Avellana Research Articles

An effective chromatographic fingerprinting workflow based on comprehensive two-dimensional gas chromatography – Mass spectrometry to establish volatiles patterns discriminative of spoiled hazelnuts (Corylus avellana L.)

The volatile fraction of hazelnuts encrypts information about: cultivar/geographical origin, post-harvest treatments, oxidative stability and sensory quality. However, sensory features could be buried under other dominant chemical signatures posing challenges to an effective classification based on pleasant/unpleasant notes. Here a novel workflow that combines Untargeted and Targeted (UT) fingerprinting on comprehensive two-dimensional gas-chromatographic patterns is developed to discriminate spoiled hazelnuts from those of acceptable quality. By flash-profiling, six hazelnut classes are defined: Mould, Mould-rancid-solvent, Rancid, Rancid-stale, Rancid-solvent, and Uncoded KO. Chromatographic fingerprinting on composite 2D chromatograms from samples belonging to the same class (i.e., composite class-images) enabled effective selection of chemical markers: (a) octanoic acid that guides the sensory classification being positively correlated to mould; (b) ƴ-nonalactone, ƴ-hexalactone, acetone, and 1-nonanol that are decisive to classify OK and rancid samples; (c) heptanoic and hexanoic acids and ƴ-octalactone present in high relative abundance in rancid-solvent and rancid-stale samples.

Corylus avellana L. Husks an Underutilized Waste but a Valuable Source of Polyphenols

Bioactive potential of hazelnut husks was determined as a function of their cultivar source and extraction solvent. Hazelnut husks from four hazelnut cultivars (Butler, Grada de Viseu, Lansing and Morell) were picked in a hazelnut orchard at harvest and extracted with five solvents with different polarity: water, methanol, acetone, ethyl acetate and hexane. Phenolics were identified by HPLC–DAD and antioxidant activity was determined by three complementary methods: DPPH, FRAP and inhibition of lipid peroxidation. A total of 11 phenolics were identified in studied cultivars and grouped in five main classes namely, ellagitannin (ellagic acid), benzoic acids (gallic acid, protocatechuic acid and vanillic acid), flavonols (kaempferol-3,7-O-diglucoside, kaempferol-3-O-[6-acetylglucoside]-7-O-glucoside, kaempferol-3-O-[6acetylglucoside]-7-O-rhamnoside and quercetin-3-O-rutinoside), flavone (luteolin-7-O-rutinoside) and flavan-3-ol (epicatechin). Cultivar and extraction solvent influenced significantly (p < 0.001) the extraction yield. ‘Grada de Viseu’ husks presented the highest content of individual phenolics identified, particularly in methanol extracts whilst ‘Lansing’ showed the lowest levels. Similar pattern was found for antioxidant activities. Methanolic husk extracts exhibited the greatest antioxidant potentials followed by water and acetone. The valorization of hazelnuts by-products gives an important contribution for the isolation and purification of bioactive molecules that can be used for both medicinal and industrial purposes.

Chilling and Forcing From Cut Twigs-How to Simplify Phenological Experiments for Citizen Science.

Low-cost phenological experiments with cut twigs are increasingly used to study bud development in response to spring warming and photoperiod. However, a broader variety of species needs to be tackled and in particular the influence of insufficient winter chilling deserves more attention. Therefore, we investigated if and how chilling requirements can be efficiently investigated by cut twigs and how this low-tech approach could be successfully implemented as a citizen science or school project. We conducted an experiment on bud burst and leaf development of Corylus avellana L. twigs, with natural chilling outdoors on a shrub (S) and another chilling treatment as cut twigs in containers (C), and subsequent forcing indoors. Subsampling of the number of cutting dates and number of twigs was used to infer minimum required sample sizes. Apart from insufficiently chilled twigs, ~80% of the twigs (both S and C) reached leaf out. For multiple definitions of chilling and forcing, a negative exponential relationship was revealed between chilling and amount of forcing needed to reach certain developmental stages. At least 5 out of 15 cutting dates or alternatively half of the 10 twig repetitions, but especially those mirroring low chilling conditions, were needed to describe the chilling-forcing relationship with some degree of robustness. In addition, for cutting dates with long chilling, i.e., from January onwards, freshly cut twigs (S) required significantly more forcing to reach bud burst than twigs from containers (C), although the effect was small. In general, chilling conditions of mature shrubs were well captured by cut twigs, therefore opening the possibility of chilling through refrigeration. We conclude that experimental protocols as outlined here are feasible for citizen scientists, school projects, and science education, and would have the potential to advance the research field if carried out on a large scale. We provide an easy-to-use Shiny simulation app to enable citizen scientists to build up a bud development model based on their own experimental data and then simulate future phenological development with winter and/or spring warming. This may encourage them to further study other aspects of climate change and the impacts of climate change.

