Background Globodera rostochiensis belongs to major potato pathogens with a sophisticated mechanism of interaction with roots of the host plants. Resistance of commercial varieties is commonly based on specific R genes introgressed from natural populations of related wild species and from native potato varieties grown in the Andean highlands. Investigation of molecular resistance mechanisms and screening the natural populations for novel R genes are important for both fundamental knowledge on plant pathogen interactions and breeding for durable resistance. Here we exploited the Solanum phureja accessions collected in South America with contrasting resistance to G. rostochiensis. Results The infestation of S. phureja with G. rostochiensis juveniles resulted in wounding stress followed by activation of cell division and tissue regeneration processes. Unlike the susceptible S. phureja genotype, the resistant accession reacted by rapid induction of variety of stress response related genes. This chain of molecular events accompanies the hypersensitive response at the juveniles’ invasion sites and provides high-level resistance. Transcriptomic analysis also revealed considerable differences between the analyzed S. phureja genotypes and the reference genome. Conclusion The molecular processes in plant roots associated with changes in gene expression patterns in response to G. rostochiensis infestation and establishment of either resistant or susceptible phenotypes are discussed. De novo transcriptome assembling is considered as an important tool for discovery of novel resistance traits in S. phureja accessions.

Wild potato germplasm serves as a natural pool of agronomically valuable traits for potato breeding, such as resistance to pathogens and abiotic stresses, quality, and consumer-oriented traits. The introgression of these traits into cultivated potato is hampered by the different kinds of incompatibility and linkages between desirable and undesirable features in hybrid progeny. The trait donor improvement via correction of negative characteristics prior to hybridization to domestic potato can be a solution to the linkage drag problem. The de novo domestication concept for developing new crops using gene editing technologies was previously proposed and performed for tomato and physalis. In this review, we collected information about donor properties of different wild potato species and developed a strategy for potato germplasm enhancement using the de novo domestication approach. The possible modifications of several candidate genes responsible for undesirable traits in wild potato, including high steroidal glycoalkaloid content, self-incompatibility, tuberization under short day conditions, and long stolons are proposed. The current challenges and future prospects of implementing the de novo domestication strategy for potato are discussed.

The development of quantitative digital phenotyping methods for evaluation of wild potato (section Petota Dumort., genus Solanum L.) tuberization is required for annotation of genebank collections and selection of the suitable donor material for potato breeding. There are no available methods specifically designed for the quantitative analysis of wild potato tuber morphology. The current study is devoted to evaluation of wild potato tubers’ morphological characteristics using a digital image processing technique. For this purpose, the mobile application SeedSounter developed previously for grain analysis was specifically adapted for tuber phenotyping. The application estimates the number and shape of objects scattered on a standard sheet of white paper (i. e. A3 or A4). Twelve accessions from the VIR genebank collection belonging to nine Petota species were grown in pots protected with garden fabric during the growing season of cultivated potato (Novosibirsk region). Tubers were collected form plants of nine genotypes. Three genotypes did not produce tubers. The weight of tubers collected from each plant was measured. The tuber yield from each plant was analyzed using SeedCounter (http://wheatdb.org/seedcounter). The number of tubers per plant was counted; the following characteristics were extracted from the images of individual tubers: length, width, projected area, length to width ratio, сircularity, roundness, rugosity and solidity. One-way ANOVA showed a significant effect of genotype on all measured characteristics. A pairwise comparison of nine Petota accessions using all measured parameters revealed statistically significant differences between 86 % of pairs. The overall tuber yield volume for each plant was  calculated as a sum of volumes of individual tubers; tuber volume was calculated from its length to width ratio and projected area. A strong correlation between the evaluated tuber yield volume and yield weight was shown. We propose tuber yield volume as a characteristic for a general evaluation of tuberization for wild potato, implementing the four-step scale from 0 to 3. According to this characteristic, the twelve wild potato accessions studied could be divided into four groups with different tuberization abilities. The evaluated tuberization ability is partially in accordance with previously obtained VIR data. The results presented demonstrate the possibility to use SeedCounter for  wild potato  collections phenotyping.

О методике создания инфекционного фона фузариоза гороха овощного РЕЗЮМЕАктуальность и методика. Исследования проведены в 2018-2019 годах в Московской области во ВНИИО -филиал ФГБНУ ФНЦО на культуре гороха овощного Pisum sativum L. В результате оценки фитосанитарного состояния коллекции сортов гороха выявлено, что доминирующими патогенами и семян, и обследуемых в полевых условиях частей вегетирующих растений были грибы родов Alternaria и Fusarium с распространенностью выделяемых in vitro колоний 45-65%. С помощью метода выделения грибных патогенов с поверхности семян и проростков были получены в чистой культуре четыре изолята грибов рода Fusarium. Методом выделения популяции патогенов с органов вегетирующих растений было выделено еще пять изолятов фузариевых грибов, вызывающих корневые гнили и увядание растений в фазу формирования бобов.Результаты. По культурально-морфологическим признакам четыре изолята фузариума были идентифицированы как принадлежащие к виду F. oxysporum. С использованием метода определения агрессивности выделенных изолятов на песчаном субстрате в вегетационных емкостях был выявлен наиболее агрессивный изолят № 3, который будет использован в дальнейшей работе по созданию искусственного инфекционного фона для отбора устойчивых к фузариозу селекционных форм гороха. Авторами составлена актуальная для нового времени карта распространённости и зон вредоносности в России фузариоза гороха, вызывающего корневые гнили и трахеомикозное увядание.About the method of creating an infectious background of fusarium for vegetable pea ABSTRACT Relevance and methodology. Research was carried out in 2018-2019 in the Moscow region at VNIIO-branch of the Federal state budgetary INSTITUTION FNTSO on the culture of vegetable peas Pisum sativum L. As a result of the assessment of the phytosanitary condition of the collection of pea varieties, it was revealed that the dominant pathogens of both seeds and parts of vegetating plants examined in the field were fungi of the genera Alternaria and Fusarium with a prevalence of 45-65% of colonies isolated in vitro. Using the method of isolation of fungal pathogens from the surface of seeds and seedlings, four isolates of fungi of the genus Fusarium were obtained in pure culture. Five more isolates of Fusarium fungi that cause root rot and withering of plants during the bean formation phase were isolated using the method of isolating a population of pathogens from the organs of vegetating plants. Results.According to cultural and morphological features, four Fusarium isolates were identified as belonging to the species F. oxysporum. Using the method of determining the aggressiveness of isolated isolates on a sandy substrate in vegetation tanks, the most aggressive isolate No. 3 was identified, which will be used in further work on creating an artificial infectious background for the selection of Fusarium-resistant breeding forms of peas. The authors have compiled an up-to-date map of the prevalence and zones of harmfulness in Russia of pea fusariosis, which causes root rot and t...