Volume 8 - Issue 3 (SI Biotechnology)


Article Number 1
Title

Editorial - Biotechnology special issue

Authors

Gupta V

Received 20 February 2017
Accepted 20 February 2017
Published Online 21 February 2017
Corresponding Author Vijai Gupta 00– vijaifzd@gmail.com
Abstract
Keywords
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Article Number 2
Title

Mycosphere Essay 17 Arbuscular mycorrhizal symbiosis and drought tolerance in crop plants.

Authors

Mathimaran N, Mahaveer P Sharma, Mohan Raju B, Bagyaraj DJ

Received 17 December 2015
Accepted 25 January 2017
Published Online 21 February 2017
Corresponding Author D. J. Bagyaraj – djbagyaraj@gmail.com
Abstract

Drought dramatically reduces crop yield, therefore remains as a major threat to food security. Overcoming drought by crop plants is a complex phenomenon – where plants find ways mainly through physiological adaptation. However, in nature, the plants rely also on microbes for mitigating the drought effects. Below ground association of plant roots with rhizosphere microorganisms for tolerating drought has been though established earlier, the exact mechanism is being understood only recently. The role of below ground microbes, particularly by the arbuscular mycorrhizal fungi (AMF), in drought tolerance by crop plants is currently a key research topic. The significance and highlights of the recent research as well as the past understanding of mechanisms by which crop plants tolerate drought through association of soil beneficial microbes, particularly with that of the AMF, is discussed in this review.

Keywords Antioxidants – Mycorrhizal fungi – Osmotic adjustment – Plant water relations – Water stress
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Article Number 3
Title

Pathogenicity and cytological examination of adapted and non-adapted Bipolaris species on resistant and susceptible cultivars of rice and corn

Authors

Amorio DJH, Cumagun CJR

Received 17 December 2015
Accepted 25 January 2017
Published Online 21 February 2017
Corresponding Author Cumagun CJR – christian_cumagun@yahoo.com
Abstract

The genus Bipolaris causes two important cereal diseases: brown spot of rice (Bipolaris oryzae) and leaf spot of corn (Bipolaris maydis). This study examined the morphology of the two Bipolaris species and its pathogenicity and cytology on resistant and susceptible rice and corn cultivars. Resistant (CH-45) and susceptible (IR-72) rice cultivars were inoculated with B. oryzae (adapted) and B. maydis (non-adapted) isolates. B. oryzae was pathogenic on both rice cultivars producing higher lesion density and size on the susceptible cultivar at 3 to 5 days after inoculation which is significantly different from the resistant cultivar (P=0.05). B. maydis was non-pathogenic on both rice cultivars. Resistant (Sweet Grande) and susceptible (SuperSweet) corn cultivars were also inoculated with two Bipolaris spp. B. maydis was pathogenic on both corn cultivars producing higher lesion density and size on the susceptible cultivar at 7 days after inoculation which is significantly different from the resistant cultivar (P=0.05). B. oryzae was non-pathogenic on both corn cultivars. At the cytological level, conidia of both Bipolaris species germinated on two hosts but only B. maydis produced appressoria on resistant and susceptible corn cultivars. H2Oaccumualtion around the hyphal tips is due to the turgor pressure exerted by the hyphae which forces the DAB stain to acumulate in the immediate surrounding of the swollen hyphae at 24 h after inocualtion. In contrast, death cells, also a form of defense response were formed around the attempted penetration site on resistant rice cultivar inoculated with B. maydis at 24 h after inoculation. This study suggests that in rice-corn cropping system, B. oryzae is not a potential source of inoculum for leaf spot of corn. Likewise, B. maydis is not a potential source of inoculum for brown spot of rice. 

Keywords brown spot of rice – host range – leaf spot of corn
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Article Number 4
Title

Cellulose-degrading enzyme production by Clonostachys byssicola: Partial purification and characterization of an endoglucanase

Authors

Sciuto DL, Almeida RM, Miller RNG, Moreira LRS, Filho EXF

Received 17 December 2015
Accepted 25 January 2017
Published Online 09 March 2017
Corresponding Author Edivaldo Ximenes Ferreira Filho – eximenes@unb.br
Abstract

Agro-industrial wastes offer potential as renewable carbon sources for microbial growth and industrial enzyme production, with potential applications in textile and biofuel industries, among others. The filamentous fungus Clonostachys byssicola was cultivated for seven days in liquid medium containing 1% (w/v) soybean hulls as unique carbon source. Hemicellulase, cellulase and pectinase activities were observed in the crude extract after seven days growth. A CMCase, denominated Cb-Cel, was partially purified using ultrafiltration and chromatographic methods. With a molecular weight of 48 kDa, the enzyme was most active at 70°C and pH 5.0, and thermostable at 40 and 50°C. Cb-Cel showed Km and Vmax values of 15.81 ± 1.65 mg/mL and 0.59 ± 0.03 IU/mL, respectively. Phenolic compounds (tannic, 4‑hydroxybenzoic, ferulic, ρ-coumaric, cinnamic acids and vanillin) had no inhibitory or deactivator effects on enzymatic activity when tested on the concentrated fraction or Cb-Cel. Enzymatic hydrolysis of CMC and filter paper hydrolysis resulted in the release of glucose, cellopentaose and cellohexaose. Enzymatic hydrolysis of soybean hulls released mostly cellohexaose, cellopentase, mannose and xylobiose. In comparison to hydrolysis of sugarcane bagasse, the hydrolysis of soybean hulls yielded higher amounts of reducing sugars, suggesting that the enzymes secreted during growth of C. byssicola are more active on this substrate as carbon source. 