Use of chinese hazel (Corylus chinese French.) in hazelnut breeding (Corylus domestica Kos. st Opal.)

Aim. The need to improve the domestic assortment of hazelnuts and encouraging results obtained due to the involvement of Chinese hazel Corylus chinensis Franch. in hybridization with the best of its cultivars, prompted the research. Methods. The hybridization program included the most adapted to the conditions of Ukraine domestic and foreign cultivars of hazelnuts, as well as pollinators from natural populations of Corylus avellana L. and Corylus chinensis. Isolation of maternal and collection of pollen from paternal components of crossing was made using standard methods. Pollination was made by blowing pollen into bags with a medical insufflator MO-03 with a special needle (without removing the bag) and after 2–3 days, the pollination was repeated. Hybrid nuts were sown in autumn with wrappers without stratification. Other operations for growing seedlings and further maintenance were performed according to the standard methods. Results. Sufficiently high levels of fruit binding in variants with C. avellana pollen confirm the genetic proximity of the studied cultivars to this species, and the indicators from pollination by C. chinensis were 3–5 times lower. They confirm the remoteness of Chinese hazel from the modern cultivar assortment, but they make it possible to use this species in the hazelnut breeding. Thanks to this, a valuable material was created from which a new cultivar Sofiyvsky 15 was selected. It entered fruiting in the third year after crossing and combines high potential productivity with adaptability, a spherical shape of the fruit and a high content of raw protein and oil in them. Conclusions. The ‘Sofiyivsky 15’ has significantly exceeded the ‘Halle’ and the conditional standard due to its adaptability, quickness, processability and quality of nuts. It can be recommended for wide introduction in farms of all agro-climatic zones of Ukraine.&#x0D; Keywords: Corylus chinensis Franch., Corylus spp., cultivar Sofiyivsky 15, hazelnut hybrids, hybrid orchard, interspecific crossing.

Modeling of paclitaxel biosynthesis elicitation in Corylus avellana cell culture using adaptive neuro-fuzzy inference system-genetic algorithm (ANFIS-GA) and multiple regression methods.

Paclitaxel as a microtubule-stabilizing agent is widely used for the treatment of a vast range of cancers. Corylus avellana cell suspension culture (CSC) is a promising strategy for paclitaxel production. Elicitation of paclitaxel biosynthesis pathway is a key approach for improving its production in cell culture. However, optimization of this process is time-consuming and costly. Modeling of paclitaxel elicitation process can be helpful to predict the optimal condition for its high production in cell culture. The objective of this study was modeling and forecasting paclitaxel biosynthesis in C. avellana cell culture responding cell extract (CE), culture filtrate (CF) and cell wall (CW) derived from endophytic fungus, either individually or combined treatment with methyl-β-cyclodextrin (MBCD), based on four input variables including concentration levels of fungal elicitors and MBCD, elicitor adding day and CSC harvesting time, using adaptive neuro-fuzzy inference system (ANFIS) and multiple regression methods. The results displayed a higher accuracy of ANFIS models (0.94–0.97) as compared to regression models (0.16–0.54). The great accordance between the predicted and observed values of paclitaxel biosynthesis for both training and testing subsets support excellent performance of developed ANFIS models. Optimization process of developed ANFIS models with genetic algorithm (GA) showed that optimal MBCD (47.65 mM) and CW (2.77% (v/v)) concentration levels, elicitor adding day (16) and CSC harvesting time (139 h and 41 min after elicitation) can lead to highest paclitaxel biosynthesis (427.92 μg l-1). The validation experiment showed that ANFIS-GA method can be a promising tool for selecting the optimal conditions for maximum paclitaxel biosynthesis, as a case study.

