacillus subtili[/i]s CaSUT007

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699To evaluate the response of cassava stakes to plant growth promoting rhizobacteria, Bacillus subtilis CaSUT007, the changes in cellular compositions and phytohormone were investigated using the fourier transform infrared (FTIR) and high-performance liquid chromatography (HPLC) approach. The objective of this study was to test the hypothesis that CaSUT007 stimulates production of plant cellular components and phytohormone involved in metabolism and growth development mechanisms. Cassava stake treated with CaSUT007 or with sterile distilled water were germinated in sterile soil, after incubation for 28 days, CaSUT007 treated cassava stakes had more lateral root, longer roots, shoot length and greater biomass than the control which enhanced more than 1.3 fold of the cassava's phytohormone as indole-3-acetic acid content of non-treated control. We also focused on plant cellular composition and cassava stake tissues from the two treatments were harvested for FTIR analysis. FTIR analyses revealed that higher accumulated of lipid in response to the strain CaSUT007. The cassava stake treated with the beneficial bacteria B. subtilis strain CaSUT007 showed the higher content of the lipid content as (shown in the spectral regions of CH stretching and CH bending mode associated with cell membrane structure lipids) when compared with those of the cassava stake treated with distilled water. Our results initially demonstrated that CaSUT007 can enhance plant growth under greenhouse conditions by direct stimulation of plant lipid and phytohormone as indole-3-acetic acid production

The antagonistic activity of Trichoderma virens strain TvSUT10 against cassava stem rot in Thailand

In this current study, the beneficial filamentous fungi, Trichoderma virens, isolated from cassava field were investigated for antagonistic mode of action against Lasiodiplodia theobromae, the causal agent of cassava stem rot in Thailand. In vitro screening using the dual culture technique was undertaken to assess the potential of these Trichoderma isolates. Our results indicated that fifteen isolates of T. virens were collected from various areas of cassava field in Nakhon Ratchasima, Thailand. The T. virens isolate, TvSUT10, was the most effective isolate and inhibited L. theobromae mycelial growth by 84.12%, due to the antagonistic mechanism. Moreover, Trichoderma β-1,3-glucanase activity was determined, the result revealed that the highest activity was recorded in strain of T. virens TvSUT10 (25.7 U/ml). In addition, in the greenhouse experiment, the application of the TvSUT10 as a conidial suspension reduced the stem rot disease severity of cassava caused by 53%. The results indicated that the T. virens strain TvSUT10 has initial modes of action of biological control to protect cassava crop against L. theobromae infections in cassava.Key words: Trichoderma, cassava stem rot disease, growth inhibition, cassava, biocontrol

Application of Wood Vinegar for Fungal Disease Controls in Paddy Rice

A survey of an outbreak of fungal diseases of rice variety Phitsanulok2 (PLS91014-16-1-5-1) was conducted in Thailand during June 2014 to January 2015 using a W-random sampling pattern. The study revealed the incidence of several diseases including brown spot (Bipolaris oryzae), narrow brown leaf streak (Cercospora oryzae), and dirty panicle (Alternaria padwickii, C. oryzae, Curvularia lunata, Fusarium semitectum, and B. oryzae). This study evaluated the efficacy of wood vinegar for control of these fungal diseases. A compleel randomized design was used, using the above variety in 3 replications. In the laboratory we found wood vinegar to be effective in inhibiting growth of representative pathogens such as C. lunata, B. oryzae, F. semitectum, and A. padwickii, the causal agent of dirty panicle disease. The field results confirmed the efficacy of wood vinegar under greenhouse conditions, with significantly reduced disease incidence of brown spot and dirty panicle, and significantly enhanced germination, seedling vigor, shoot height, root length, and fresh weight, when compared with the untreated control. However, seed treatment and 6 foliar sprays of wood vinegar under field conditions at Ang Thong showed no significant differences from the conventional treatment in suppression of brown spot, narrow brown leaf streak, and dirty panicle. The result demonstrates a promising alternative approach to control of key rice diseases

Foliar application of systemic acquired resistance (SAR) inducers for controlling grape anthracnose caused by Sphaceloma ampelinum de Bary in Thailand

