The Rysto immune receptor recognises a broadly conserved feature of potyviral coat proteins.

Knowledge of the immune mechanisms responsible for viral recognition is critical for understanding durable disease resistance and successful crop protection. We determined how potato virus Y (PVY) coat protein (CP) is recognised by Rysto , a TNL immune receptor. We applied structural modelling, site-directed mutagenesis, transient overexpression, co-immunoprecipitation, infection assays and physiological cell death marker measurements to investigate the mechanism of Rysto -CP interaction. Rysto associates directly with PVY CP in planta that is conditioned by the presence of a CP central 149 amino acids domain. Each deletion that affects the CP core region impairs the ability of Rysto to trigger defence. Point mutations in the amino acid residues Ser125 , Arg157 , and Asp201 of the conserved RNA-binding pocket of potyviral CP reduce or abolish Rysto binding and Rysto -dependent responses, demonstrating that appropriate folding of the CP core is crucial for Rysto -mediated recognition. Rysto recognises the CPs of at least 10 crop-damaging viruses that share a similar core region. It confers immunity to plum pox virus and turnip mosaic virus in both Solanaceae and Brassicaceae systems, demonstrating potential utility in engineering virus resistance in various crops. Our findings shed new light on how R proteins detect different viruses by sensing conserved structural patterns.

Extreme resistance to Potato virus Y in potato carrying the Rysto gene is mediated by a TIR-NLR immune receptor.

Potato virus Y (PVY) is a major potato (Solanum tuberosum L.) pathogen that causes severe annual crop losses worth billions of dollars worldwide. PVY is transmitted by aphids, and successful control of virus transmission requires the extensive use of environmentally damaging insecticides to reduce vector populations. Rysto , from the wild relative S. stoloniferum, confers extreme resistance (ER) to PVY and related viruses and is a valuable trait that is widely employed in potato resistance breeding programmes. Rysto was previously mapped to a region of potato chromosome XII, but the specific gene has not been identified to date. In this study, we isolated Rysto using resistance gene enrichment sequencing (RenSeq) and PacBio SMRT (Pacific Biosciences single-molecule real-time sequencing). Rysto was found to encode a nucleotide-binding leucine-rich repeat (NLR) protein with an N-terminal TIR domain and was sufficient for PVY perception and ER in transgenic potato plants. Rysto -dependent extreme resistance was temperature-independent and requires EDS1 and NRG1 proteins. Rysto may prove valuable for creating PVY-resistant cultivars of potato and other Solanaceae crops.

MIX2: A Novel Natural Multi-Component Modulator of Multidrug-Resistance and Hallmarks of Cancer Cells.

Multidrug resistance is one of the key barriers suppressing the effectiveness of drug therapies of malignant tumors. Here, we report a study on the effect of a mix of natural extracts (MIX2) prepared from fresh fruits of Prunus spinosa, Crataegus monogyna, Sorbus aucuparia, and Euonymus europaeus on the classic hallmarks of cancer cells and the expression of multidrug resistance proteins. In the studies, HeLa and T98G cell lines, and classic methods of molecular biology, including RT-qPCR, Western blot, flow cytometry, and confocal imaging, were used. Additionally, migration, adhesion, and proliferation assays were performed. The obtained results indicate that the MIX2 cocktail presents strong anti-cancer properties. MIX2 is not toxic, but at the same time significantly alters the migration, proliferation, and adhesion of tumor cells. Furthermore, it was found that cells exposed to the mixture presented a significantly reduced expression level of genes associated with MDR, including ABCB1, which encodes for glycoprotein P. In vitro data showed that MIX2 effectively sensitizes tumor cells to doxorubicin. We postulate that modulation of the multidrug resistance phenotype of tumors with the use of MIX2 may be considered as a safe and applicable tool in sustaining drug delivery therapies of malignancies.

Two Strategies of Pseudomonas syringae to Avoid Recognition of the HopQ1 Effector in Nicotiana Species.

