Increasing photosynthetic productivity of cereal bioenergy crops as affected by the water content in leaves under mycorrhization of the root system

Purpose. To determine photosynthetic productivity of miscanthus gigantheus and switchgrass as affected by leaf water content under mycorrhization of their roots. Methods. Field, laboratory, and statistical. Results. The obtained results indicate that the use of vesicular-arbuscular mycorrhizal (VAM) preparations Mycofriend (fungus Trichoderma harzianum RIFAI.), Mikovital (fungus Tuber melanosporum VITTAD.), and nitrogen-fixing preparation Florobacillin (Bacillus subtilis Cohn.) helps to increase water content in the leaves of such cereal bioenergy crops as miscanthus gigantheus and switchgrass. In particular, in all vegetation periods, in the treatments with Mycofriend, the water content in miscanthus gigantheus leaves was higher by 11.2–20.1% than in the control, while in switchgrass it was higher by 16.9–20.5% than in the control. In the treatments with Mikovital and Florobacillin, leaf water content ranged in miscanthus from 7.1 to 15.6% and from 5.8 to 11.7%, respectively, and in switchgrass, from 11.6 to 14.7% and from 7.0 to 10.2%, respectively. The photosynthetic productivity of these crops is affected by the water content in the leaves. There is a close correlation between these factors (correlation coefficient 0.95–0.96). Conclusions. Root application of biological plant products Mycofriend, Mikovital and Florobacillin improves water content in the leaves of cereal bioenergy crops, such as miscanthus gigantheus and switchgrass, and increases their photosynthetic productivity.

Investigation of the Proteomes of the Truffles Tuber albidum Pico, T. aestivum, T. indicum, T. magnatum, and T. melanosporum

Truffles of the Tuber species are known as expensive foods, mainly for their distinct aroma and taste. This high price makes them a profitable target of food fraud, e.g., the misdeclaration of cheaper truffle species as expensive ones. While many studies investigated truffles on the metabolomic level or the volatile organic compounds extruded by them, research at the proteome level as a phenotype determining basis is limited. In this study, a bottom-up proteomic approach based on LC-MS/MS measurements in data-independent acquisition mode was performed to analyze the truffle species Tuber aestivum, Tuber albidum Pico, Tuber indicum, Tuber magnatum, and Tuber melanosporum, and a protein atlas of the investigated species was obtained. The yielded proteomic fingerprints are unique for each of the of the five truffle species and can now be used in case of suspected food fraud. First, a comprehensive spectral library containing 9000 proteins and 50,000 peptides was generated by two-dimensional liquid chromatography coupled to tandem mass spectrometry (2D-LC-MS/MS). Then, samples of the truffle species were analyzed in data-independent acquisition (DIA) proteomics mode yielding 2,715 quantified proteins present in all truffle samples. Individual species were clearly distinguishable by principal component analysis (PCA). Quantitative proteome fingerprints were generated from 2,066 ANOVA significant proteins, and side-by-side comparisons of truffles were done by T-tests. A further aim of this study was the annotation of functions for the identified proteins. For Tuber magnatum and Tuber melanosporum conclusive links to their superior aroma were found by enrichment of proteins responsible for sulfur-metabolic processes in comparison with other truffles. The obtained data in this study may serve as a reference library for food analysis laboratories in the future to tackle food fraud by misdeclaration of truffles. Further identified proteins with their corresponding abundance values in the different truffle species may serve as potential protein markers in the establishment of targeted analysis methods. Lastly, the obtained data may serve in the future as a basis for deciphering the biochemistry of truffles more deeply as well, when protein databases of the different truffle species will be more complete.

Biochemical and Health Properties of Truffles

Truffles are the most expensive edible mushrooms refer to genus tuber which grows symbiotically in plant roots such as oaks and hazels. Truffles are underground mushrooms also known for their characteristic earthy flavor which is the major reason for their special place in the culinary. Their characteristic intense aroma helps them in reproduction by attracting small animals. Truffles can survive in a wide range of environments such as deep forests as well as deserts. The most expensive varieties of truffles include Tuber melanosporum (Black truffle), Tuber magnatum (White truffle), Tuber aestivum (Burgundy truffle), Tirmania nivea, and Terfezia chlaveryi (Dessert truffles). Truffles vary in their composition and flavor profile from species to species. The major volatile components which are responsible for truffle aroma are aldehydes, ketones, sulfur compounds, alcohols, and esters. Truffles are highly nutritious, rich in antioxidants, and have therapeutic properties such as antimicrobial activity, antiviral activity, antimutagenic activity, anti-inflammatory activity, hepatoprotective activity, etc. The major active components present in truffle are tuberoside, phenolics, anandamide, and ergosterol.