Morphological Traits and Chemical Composition of Hazelnut from Different Geographical Origins: A Review

Hazelnut (Corylus avellana L.) is a popular tree nut worldwide, and in recent years, the production of hazelnuts has increased in many countries due to large investments improving agricultural techniques and the selection of new cultivars. Turkey, the leader of global hazelnut production, has shown that supply can strongly fluctuate, which leads to peak prices and market instability. In this review, an overview of the morphological traits, nutritional value, fatty acid composition, tocopherols, and future prospects of hazelnut production are described. Furthermore, information regarding hazelnuts from different geographical origins (Chile, Croatia, Iran, Italy, Oregon (US), Poland, Portugal, Serbia, Spain, and Turkey; total of 22 cultivars) to enhance the utilization of hazelnut cultivars from newly producing orchards and origins is comprehensively summarized.

A new genus of Bambusicolaceae (Pleosporales) on Corylus avellana (Fagales) from Italy.

BackgroundIn this study, we introduce Corylicola gen. nov. in the family of Bambusicolaceae (Pleosporales), to accommodate Corylicola italica sp. nov. The new species was isolated from dead branches of Corylus avellana (common hazel) in Italy. The discovery of this new genus with both sexual and asexual characters will contribute to expand the knowledge and taxonomic framework of Bambusicolaceae.New informationCorylicola gen. nov. has similar morphological characters compared to other genera of Bambusicolaceae. These are solitary, scattered, globose to subglobose and ostiolate ascomata; anastomosing and branching pseudoparaphyses; cylindrical asci with a well-developed ocular chamber and short furcate pedicel; and single-septate ascospores. The coelomycetous asexual morph of Corylicola has holoblastic, phialidic conidiogenous cells and light brown conidia analogous to other members in the family. Corylicola differs from the other genera of Bambusicolaceae in having yellowish-brown ascospore masses at the top of the ascomatal neck. Detailed morphological illustrations with comprehensive descriptions for the new taxa are provided, as well as a key to the genera of Bambusicolaceae. Maximum Likelihood analysis and Bayesian Inference of a combined SSU, LSU, ITS, RPB2 and TEF1 sequence dataset confirms the placement of this genus as a distinct lineage in Bambusicolaceae.

Persistence of Tuber melanosporum in truffle orchards in North Carolina, USA.

A survey was conducted to determine the persistence of mycorrhization by Tuber melanosporum in truffle orchards established with European and American species of oak and common hazel trees in North Carolina. The trees had reportedly been inoculated and colonized by T. melanosporum prior to planting. Root samples were collected from 95 trees among seven orchards in 2015 and roots were analyzed by morphology and quantitative PCR. Samples that tested negative for T. melanosporum or where ectomycorrhizal morphology was not observed were analyzed by sequencing to identify the mycorrhizal fungal symbiont present. The presence of T. melanosporum was detected in all seven orchards. In six orchards, T. melanosporum was detected on all trees, but in only two of fifteen trees in one orchard. Other species of Tuber including T. brennemanii, T. canaliculatum, and T. lyonii, species of Scleroderma, and members of the Pezizales were also detected by sequence analysis. Sporocarps of T. aestivum and T. brumale were found in 2017 and 2018 in separate orchards in North Carolina after the survey was conducted. Overall, results indicate that T. melanosporum has persisted in truffle orchards sampled in North Carolina. Indigenous and contaminating fungal species, including Tuber species, were also detected and present a challenge to the truffle industry in North Carolina.

Mathematical Modeling of Growth and Paclitaxel Biosynthesis in Corylus avellana Cell Culture Responding to Fungal Elicitors Using Multilayer Perceptron-Genetic Algorithm.

