Molecular Characterization and Genetic Variation in Ceratocystis fimbriata Ell. and Halst. on Pomegranate

Fifteen isolates of Ceratocystis fimbriata collected from different locations in Karnataka were characterized using ITS gene technology. It produced an amplification size of 600−650 bp, which indicated that all the isolates belong to the genus Ceratocystis, thus confirming the identity of the pathogenic isolates. To test genetic variability, isolates were analyzed using microsatellite markers. An UPGMA dendrogram for genetic variation among the isolates showed that all the isolates fell into two major clusters. The first cluster consisted of isolate Cf-10 and the second cluster was further divided into two sub-clusters. Sub-cluster one consisted of isolate Cf-2. Sub-cluster two was again divided into five groups. The first group included isolate Cf-13, the second group consisted of isolate Cf-14, the third group included isolates Cf-1, Cf-4, Cf-6, Cf-7, Cf-8 and Cf-9, the fourth group included Cf-5 and Cf-11, and the fifth group consisted of Cf-3, Cf-12 and Cf-15. The dissimilarity coefficient ranged from 0.00 to 0.20 among the isolates. Isolates Cf-1, Cf-3, Cf-4, Cf-5 Cf-6, Cf-7, Cf-8, Cf-9, Cf-11, Cf-12 and Cf-15 were found to be highly similar, as their dissimilarity coefficient was zero. Maximum dissimilarity (0.20) was found between isolate Cf-10 and all the other isolates, suggesting they were genetically distinct.

Co-occurrence of true truffle mycelia in Tuber magnatum fruiting sites

Tuber magnatum (the white truffle) is the most precious species of the genus Tuber which comprises the hypogeous ectomycorrhizal species called "true truffle." Despite its high economic value, the knowledge on its ecology is scant, principally due to the difficulty to find its mycorrhizas in the soil. The possibility to detect its mycelium by DNA extracted from soil has given a new chance for studying this truffle species. In this work, the co-occurrence of other Tuber species with T. magnatum mycelium was investigated by using species-specific primers in several productive areas located in central and northern Italy. Most (82%) of the examined soil samples showed at least one other Tuber species in addition to T. magnatum. The most common was T. maculatum (72% of soil samples) followed by T. borchii, T. rufum, T. brumale, T. dryophilum, T. macrosporum, and T. melanosporum (40%, 37%, 22%, 19%, 12%, and 1% of soil samples, respectively). Tuber aestivum was never detected in T. magnatum productive patches. Analysis of species co-occurrence showed that the pairwise associations between T. dryophilum-T. brumale, T. brumale-T. borchii, and T. borchii-T. dryophilum was significant. The results suggest that Tuber mycelial network in white truffle grounds is much more extensive than the distribution of their ectomycorrhizas and competitive exclusion between different Tuber species seems to take place only for root colonization.

High-Throughput DNA Sequence-Based Analysis of AMF Communities

Arbuscular mycorrhizal fungi (AMF) are obligate symbionts of most land plants. They have great ecological and economic impacts as they support plant nutrition and water supply, soil structure, and plant resistance to pathogens. Investigating AMF presence and distribution at small and large scales is critical. Therefore, research requires standard protocols to be easily implemented. In this chapter, we describe a workflow for AMF identification by high-throughput sequencing through Illumina MiSeq platform of two DNA target regions: small subunit (SSU) and internal transcribed spacer (ITS). The protocol can apply to both soil and root AMF communities.

Confirming infection of hop plants inoculated with Verticilium nonalfalfae

Hop (Humulus lupulus L.) is grown mostly as flavouring and bittering ingredient for beer and is also appreciated in the herbal and cosmetic industry, as well as in pharmacology. Among several diseases that damage hop growing, the most devastating in European hop production is verticillium wilt, caused by the soil-borne fungal pathogen Verticillium nonalfalfae. Colonization pattern and differential expression of selected genes after artificial infection of susceptible and resistant hop cultivars with V. nonalfalafae in stems and roots have been analysed recently Švara et al., 2019. Here, we present the dataset related to verification of plant samples infections after artificial inoculation (fungi- and mock-inoculated). After inoculation plant samples were tested for the positive infection by PCR amplification of the V. nonalfalfae ITS DNA region with species specific primers developed and optimised for this purpose. For more insight please see the article "Temporal and spatial assessment of defence responses in resistant and susceptible hop cultivars during infection with Verticillium nonalfalfae".