Increased Extracellular Saponin Production After the Addition of Rutin in Truffle Liquid Fermentation and Its Antioxidant Activities

Saponins possess a variety of pharmacological effects and exhibit great potential in the food industry as bioactive substances. In this study, extracellular saponin production via the liquid fermentation of Tuber melanosporum occurred with the addition of rutin. For this purpose, medium composition and culture conditions were optimized using single-factor experiments and an orthogonal experiment design. The optimal medium consisted of glucose (43.5 g/L), peptone (6 g/L), KH2PO4 (1.15 g/L), NaCl (0.2 g/L), vitamin B2 (0.082 g/L), vitamin B6 (0.1 g/L), vitamin C (0.02 g/L), and rutin (4.8 g/L). The culture conditions were as follows: 12.5% (v/v) inoculation, medium volume of 50 mL/250 mL flask, culture temperature of 24 °C, shaker speed of 190 rpm, initial pH of 5.7, and culture time of 96 h. Finally, a maximal extracellular saponin content of 0.413 g/L was obtained, which was 134.7% higher than that in the base medium. Rutin proved to be an excellent promoter, because the saponin production was increased by 50.2% compared to that in the optimized medium without rutin. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, hydroxyl radical scavenging activity, and ferric reducing antioxidant power of truffle saponins reached 94.13%, 79.26%, and 42.22 mM, respectively. This study provides a useful strategy for fungal bioactive saponin production by liquid fermentation with the addition of flavonoid compounds.

Вплив мікоризного гриба Tuber Melanosporum на біорізноманіття мікроміцетів ризосфери та ріст і продуктивність фундука

Наявність мікоризи є чинником ефективного процесу депонування вуглецю в екосистемі. Різні способи мікоризації сприяють ефективному росту та продуктивності рослин. Вивчено вплив Tuber melanosporum IMB F-100106 у складі препарату "Міковітал" на ріст, розвиток та продуктивність фундука сорту 'Шедевр'. Досліджено вплив різних способів внесення мікоризного препарату на ріст та розвиток фундука: замочування коренів, краплинного зрошення та підживлення. Зафіксовано, що діаметр кореневої шийки зріс на 10,2 %, кількість основних коренів збільшилась на 12,2 % та довжина кореневої системи – на 13,9 %. Відзначено також зростання загальної кількості листків на 14,0 %, довжини річного приросту – на 14,4 % та висоти саджанців – на 12,9 %. Кореневе підживлення 2-5 %-ми розчинами препарату забезпечило підвищення рівнів урожайності фундука до 21,7-22,4 ц/га з отриманням прибавки урожаю на 10,2-13,7 %. Важливими показниками для горіхоплідних рослин є хімічний склад плодів та їх дегустаційне оцінювання. Кореневе підживлення 2-5 %-м розчином препарату забезпечило зростання в них вмісту жиру на 1,5-2,7 %, а також призвело до збільшення виходу ядра на 6,0-6,9 %. Дегустаційна оцінка плодів підвищилась на 0,3-0,4 бали. Здійснено мікологічний аналіз 150 зразків ґрунту ризосфери фундука та ґрунту цілинних земель. Виділено 475 ізолятів мікроміцетів, що належать до 124 видів мікроскопічних грибів. Наведено 48 видів мікроскопічних грибів різних таксономічних груп, які найчастіше траплялись у досліджуваних ґрунтах. Встановлено, що мікофлора ризосфери мікоризованого та немікоризованого фундука істотно відрізняється за видовим складом. Індекси видового різноманіття мікроміцетів свідчать, що найрізноманітніший видовий склад мікобіоти характерний для ризосфери мікоризованого фундука. Характерною особливістю мікроміцетного складу ризосфери мікоризованого фундука є зменшення чисельності та видового різноманіття патогенів. Проаналізовано місткість екосистеми фундукового саду, тобто здатність створювати умови існування для популяцій різних видів, зокрема мікроміцетів ґрунту. Визначено роль технології регенеративного землекористування, яку успішно впроваджують в Україні на рівні лісгоспів, малих і середніх фермерських господарств, холдингів. Вона може стати основою Продовольчого Суверенітету нашої країни і дасть змогу Україні розвиватися за своїм унікальним планом: зберегти для прийдешніх поколінь здорове довкілля і годувати населення якісними органічними продуктами харчування.