Paclitaxel is the top-selling anticancer medicine in the world. In vitro culture of Corylus avellana has been made known as a promising and inexpensive strategy for producing paclitaxel. Fungal elicitors have been named as the most efficient strategy for enhancing the biosynthesis of secondary metabolites in plant cell culture. In this study, endophytic fungal strain HEF17 was isolated from C. avellana and identified as Camarosporomyces flavigenus. C. avellana cell suspension culture (CSC) elicited with cell extract (CE) and culture filtrate (CF) derived from strain HEF17, either individually or combined treatment, in mid and late log phase was processed for modeling and optimizing growth and paclitaxel biosynthesis regarding CE and CF concentration levels, elicitor adding day, and CSC harvesting time using multilayer perceptron-genetic algorithm (MLP-GA). The results displayed higher accuracy of MLP-GA models (0.89–0.95) than regression models (0.56–0.85). The great accordance between the predicted and observed values of output variables (dry weight, intracellular, extracellular and total yield of paclitaxel, and also extracellular paclitaxel portion) for both training and testing subsets supported the excellent performance of developed MLP-GA models. MLP-GA method presented a promising tool for selecting the optimal conditions for maximum paclitaxel biosynthesis. An Excel® estimator, HCC-paclitaxel, was designed based on MLP-GA model as an easy-to-use tool for predicting paclitaxel biosynthesis in C. avellana CSC responding to fungal elicitors.

Palaeoecological response to Greenlandian (Early Holocene) climatic changes: Insight from an abandoned-channel sequence of the Meuse River at Autrecourt-et-Pourron (Ardennes, France)

A Greenlandian (Early Holocene) palaeochannel of the Meuse River is described from Autrecourt-et-Pourron in the Ardennes region of northern France. During the Younger Dryas, fluvial deposits represent a high-energy, sinuous palaeochannel, but at the onset of the Holocene, progressive channel abandonment resulted in the establishment of a low-energy meandering river system. Well-dated studies using palynology, carpology, malacology and geomorphology reveal a Greenlandian succession of changes in fluvial dynamics and vegetation. Between 11,700 and 11,400 cal yr BP, warmer temperatures led to the development of a birch community (Betula sp.) within an open grassland, dominated by herbaceous cold-adapted plants (Linum alpinum, Plantago montana, Artemisia sp., Juniperus sp.). Between 11,400 and 11,100 cal yr BP, the river and the vegetation dynamics reflected two short-term climate events. Around 11,400 cal yr BP, the palaeochannel became separated from the active channels of the Meuse River but remained dominated by waterlogged wetlands. This cold and wet phase represents the “Preboreal Oscillation” also referred as the “11.4 ka event”. Around 11,300 cal yr BP, the records suggest that fire frequency increased close to the channel, and may indicate a dry episode that reflects a sharp, short-lived rise in temperature. Between 11,100 and 10,700 cal yr BP (Late Preboreal phase), the channel received flood deposits again. Salix and helophytes developed while Populus colonised the riverbank. From 10,700 cal yr BP, at the beginning of the Boreal phase, the palaeochannel was finally abandoned and dense temperate woodland with Corylus avellana and Quercus spp. became established. Based on its high chronological resolution, Autrecourt-et-Pourron represents a key locality in north-western Europe to investigate environmental change in connection with Early Holocene short climate variations. In addition, the results highlight the valuable contribution of carpological analyses in improving the spatial resolution of reconstructions of vegetation cover.

Discovery of simple sequence repeat (SSR) markers in hazelnut (Corylus avellana L.) by transcriptome sequencing and SSR-based characterization of hazelnut cultivars

ABSTRACT Current cultivation and breeding strategy based on selections from local and wild vegetation does not meet the hazelnut demand. This situation would benefit from the development of high-yielding cultivars with greater tolerance to abiotic and biotic stress conditions. Molecular markers are useful tools to support these breeding efforts. In the current study, EST-SSR markers were developed from RNA-sequencing data obtained from three hazelnut varieties. The transcriptome sequences contained 86,542 unigenes and a total of 25,391 SSRs, most of which (50.9%) were di-nucleotide repeats. A set of 40 primer pairs were randomly selected to validate their usefulness for investigating genetic diversity in 19 C. avellana cultivars and one accession of Corylus colurna. Of the 40, 28 were highly polymorphic with average values of observed heterozygosity, polymorphism information content and number of alleles per locus of 0.45, 0.67 and 6.11, respectively. The principal coordinate and dendrogram analysis separated the C. colurna accession from the C. avellana cultivars, and separated the cultivars for date of leaf bud burst. These new EST-SSRs and others that could be developed from the transcriptome sequences increase the number of markers for cultivar fingerprinting and may be useful for identifying marker-trait associations and further genetic diversity analyses.

Natural Variation of Hazelnut Allergenicity: Is There Any Potential for Selecting Hypoallergenic Varieties?