Pseudomonas syringae employs a battery of type three secretion effectors to subvert plant immune responses. In turn, plants have developed receptors that recognize some of the bacterial effectors. Two strain-specific HopQ1 effector variants (for Hrp outer protein Q) from the pathovars phaseolicola 1448A (Pph) and tomato DC3000 (Pto) showed considerable differences in their ability to evoke disease symptoms in Nicotiana benthamiana. Surprisingly, the variants differ by only six amino acids located mostly in the N-terminal disordered region of HopQ1. We found that the presence of serine 87 and leucine 91 renders PtoHopQ1 susceptible to N-terminal processing by plant proteases. Substitutions at these two positions did not strongly affect PtoHopQ1 virulence properties in a susceptible host but they reduced bacterial growth and accelerated onset of cell death in a resistant host, suggesting that N-terminal mutations rendered PtoHopQ1 susceptible to processing in planta and, thus, represent a mechanism of recognition avoidance. Furthermore, we found that co-expression of HopR1, another effector encoded within the same gene cluster masks HopQ1 recognition in a strain-dependent manner. Together, these data suggest that HopQ1 is under high host-pathogen co-evolutionary selection pressure and P. syringae may have evolved differential effector processing or masking as two independent strategies to evade HopQ1 recognition, thus revealing another level of complexity in plant - microbe interactions.

Biotechnological approaches to enhance salidroside, rosin and its derivatives production in selected Rhodiola spp. in vitro cultures.

Rhodiola (Crassulaceae) an arctic-alpine plant, is extensively used in traditional folk medicine in Asian and European countries. A number of investigations have demonstrated that Rhodiola preparations exhibit adaptogenic, neuroprotective, anti-tumour, cardioprotective, and anti-depressant effects. The main compounds responsible for these activities are believed to be salidroside, rosin and its derivatives which became the target of biotechnological investigations. This review summarizes the results of the diverse biotechnological approaches undertaken to enhance the production of salidroside, rosin and its derivatives in callus, cell suspension and organ in vitro cultures of selected Rhodiola species.

Approaches of Rhodiola kirilowii and Rhodiola rosea field cultivation in Poland and their potential health benefits.

Numerous researches have been carried out on plants of the Rhodiola species, especially Rhodiola kirilowii (Regel) Maxim. and Rhodiola rosea. Various compounds have been reported to be isolated from R. kirilowii and R. rosea, including cyanogenic glycosides, monoterpene alcohols and their glycosides, aryl glycosides, phenylethanoids, phenylpropanoids and their glycosides (salidroside and rosavins respectively), as well as flavonoids, flavonlignans, proanthocyanidins and gallic acid derivatives and the latter have free radical scavenging capacity. The benefits claimed for Rhodiola include adapogenic, neuroprotective, anti-depresive anti-tumour and cardioprotective activities. Currently, the adaptogenic activity of Rhodiola compounds are properties evaluated mainly in human clinical trials. The mechanism of the action of Rhodiola extracts include affecting the levels of cortisol and NO by interactions with glucocorticoid receptors directly or via the c-Jun N-terminal protein kinase (JNK) pathway. However, the natural populations of R. rosea in Poland are threatened; therefore, the cultivation of R. rosea and alternative species R. kirilowii might be a possible solution for producing these kinds of plants in Poland in sufficient quantities and quality for pharmaceutical purposes. Lack of proven interaction with other drugs and no confirmed adverse effects during clinical trials encourages further investigation. These herb preparations ought to be studied extensively to establish their position as potential drugs for a variety of diseases.

Biotransformation of cinnamyl alcohol to rosavins by non-transformed wild type and hairy root cultures of Rhodiola kirilowii.

Non-transformed wild type (NTWT) and hairy root cultures of Rhodiola kirilowii were grown in medium supplemented with 2.5 mM cinnamyl alcohol as a precursor and/or sucrose (1 %) on the day of inoculation or on the 14th day of culture. Rosarin, rosavin, and rosin were produced by NTWT root culture but only rosarin and rosavin by hairy roots. Approximately 80 and 95 % of the glycosides were released into the medium for NTWT and hairy root cultures, respectively. The highest rosavin yield, 505 ± 106 mg/l, was in hairy root culture when cinnamyl alcohol was applied on the day of inoculation with the addition of sucrose on the 14th day of culture. For rosin production, supplementation with cinnamyl alcohol alone on day 14 was more favourable with the highest amount 74 ± 10 mg/l in NTWT root culture. Only traces of rosarin were detected.