Cultivar-specific dynamics: unravelling rhizosphere microbiome responses to water deficit stress in potato cultivars.

BACKGROUND: Growing evidence suggests that soil microbes can improve plant fitness under drought. However, in potato, the world's most important non-cereal crop, the role of the rhizosphere microbiome under drought has been poorly studied. Using a cultivation independent metabarcoding approach, we examined the rhizosphere microbiome of two potato cultivars with different drought tolerance as a function of water regime (continuous versus reduced watering) and manipulation of soil microbial diversity (i.e., natural (NSM), vs. disturbed (DSM) soil microbiome). RESULTS: Water regime and soil pre-treatment showed a significant interaction with bacterial community composition of the sensitive (HERBST) but not the resistant cultivar (MONI). Overall, MONI had a moderate response to the treatments and its rhizosphere selected Rhizobiales under reduced watering in NSM soil, whereas Bradyrhizobium, Ammoniphilus, Symbiobacterium and unclassified Hydrogenedensaceae in DSM soil. In contrast, HERBST response to the treatments was more pronounced. Notably, in NSM soil treated with reduced watering, the root endophytic fungus Falciphora and many Actinobacteriota members (Streptomyces, Glycomyces, Marmoricola, Aeromicrobium, Mycobacterium and others) were largely represented. However, DSM soil treatment resulted in no fungal taxa and fewer enrichment of these Actinobacteriota under reduced watering. Moreover, the number of bacterial core amplicon sequence variants (core ASVs) was more consistent in MONI regardless of soil pre-treatment and water regimes as opposed to HERBST, in which a marked reduction of core ASVs was observed in DSM soil. CONCLUSIONS: Besides the influence of soil conditions, our results indicate a strong cultivar-dependent relationship between the rhizosphere microbiome of potato cultivars and their capacity to respond to perturbations such as reduced soil moisture. Our study highlights the importance of integrating soil conditions and plant genetic variability as key factors in future breeding programs aiming to develop drought resistance in a major food crop like potato. Elucidating the molecular mechanisms how plants recruit microbes from soil which help to mitigate plant stress and to identify key microbial taxa, which harbour the respective traits might therefore be an important topic for future research.

Effect of Spirulina (Arthrospira platensis) Supplementation on Physical and Chemical Properties of Semolina (Triticum durum) Based Fresh Pasta.

Taking into account that many advantages have been associated with the consumption of spirulina (microalgae) in terms of antioxidant capacity, anticancer, anti-inflammatory, and anti-aging activities, the study focuses on spirulina supplementation of semolina-based pasta. Fresh pasta was prepared by mixing semolina flour (Triticum durum) with an addition of 3, 5, 7, and 10% (w/w) of spirulina (Arthrospira platensis) powder. Physicochemical and nutritional analyses were done on raw materials, and on fresh pasta before and after cooking. Sensorial analysis was done shortly after cooking pastas. Spirulina had a high content of protein (71.34%), with all the essential amino acids, a high total fiber (8.45%), as well as ash content (5.93%), which significantly increased the nutritional value of the obtained fresh pasta. Supplemented pastas have a significantly better amino acid profile and higher total fiber content (up to 2.99 g/100 g d.m.) than the control sample. Moreover, the addition of spirulina had a significant effect on the pasta's color, weight gain, and cooking loss after being cooked. The addition of spirulina also affected the scores obtained for the individual parameters (texture, color, flavor, taste, and overall acceptability) of the sensory evaluation.

Antidiabetic and Antioxidative Potential of the Blue Congo Variety of Purple Potato Extract in Streptozotocin-Induced Diabetic Rats.

This study was designed to evaluate the effects of purple potato extract of the Blue Congo variety (PP) on diabetes and its antioxidant activities after two-week administration tostreptozotocin (STZ)-induced diabetic rats. The activities of PP were evaluated at a dose of 165 mg/kg body weight (b.w.) by estimating biochemical changes in blood plasma and through a histopathological study of kidney, muscles, and liver tissue. We evaluated the effect of treatment with extract on glucose level, glycated hemoglobin, activities of enzymatic antioxidants (including superoxide dismutase, glutathione peroxidase, and catalase), and lipid peroxidation. Moreover, we determined advanced glycation end-products (AGEs), advanced oxidation protein products (AOPPs), and the level of oxidative modified proteins (OMPs) as markers of carbonyl-oxidative stress in rats with diabetes. Using high-performance liquid chromatography, we identified five anthocyanins and six phenolic acids in the extract from Blue Congo with the dominant acylated anthocyanin as petunidin-3-p-coumaroyl-rutinoside-5-glucoside. The administration of Blue Congo extract lowered blood glucose, improved glucose tolerance, and decreased the amount of glycated hemoglobin. Furthermore, PP demonstrated an antioxidative effect, suppressed malondialdehyde levels, and restored antioxidant enzyme activities in diabetic rats. After administration of PP, we also noticed inhibition of OMP, AGE, and AOPP formation in the rats' blood plasma.