Hazelnuts (Corylus avellana L.) have an important role in human nutrition and health. However, they are a common cause of food allergy. Due to hazelnut varietal diversity, variety-dependent differences in the IgE-binding properties may be suspected, which could allow therapeutic strategies based on the use of hypoallergenic varieties to induce desensitization. In a proteogenomic approach, we aimed to evaluate the allergenic potential of a genetically diverse set of hazelnuts (n = 13 varieties). Minor differences were found at the level of genes encoding important allergens, namely Cor a 8, Cor a 9, and Cor a 14. Nevertheless, IgE-reactivity was similar for all varieties using sera from seven allergic individuals. The predominant IgE-reactive proteins were Cor a 9 (100%) and Cor a 1.04 (60%), with the former being the most frequently identified by a two-dimensional gel electrophoresis (2-DE)-based proteomic approach. Therefore, it seems that the conventional exclusion diet will hold its ground for the time being.

A Genetic and Metabolomic Perspective on the Production of Indole-3-Acetic Acid by Pantoea agglomerans and Use of Their Metabolites as Biostimulants in Plant Nurseries.

The species Pantoea agglomerans includes strains that are agronomically relevant for their growth-promoting or biocontrol traits. Molecular analysis demonstrated that the IPDC pathway involved in the conversion of tryptophan (Trp) to indole-3-acetic acid (IAA) is highly conserved among P. agglomerans strains at both gene and protein levels. Results also indicated that the promoter region controlling the inducible expression of ipdC gene differs from the model system Enterobacter cloacae, which is in accordance with the observation that P. agglomerans accumulates higher levels of IAA when cells are collected in the exponential phase of growth. To assess the potential applications of these microorganisms for IAA production, P. agglomerans C1, an efficient auxin-producer strain, was cultivated in 5 L fermenter so as to evaluate the effect of the medium formulation, the physiological state of the cells, and the induction timing on the volumetric productivity. Results demonstrated that higher IAA levels were obtained by using a saline medium amended with yeast extract and saccharose and by providing Trp, which acts both as a precursor and an inducer, to a culture in the exponential phase of growth. Untargeted metabolomic analysis revealed a significant effect of the carbon source on the exometabolome profile relative to IAA-related compounds and other plant bioactive signaling molecules. The IAA-enriched metabolites secreted in the culture medium by P. agglomerans C1 were used as plant biostimulants to run a series of trials at a large-scale nursery farm. Tests were carried out with in vitro and ex vitro systems following the regular protocols used for large-scale plant tree agamic propagation. Results obtained with 4,540 microcuttings of Prunus rootstock GF/677 and 1,080 plantlets of Corylus avellana L. showed that metabolites from strain C1 improved percentage of rooted-explant, number of adventitious root formation, plant survival, and quality of plant as vigor, with an increase in the leaf area between 17.5 and 42.7% compared to IBA-K (indole-3-butyric acid potassium salt)–treated plants.

Advances in cultivar choice, hazelnut orchard management, and nut storage to enhance product quality and safety: an overview.

European hazelnut (Corylus avellana L.) is a major species of interest for nutritional use within the Betulaceae family and its nuts are widely used throughout the world in the chocolate, confectionery, and bakery industries. Recently its cultivation has been expanded in traditional producer countries and established in new places in the southern hemisphere, including Chile, South Africa, and Australia. Introducing hazelnut in new environments could reduce its productivity, lead the trees to experience eco-physiological disorders, and expose the crop to high pressure from common and new pests and diseases. Thus, new approaches in cultivar choice guidance, in the sustainable orchard management and even in nut storage and kernel quality evaluation are urgently required to improve the hazelnut production and processing chain. The main objective of this study was to systematize the published information regarding recent findings about the cultural operations that directly influence nut and kernel quality, support varietal choice for new plantations, and list the recent advances in nut storage and in quality and safety evaluation. © 2020 Society of Chemical Industry.