Keywords Cellulase - Enzymatic Hydrolysis – Phenolic Compounds - Soybean Hulls
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Article Number 5
Title

Impact of xylanase expression-inducing compounds on DNA accessibility in Trichoderma reesei.

Authors

Rassinger A, Mello-de-Sousa TM, Regnat K, Derntl C, Mach RL, Mach-Aigner

Received 17 December 2015
Accepted 25 January 2017
Published Online 09 March 2017
Corresponding Author Astrid R. Mach-Aigner – astrid.mach-aigner@tuwien.ac.at
Abstract

The ascomycete Trichoderma reesei produces industrially applied plant cell wall-degrading enzymes. The two major xylanases XYNI (encoded by xyn1) and XYNII (encoded by xyn2) are amongst those enzymes. The transactivator Xyr1, the repressor Cre1, and gene-specific transcription factors regulate the expression of both xylanases. The inducing compounds D-xylose and sophorose trigger the expression of the xylanases, however, to different extents. D-glucose causes carbon catabolite repression (CCR) mediated by Cre1, which leads to a down-regulation of expression of both. Apart from transcription factors, DNA packaging adds an important layer to the regulation of the production of xylanolytic enzymes. In this study the chromatin status in two upstream regulatory regions (URRs) of the xyn1 and xyn2 genes and the transcript levels were investigated in the wild-type strain QM6a and the hypercellulolytic mutant Rut-C30. This analysis demonstrated more open chromatin and higher transcript levels in both strains and genes under at least one of the two inducing conditions. Additionally, a generally more open chromatin could be observed in Rut-C30 independent of the carbon source that was accompanied by elevated transcript levels. In vivo footprinting analyses demonstrated that protein-DNA interactions differ between D-xylose compared to D-glucose in both strains. In addition, different DNA occupancies were observed in the URR of xyn2 in dependency of the applied inducer. Obviously, the usage of a certain inducer influences the final promoter architecture.

Keywords Chromatin – D-xylose – Inducers – sophorose – Trichoderma reesei – xylanases
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Article Number 6
Title

Mycosphere Essay 18: Biotechnological Advances of Beneficial Fungi For Plants.

Authors

Kumar P, Pagano M, O’Donovan A.

Received 17 December 2015
Accepted 25 January 2017
Published Online 09 March 2017
Corresponding Author Marcela Pagano – marpagano@gmail.com
Abstract
Keywords
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Article Number 7
Title

Industrial an environmental applications of white-rot fungi.

Authors

Rodríguez-Couto S

Received 25 December 2015
Accepted 25 January 2017
Published Online 09 March 2017
Corresponding Author Susana Rodríguez-Couto – srodriguez@ceit.es
Abstract

White-rot-fungi (WRF) are the only organisms able to degrade the whole wood components (i.e. lignin, cellulose and hemicellulose). This ability is due to the secretion of extracellular non-specific ligninolytic enzymes during their secondary metabolism usually triggered by nutrient exhaustion. The non-specificity of these enzymes enables them to transform a great variety of recalcitrant and hazardous pollutants such as polycyclic aromatic hydrocarbons (PAHs), pesticides, fuels, alkanes, polychlorinated biphenyls (PCBs), explosives and synthetic dyes. In addition, their extracellular nature allows WRF to access non-polar and insoluble compounds. This makes WRF very appealing for their application to different industrial and biotechnological processes. Also, new potential commercial products and processes from the fungal treatment of lignocellulosic materials may arise. The implementation of such applications would contribute to the establishment of a more sustainable industry and the development of a circular economy.

Keywords biotechnology – degradation – lignin – ligninolytic enzymes – valorisation
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Article Number 8
Title

Biological management of fusarium wilt of tomato using biofortified vermicompost

Authors

Basco MJ, Bisen K, Keswani C, Singh HB

Received 17 December 2015
Accepted 25 March 2017
Published Online 09 March 2017
Corresponding Author H.B.Singh – hbs1@rediffmail.com
Abstract

Fusarium wilt of tomato caused by Fusarium oxysporum f. sp. lycopersici is a serious problem limiting tomato production worldwide. Biological control has emerged as one of the most promising alternatives to the chemical fungicides. Biological management of Fusarium wilt of tomato using vermicompost biofortified with selected biological control agents (BCAs) i.e. Trichoderma harzianum, Pseudomonas fluorescens and Bacillus subtilis was the hypothesis of this study. In vitro test showed that all the selected microbes were antagonistic to F. oxysporum f. sp. lycopersici. The levels of different antioxidants, different plant growth parameters and incidence of disease were recorded at different time intervals in designed treatments. According to the experimental results, significant variations in reduction of disease incidence, enhancement in plant growth, yield and as well as higher stimulation of antioxidants were observed in tomato plants treated with biofortified vermicompost as compared to the control. Maximum values were recorded in plants treated with T. harzianum fortified vermicompost.

Keywords Biocontrol agents – biological management – biofortified vermicompost – Fusarium wilt-tomato
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About Mycosphere

Mycosphere publishes reviews, research articles, methodology papers, taxonomic works such as monographs, and checklists which are relevant to fungal biology, including lichens. The official journal language is English.

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