Chitosan and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) are active-elicitors that induce protection in grapevine against several diseases. In this study, treatment of grapevine with chitosan and BTH provided protection to anthracnose, caused by Sphaceloma ampelinum. Chitosan and BTH treatment also increased chitinase, ß-1,3-glucanase and peroxidase activities levels in leaves over non-treated plants. Differential accumulation of these traits was more rapid and pronounced when chitosan and BTH treated plants were infected with S. ampelinum; this pattern indicating priming. The induced resistance by chitosan and BTH was also associated with increased production of salicylic acid (SA) in grapevine leaves, suggesting that SA-dependent signaling pathways are systemically triggered by these compounds. Apart from proteins with defense-related function, most of the proteins induced by chitosan and BTH were involved in defense mechanism, reflecting the strong direct positive effect that chitosan and BTH has on grapevine tolerance to anthracnose disease infection.Keywords: Anthracnose, grapevine, induce resistance, systemic acquired resistance (SAR) biochemical markers, Sphaceloma ampelinumAfrican Journal of Biotechnology Vol. 12(33), pp. 5148-515

Biochemical adaptation of phytopathogenic fungi, Sclerotium rolfsii, in response to temperature stress

Temperature stress plays a critical influence on microbial survival and ecology. It has been reported to be associated with direct effects on microbial metabolisms, but there are very few studies in literature which have reported it in phytopathogenic fungi. In this study, we investigated the impact of two different temperature conditions, 28 and 32°C on the changes of Sclerotium rolfsii cellular components using Fourier transform infrared (FT-IR) spectroscopy and enzyme activities measurement. Our results demonstrate that growth, sclerotia germination and biomass of S. rolfsii were obviously increased at 32°C. The changes in defense enzymes activity as peroxidase (POX) generally decrease and changed at 32°C. Moreover, the culture of S. rolfsii grown at 32°C shows the higher content of the lipid content as shown in the spectral regions of CH stretching and bending bands, when compared with those of this fungi culture under temperature at 28°C, indicating that these indicators played a role in biochemical adaptation in S. rolfsii, probably due to enhanced activity of the fungal metabolism pathway and cell wall/membrane protection to temperature stress. Our findings illustrate that temperature stress caused increase biomass and lipid composition; whereas decrease in POX activities, which is a key enzyme helps S. rolfsii cope with survival at higher temperature. Key words: Sclerotium rolfsii, enzyme activities, stress response, cellular composition, FT-IR spectroscopy

Rhizosphere Microorganisms Supply Availability of Soil Nutrients and Induce Plant Defense

Plant health is necessary for food security, which is a key determinant of secure and sustainable food production systems. Deficiency of soil nutrients and invasion of plant pathogens or insects are the main destroyers of the world’s food production. Synthetic fertilizers and chemical-based pesticides are frequently employed to combat the problems. However, these have negative impacts on microbial ecosystems and ecosystem functioning. Rhizosphere microorganisms have demonstrated their potency to improve or manage plant nutrients to encourage plant growth, resulting in increased yield and quality by converting organic and inorganic substances around the rhizosphere zone into available plant nutrients. Besides regulating nutrient availability and plant growth enhancement, rhizobacteria or fungi can restrict plant pathogens that cause disease by secreting inhibitory chemicals and boosting plant immunity to combat pests or pathogens. Thus, rhizosphere microorganisms are viewed as viable, alluring economic approaches for sustainable agriculture as biofertilizers and biopesticides. This review provides an overview of the role of rhizosphere microorganisms in soil nutrients and inducing of plant defenses. Moreover, a discussion is presented surrounding the recent consequences of employing these microorganisms and a sustainable strategy towards improving fertilization effectiveness, and encouraging stronger, more pest-resistant plants

Application of Wood Vinegar for Fungal Disease Controls in Paddy Rice

A survey of an outbreak of fungal diseases of rice variety Phitsanulok2 (PLS91014-16-1-5-1) was conducted in Thailand during June 2014 to January 2015 using aW-random sampling pat-tern. The study revealed the incidence of several diseases including brown spot (Bipolaris oryzae), narrow brown leaf streak (Cercospora oryzae), and dirty panicle (Alternaria padwickii, C. oryzae, Curvularia lunata, Fusarium semitectum, and B. oryzae). This study evaluated the ef-ficacy of wood vinegar for control of these fungal diseases. A compleel randomized design was used, using the above variety in 3 replications. In the laboratory we found wood vinegar to be effective in inhibiting growth of representative pathogens such as C. lunata,B. oryzae,F. semi-tectum, and A. padwickii, the causal agent of dirty panicle disease. The field results confirmed the efficacy of wood vinegar under greenhouse conditions, with significantly reduced disease incidence of brown spot and dirty panicle, and significantly enhanced germination, seedling vigor,shoot height, root length, and fresh weight, when compared with the untreated control. However, seed treatment and 6 foliar sprays of wood vinegar under field conditions at Ang Thong showed no significant differences from the conventional treatment in suppression of brown spot, narrow brown leaf streak, and dirty panicle. The result demonstrates a promising alternative approach to control of key rice diseases.</jats:p