Research, Innovation and Development on Corylus avellana through the Bibliometric Approach

ABSTRACT Among the dried fruits, hazelnut cultivation represents one of the greater world productions. Based on this consideration, it has been decided to verify whether the great commercial importance of this fruit corresponds to an equally dynamic and productive scientific activity. The aim of this study is to analyze the network structure and the conceptual evolution of research on Corylus avellana through time. A scientific mapping approach was used and applied to a set of scientific publications from 1980 to 2019, retrieved from the Scopus database. From this period, the Scopus search provided 861 documents. During the 1980–1999 period, research topics were poorly characterized, but better defined in the 2000–2019 period. From 2000 to 2009, the research focused on three distinct areas of interest: (i) genetic techniques aimed at the study and resolution of phytosanitary problems; (ii) genetic improvement of new cultivars in order to obtain production quality; (iii) open-field cultivation techniques to improve the quantity of hazelnut production and the quality of the product. In the last decade (2010–2019), genetic improvement techniques, both in the laboratory and in the field, have merged into a single cluster using the most innovative molecular biology techniques. At the same time, the cultivation techniques were oriented not only toward production in the field, but also at studying and improving the quality of the products. Through the analysis was possible to trace some future lines of scientific research for this relatively unexplored topic.

First report of Erysiphe corylacearum on Corylus avellana and C. colurna in Austria

In September 2020, prominent powdery mildew disease symptoms were seen on leaves of Corylus avellana (hazelnut) and C. colurna (Turkish hazelnut) at several localities in eastern and southern Austria (Burgenland, Carinthia, Lower Austria, Styria, Vienna). The symptoms differed from those previously observed (caused by Phyllactinia guttata) by mycelia on the upper leaf surface and by smaller chasmothecia with branched appendices. The disease was observed on Corylus spp. growing in mixed deciduous forests, hedges as well as city gardens and parks. Disease symptoms started as small spots of white, amphigenous surface mycelium, that radially enlarged to form effuse patches reaching up to 2 cm in diameter, eventually becoming confluent and then covering the entire leaf surface (Figs. 1, 2). Infections on the lower leaf surface caused chlorotic spots on the upside (Fig. 1). Upon severe infection, leaves were distorted (Figs. 1, 2). On surface mycelium, ellipsoid to doliiform conidia (27-36 × 18-23 μm) were produced singly on conidiophores (Fig. 3). In addition, dark brown chasmothecia, 70-120 μm in diameter were abundantly produced (Fig. 4), which had up to 15, 60-90 μm long, stiff, hyaline appendages with repeatedly dichotomously branched tips. They contained 2-6 broadly ellipsoid, mostly (3-)7-8 spored asci of 51-70 × 38-57 μm, with hyaline ascospores 19-28 × 13-18 μm (Fig. 5). Based on these characters, the powdery mildew was identified as Erysiphe corylacearum (Braun & Cook, 3). To confirm the morphological identification, the ITS-LSU of sample WU 43287 (Lower Austria, Gießhübl, host: Corylus avellana) was sequenced. DNA was extracted from chasmothecia using the innuPREP DNA Micro Kit (Analytik Jena, Germany) according to the manufacturer's instructions, with a lysis time of 16 hours. The ITS-partial LSU was amplified as a single stretch with primers V9G and LR5 and sequenced according to Voglmayr et al. (6). The obtained sequence was deposited in GenBank (Accession No. MW031866), and representative voucher specimens were deposited in the fungarium of the University of Vienna (WU 43287, WU 43421, WU 43423, WU 43424, WU 43514, WU 43515, WU 43520, WU 43525). A nBLAST analysis revealed 99-100% identity to sequences of E. corylacearum, with 100% identity to sequences from Azerbaijan (LC270863), Iran (MF668615, MH047243), Japan (MT095104), Switzerland (MN822721-MN822723) and Turkey (KY082910), confirming the species identification. Native to East Asia and probably North America, E. corylacearum was first observed in Turkey in 2013 and has since rapidly extended its distribution range to West Asia as well as Eastern and Central Europe (Beenken et al., 2; Heluta & Fokshei, 4). Erysiphe corylacearum has been reported as a severe invasive alien pathogen, causing significant yield losses in hazelnut orchards in Turkey, Iran and Georgia (Arzanlou et al., 1; Meparishvili et al., 5). The authors thank Christian Scheuer for information on a record from Styria.

