Main conclusion: Using late blight resistance genes targeting conservative effectors of Phytophthora infestans and the constructing gene pyramids may lead to durable, broad-spectrum resistance, which could be accelerated through genetic engineering. Potato (Solanum tuberosum L.) is one of the most important food crops worldwide. In 2020, potato production was estimated to be more than 359 million tons according to the Food and Agriculture Organization (FAO). Potato is affected by many pathogens, among which Phytophthora infestans, causing late blight, is of the most economic importance. Crop protection against late blight requires intensive use of fungicides, which has an impact on the environment and humans. Therefore, new potato cultivars have been bred using resistance genes against P. infestans (Rpi genes) that originate from wild relatives of potato. Such programmes were initiated 100 years ago, but the process is complex and long. The development of genetic engineering techniques has enabled the direct transfer of resistance genes from potato wild species to cultivars and easier pyramiding of multiple Rpi genes, which potentially increases the durability and spectrum of potato resistance to rapidly evolving P. infestans strains. In this review, we summarize the current knowledge concerning Rpi genes. We also discuss the use of Rpi genes in breeding as well as their detection in existing potato cultivars. Last, we review new sources of Rpi genes and new methods used to identify them and discuss interactions between P. infestans and host.

Parthenocarpy (seedless fruits) is a desirable trait that has been achieved in many plant cultivars. We generated parthenocarpic cucumber fruits by introducing the chimeric DefH9-iaaM construct into the cucumber genome using an Agrobacterium tumefaciens-mediated protocol. The construct consists of the DefH9 promoter from Antirrhinum majus and the iaaM coding sequence from Pseudomonas syringae. Transgenic plants were obtained from nine independent transformation events: half of these were tetraploid and did not produce seeds following self-pollination, while the remaining half were capable of displaying parthenocarpy in the subsequent reproductive generation. Of the fruits produced by the transgenic lines, 70–90% were parthenocarpic. The segregation of the marker gene in the transgenic T1 progeny indicated single gene inheritance. The seed set in the transgenic lines and their F1 hybrids was lower than in the non-transgenic control plants. Some of the methodological details and the practical significance of the results are discussed.

Resistance to Potato virus Y (PVY) is one of the most important traits in seed and ware potato production. Currently the tobacco-necrosis inducing PVY^N strain including PVY^N-Wi and PVY^NTN dominates in the PVY population in Poland. The PVY^O strain which dominated in early 1980s is rarely detected. Since early 1950s, breeding for PVY resistance in IHAR was a part of the program developing parental lines, which resulted in selecting lines extremely resistant to PVY. The selection of these lines was improved by the application of developed molecular markers. Moreover, the group of genes conferring comprehensive hypersensitive resistance (HR) to all strains of PVY was identified and mapped. The cultivars obtained from parental lines have enhanced level of resistance to PVY. For registered cultivars, the level of resistance to PVY is monitored in field exposure tests, while the reaction to four different isolates of PVY is examined by artificial inoculations. The 36 cultivars with field resistance scores 7.5 and 9 expressed resistance to all tested isolates and 23 of them originated from IHAR parental lines. Several moderately resistant cultivars varied in sensitivity to the PVY isolates and in majority they were more sensitive to isolates Wi (collected in 1984) and 12/94 (collected in 1994), than to older isolates LW and Ny collected in 1970-ties. La resistencia al virus Y de la papa (PVY) es uno de los caracteres más importantes en la producción de papa para semilla y consumo. Actualmente, la variante que induce necrosis en tabaco PVY^N incluyendo PVY^N-Wi y PVY^NTN domina en la población de PVY en Polonia. Se detecta raramente la variante PVY^O que dominó a principio de los 1980s. Desde el inicio de los 1950s el mejoramiento para resistencia a PVY en IHAR era parte del programa para el desarrollo de líneas parentales, lo que resultó en la selección de líneas extremadamente resistentes al PVY. Se mejoró la selección de estas líneas mediante la aplicación de marcadores moleculares desarrollados. Más aún, se identificó y mapeó el grupo de genes que confieren reacciones de hipersensibilidad (HR) que incluyen a todas las variantes de PVY. Las variedades que se obtuvieron de las líneas parentales han incrementado su nivel de resistencia al PVY. Para variedades registradas, se monitorea el nivel de resistencia al PVY en pruebas de exposición en el campo, mientras que se examina la reacción a cuatro variantes diferentes de PVY mediante inoculaciones artificiales. Las 36 variedades con resistencia de campo alcanzan calificaciones de 7.5. Nueve expresaron resistencia a todos los aislamientos probados, y 23 de ellas se originaron de líneas parentales de IHAR. Diversas variedades moderadamente resistentes fluctuaron en sensibilidad a los aislamientos de PVY y en su mayoría fueron más sensibles a los aislamientos Wi (colectados en 1984) y 12/94 (colectados en 1994), que a aislamientos más viejos LW y Ny colectados en los 1970s.