SNP Diversity and Genetic Structure of "Rogosija", an Old Western Balkan Durum Wheat Collection.

Durum wheat landraces represent a genetic resource for the identification and isolation of new valuable genes and alleles, useful to increase the crop adaptability to climate change. Several durum wheat landraces, all denominated "Rogosija", were extensively cultivated in the Western Balkan Peninsula until the first half of the 20th century. Within the conservation program of the Montenegro Plant Gene Bank, these landraces were collected, but without being characterized. The main goal of this study was to estimate the genetic diversity of the "Rogosija collection" consisting of 89 durum accessions, using 17 morphological descriptors and the 25K Illumina single nucleotide polymorphism (SNP) array. The genetic structure analysis of the Rogosija collection showed two distinguished clusters localized in two different Montenegro eco-geographic micro-areas, characterized by continental Mediterranean climate and maritime Mediterranean climate. Data suggest that these clusters could be composed of two different Balkan durum landrace collections evolved in two different eco-geographic micro-areas. Moreover, the origin of Balkan durum landraces is discussed.

"Ectomosphere": Insects and Microorganism Interactions.

This study focuses on interacting with insects and their ectosymbiont (lato sensu) microorganisms for environmentally safe plant production and protection. Some cases help compare ectosymbiont microorganisms that are insect-borne, -driven, or -spread relevant to endosymbionts' behaviour. Ectosymbiotic bacteria can interact with insects by allowing them to improve the value of their pabula. In addition, some bacteria are essential for creating ecological niches that can host the development of pests. Insect-borne plant pathogens include bacteria, viruses, and fungi. These pathogens interact with their vectors to enhance reciprocal fitness. Knowing vector-phoront interaction could considerably increase chances for outbreak management, notably when sustained by quarantine vector ectosymbiont pathogens, such as the actual Xylella fastidiosa Mediterranean invasion episode. Insect pathogenic viruses have a close evolutionary relationship with their hosts, also being highly specific and obligate parasites. Sixteen virus families have been reported to infect insects and may be involved in the biological control of specific pests, including some economic weevils. Insects and fungi are among the most widespread organisms in nature and interact with each other, establishing symbiotic relationships ranging from mutualism to antagonism. The associations can influence the extent to which interacting organisms can exert their effects on plants and the proper management practices. Sustainable pest management also relies on entomopathogenic fungi; research on these species starts from their isolation from insect carcasses, followed by identification using conventional light or electron microscopy techniques. Thanks to the development of omics sciences, it is possible to identify entomopathogenic fungi with evolutionary histories that are less-shared with the target insect and can be proposed as pest antagonists. Many interesting omics can help detect the presence of entomopathogens in different natural matrices, such as soil or plants. The same techniques will help localize ectosymbionts, localization of recesses, or specialized morphological adaptation, greatly supporting the robust interpretation of the symbiont role. The manipulation and modulation of ectosymbionts could be a more promising way to counteract pests and borne pathogens, mitigating the impact of formulates and reducing food insecurity due to the lesser impact of direct damage and diseases. The promise has a preventive intent for more manageable and broader implications for pests, comparing what we can obtain using simpler, less-specific techniques and a less comprehensive approach to Integrated Pest Management (IPM).

Exploring Anastomosis of Hyphae and Mating-Type Compatibility of Pochonia chlamydosporia Isolates of the Meloidogyne, Heterodera and Globodera Biotypes.

The endophytic and nematophagous fungus Pochonia chlamydosporia is an efficient biological control agent of plant-parasitic nematodes. Isolates of the fungus can be allocated to a biotype group according to the nematode host, but it is unknown if genetic interchange can occur between different biotypes, which may affect their parasitic performance. An anastomosis assay was conducted in vitro to assess hyphae vegetative compatibility/incompatibility followed by a PCR-based mating-type assay genotyping of five isolates of P. chlamydosporia var. chlamydoporia of the Meloidogyne sp. (Pc10, Pc190, Pc309), Globodera sp. (Pc280) and Heterodera avenae (Pc60) biotypes, including 16 pairwise isolates combinations in four replicates. Pairwise combinations were tested on glass slides and mycelia were stained to confirm nuclei migration between anastomosing hyphae using fluorescence microscopy. Anastomosis only occurred between mycelium hyphae of the same isolate and biotype. Mating-type PCR-based molecular assays showed that all isolates were heterothallic. The MAT1-1 genotype was found in isolates Pc10, Pc190, Pc280, Pc309, and the MAT1-2 genotype in Pc60. The results showed a vegetative incompatibility among isolates, suggesting the occurrence of such interactions for their respective biotypes. Anastomosis and PCR mating-type results suggest that different fungal biotypes can occur in the same niche but that genetic incompatibility mechanisms, such as mating-type, may limit or impede viable heterokaryosis.

Serendipitous In Situ Conservation of Faba Bean Landraces in Tunisia: A Case Study.

Cultivation of faba bean (Vicia faba L.) in Tunisia is largely based on improved varieties of the crop. However, a few farmers continue to produce local cultivars or landraces. The National Gene Bank of Tunisia (NGBT) recently launched a collection project for faba bean landraces, with special focus on the regions of the North West, traditionally devoted to cultivating grain legumes, and where around 80% of the total national faba bean cultivation area is located. The seed phenotypic features of the collected samples were studied, and the genetic diversity and population structure analyzed using simple sequence repeat markers. The genetic constitution of the present samples was compared to that of faba bean samples collected by teams of the International Center for Agricultural Research in the Dry Areas (ICARDA) in the 1970s in the same region, and stored at the ICARDA gene bank. The results of the diversity analysis demonstrate that the recently collected samples and those stored at ICARDA largely overlap, thus demonstrating that over the past 50 years, little genetic change has occurred to the local faba bean populations examined. These findings suggest that farmers serendipitously applied international best practices for in situ conservation of agricultural crops.

Characterization of the interactions between Cucumber mosaic virus and Potato virus Y in mixed infections in tomato.

Mixed infection with the SON41 strain of Potato virus Y (PVY-SON41) in tomato increased accumulation of RNAs of strains Fny and LS of Cucumber mosaic virus (CMV-Fny and CMV-LS, respectively) and enhanced disease symptoms. By contrast, replication of PVY-SON41 was downregulated by CMV-Fny and this was due to the CMV-Fny 2b protein. The CMV-FnyΔ2b mutant was unable to systemically invade the tomato plant because its movement was blocked at the bundle sheath of the phloem. The function needed for invading the phloem was complemented by PVY-SON41 in plants grown at 22°C whereas this complementation was not necessary in plants grown at 15°C. Mutations in the 2b protein coding sequence of CMV-Fny as well as inhibition of translation of the 2a/2b overlapping region of the 2a protein lessened both the accumulation of viral RNAs and the severity of symptoms. Both of these functions were complemented by PVY-SON41. Infection of CMV-Fny supporting replication of the Tfn-satellite RNA reduced the accumulation of CMV RNA and suppressed symptom expression also in plants mixed-infected with PVY-SON41. The interaction between CMV and PVY-SON41 in tomato exhibited different features from that documented in other hosts. The results of this work are relevant from an ecological and epidemiological perspective due to the frequency of natural mixed infection of CMV and PVY in tomato.