In vitro rooting of hybrid hazelnuts (Corylus avellana×Corylus americana) in a temporary immersion system

Commercial micropropagation of hybrid hazelnuts (Corylus avellana L. × C. americana Marshall) has been limited, owing to their poor rooting ability in vitro as well as ex vitro, leading to high mortality of plantlets transplanted in the greenhouse. The objective of this study was to develop an efficient and cost-effective protocol for rooting and plantlet acclimation of in vitro grown hazelnut shoots. Efficient in vitro rooting was accomplished in a rocker-based temporary immersion bioreactor system. The use of a temporary immersion system (TIS) in combination with the inert substrate Oasis® In Vitro Express (IVE) significantly improved the in vitro rooting efficiency (100%) compared with semi-solid medium (27%) after four weeks of culture. A higher density (36 explants/vessel) of shoot explants in the TIS was found to support a significantly greater shoot height, chlorophyll content, and longest root length, compared with the lowest density treatment (12 explants/vessel). Efficiency of rooting and the number of roots formed were similar for both the high and low density of explants in the culture vessels, and the resulting plantlets exhibited &gt; 80% survival in the greenhouse. These results demonstrate the usefulness of rocker-based TIS for commercial micropropagation of hazelnuts and, potentially, other tree species.

First report of fungal complex causing grey necrosis of hazelnut in Chile

During the productive stage of Corylus avellana (hazelnut) in La Araucanía, Chile (October-December 2018-19) we observed symptoms consisting of a brown-greyish spot occurring at the bottom of the nut and enlarging upwards to the apex, and affecting around 30% of plants, mainly cv. Barcelona (Figs. 1-2). In severe infections the bracts were also affected. Symptoms were consistent with grey necrosis reported in hazelnut in Italy, and caused by a fungal complex formed mainly by Alternaria spp., Diaporthe spp.and Fusarium spp. (Belisario et al., 2). To isolate causal microorganisms from infected plants (35 plants, cv. Barcelona), small pieces of kernels and bracts were cut from the margin between diseased and healthy tissues and were observed by variable pressure scanning electron microscopy (Fig. 3). They were disinfected by immersion in 80% ethanol for 5 mins, followed by sodium hypochlorite (40 g/l) for 20 s, and rinsed 3 times with sterile distilled water. They were then placed onto potato dextrose agar (PDA) media (4 g potato extract, 20 g dextrose and 15 g agar per litre of sterile distilled water). Samples were maintained in the dark for five days. Thirty-five fungi isolated from infected tissues were transferred to PDA. Molecular identification was based on the sequencing of the ribosomal internal transcribed spacer 2 region (ITS2) amplified using primers fITS9 (5'-GAACGCAGCRAAIIGYG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') (Duran et al., 3). PCR products were purified and sequenced by Macrogen Inc. (Korea). BLAST analysis limited to type material showed 99.5-100% identities with five species: Fusarium sporotrichioides (GenBank Accession Nos. MF629821 and MF629827), Alternaria alternata (MF629825), Diaporthe sp. (MF629820 and MF629822) and its anamorph Phomopsis sp. (MF629824), and Neofusicoccum sp. (MF629823). Isolates were deposited in the Chilean Culture Collection of Type Strains with the codes: CCCT19.169 and CCCT19.170 (F. sporotrichioides); CCCT19.171 (A. alternata); CCCT19.172 and CCCT19.167 (Diaporthe sp.); CCCT19.173 (Phomopsis sp.); and CCCT19.166 (Neofusicoccum sp.). To test Koch's postulates, pathogenicity tests were performed on healthy hazelnut plants (one year old) in laboratory conditions at 25°C with natural daylight. Each fungus was first grown on PDA for seven days at 25°C. A 5 mm diameter disc was cut from the leading edge of the colony and placed separately, as well as together with other isolates, on individual, intact plant stems and wrapped in plastic film. For control plants, PDA without fungal growth was used. After one month disease symptoms were visible, while no symptoms appeared on the controls (Fig. 4). Fungi were consistently re-isolated from the plants onto PDA. We noted that Diaporthe sp. showed the highest disease incidence in the early stages. This was in contrast to Battilani et al. (1) who found a greater incidence in ripened nuts. This could be attributed to a variation in parameters such as rainfall which may affect dissemination and infection levels of Diaporthe sp. (Battilani et al., 1). Alternaria sp. showed the highest disease incidence in the latter stages, which was in accordance with Belisario & Santori (2) who defined this fungus as a secondary coloniser. To our knowledge, this is the first report of grey necrosis on hazelnut from Chile and control strategies are urgently required due to high economic losses reported in Europe (i.e. 30% in Italy). In addition F. sporotrichioides and A. alternata are highly active mycromycetes and are associated with mycotoxin production which is a human health risk (Lugauskas & Stakènienè, 4). This study was supported by CORFO-16PTECFS-66647; INACH RT_06-17, FONDECYT Regular 1209016. MEYS of the Czech Republic with co-financing from the EU (grant “KOROLID”, CZ.02.1.01/0.0/0.0/15_003/0000336).