Mycorrhization of Quercus Mongolica Seedlings by Tuber Melanosporum Alters Root Carbon Exudation and Rhizosphere Bacterial Communities

Aims To study how ectomycorrhizas (ECMs) mediate plant performance and rhizosphere soil bacterial communities via altered physiological characteristics and root carbon exudation. Methods Tuber melanosporum-colonized and uncolonized Quercus mongolica seedlings were grown on a substrate consisting of 41 % peat, 41 % pumice, 9 % pine bark and 9 % lime. Gas exchange fluorescence system, inductively coupled plasma atomic-emission spectrometer, high-performance liquid chromatography, gas chromatography and mass spectrometry, and 16S rRNA sequencing were used to analyze photosynthetic and nutritional characteristics, and rhizosphere carbon exudates, and bacterial communities. Results Tuber melanosporum mycorrhization increased leaf photosynthetic rate (by 69 %) and phosphorus concentration (94 %); increased rhizosphere pH (0.4 units), total organic carbon (TOC, 76 %) and acid phosphatase activity (33 %); but decreased leaf potassium concentration (26 %) and rhizosphere organic anions (50 %). Additionally, sugars like galactose were present in rhizosphere extract of colonized, but not uncolonized seedlings. Mycorrhization altered rhizosphere bacterial communities, with only ~10 % operational taxonomic units (OTUs) shared by both colonized and uncolonized seedlings; T. melanosporum enriched the phylum actinobacteria and the OTU of amb-16S-1323, IMCC26256 and PLTA13, but reduced SWB02. The abundances of different OTUs were differently affected by T. melanosporum colonization, and they were correlated with different physiological and/or rhizosphere factors. Conclusion Our results demonstrate that T. melanosporum ECM colonization can regulate carbon economy and rhizosphere bacterial communities of Q. mongolica seedlings grown in a previously sterilized peat-based substrate, to promote plant growth and nutrient cycling.

Mulch removal time did not have significant effects on Tuber melanosporum mycelium biomass

Aim of study: We aimed to i) evaluate the effects of mulching on Tuber melanosporum mycelium biomass and seedling growth (i.e. root collar diameter and seedling height) and ii) unravel the relationship between growth in root collar diameter and mycelium abundance, in a T. melanosporum plantation.Area of study: The experimental plantation is located in the Pre-Pyrenees mountains in Catalonia, Spain.Material and methods: The experimental plantation was established in 2010 using one-year-old T. melanosporum inoculated Quercus ilex seedlings. Double-layered mulch materials were placed around the seedlings. The mulch materials were removed from randomly selected seedlings in 2015 and 2018. Soil samples were collected in 2018 at 40 and 80 cm distances from seedlings that had mulching during five and eight years, and T. melanosporum mycelium biomass was estimated by quantitative Polymerase Chain Reaction (qPCR). Seedling root collar diameter and height were measured simultaneously when mulch materials were removed.Main results: Mulch removal time did not have significant effects on T. melanosporum mycelium biomass or seedling growth. However, mycelium biomass at 40 cm distance tended to be higher on seedlings after eight-year mulching with 0.9 mg/g soil whereas mycelium biomass was 0.4 mg/g soil after five-year mulching. A positive relationship between mycelium biomass and seedling root collar diameter was also found.Research highlights: Mulching seems to have a positive effect on truffle mycelium biomass, with nearly two times higher quantity of mycelium after eight-years compared with five-years mulching usage. Seedling root collar diameter is a good indicator of mycelium expansion in the plantation.Keywords: Black truffle; Quercus ilex; mulching; tree growth; truffle cultivation.