Carbon Sequestration in Support of the “4 per 1000” Initiative Using Compost and Stable Biochar from Hazelnut Shells and Sunflower Husks

The achievement of carbon neutrality till 2050 will require the deployment of negative carbon emission technologies like the production and soil incorporation of biochar, produced from pyrolyzed plant-based residues. The carbon sequestration potential of biochar (BC) from hazelnut (Corylus avellana L.) shells (HNS) and sunflower (Helianthus annuus L.) husks (SFH) was evaluated when the biomass was carbonized in a fixed bed reactor, in a rotary kiln and in a screw reactor. In all tested reactors, higher temperatures (&gt;500 °C) and longer retention times increased the C concentration and stability of the biochar, with negligible effects of the reactor type and feedstock. A national case study was developed for Austria concerning the potential use of SFH- and HNS-BC in combination with compost for reaching the “4 per mille” objective. An annual soil organic carbon increase of 2.5 Mt C would be needed, requiring amendment rates of 2.2 Mt C a−1 for all annual crop areas and 0.3 Mt C a−1 for all vineyards and orchards. If compost only were used, the annual cost would be about 200 EUR ha−1 but short-term re-mineralization would have to be considered. If the more recalcitrant biochar were used only, about 2.3 t BC ha−1 would be needed at a cost of 1400–1870 EUR ha−1. The study shows in principle the feasibility of applying compost–biochar mixtures for achieving the “4 per mille” objective but in practice, supplemental soil management strategies for sequestering C will be required.

Molecular cloning and expression analysis of hybrid hazelnut (Corylus heterophylla×Corylus avellana) ChaSRK1/2 genes and their homologs from other cultivars and species.

The self-incompatibility system of Corylus is a sporophytic type that is phenotypically similar to that of Brassica. While the molecular mechanism of sporophytic self-incompatibility (SSI) has been investigated extensively in Brassica (Brassicaceae), little is known about the corresponding mechanism in Corylus (Betulaceae). Here, we discuss the SSI mechanism with respect to S-locus receptor kinase (SRK) gene homologs. To obtain two SRK candidate unigenes, we compared all of the unigenes in a transcriptional protein database from our previous study with BnSRK-1 (AB270767) using BLASTX with a cutoff e-value of 10-5. We then cloned the full-length cDNA of ChaSRK1 and ChaSRK2 genes from Ping'ou hybrid hazelnut (Corylus heterophylla×Corylus avellana) using RACE techniques. Bioinformatics approaches were used to analyze the cDNA sequences, protein sequences, and domains of the encoded proteins. The full-length ChaSRK1 cDNA was 2883 base pairs (bp) with a coding sequence (CDS) of 2,547bp encoding 849 amino acid residues. The full-length ChaSRK2 cDNA was 2,693bp, with a CDS of 2,433bp encoding 811 amino acids. The ChaSRK1/2 proteins contained an S-domain (extracellular domain), a transmembrane domain, a Ser/Thr protein kinase active site (kinase domain), and DUF3660 and/or DUF3403 domains. The lengths of 18 partial SRK homologs ranged from 1347 to 1451bp, and they contained the same structural domains as ChaSRK1 and ChaSRK2. Phylogenetic analysis revealed that all SRK homologs could be divided into two categories that were similar to the classification of SRKs in Brassica. The expression patterns of ChaSRK1 and ChaSRK2 differed: ChaSRK2 was predominantly expressed in mature stigmatic styles, while ChaSRK1 was expressed in other tissues with the highest in the root tips of Corylus. Using dual-color fluorescence in situ hybridization, ChaSRK1/2 expression was found to be localized in papillar cells. Collectively, these results revealed that SRKs from Corylus had similar characteristics to SRKs from Brassica. We therefore speculated that the SSI mechanism in Corylus might be more similar to the Brassica mechanism than to other SSI types.