Fitness difference between two synonymous mutations of Phytophthora infestans ATP6 gene

Background Sequence variation produced by mutation provides the ultimate source of natural selection for species adaptation. Unlike nonsynonymous mutation, synonymous mutations are generally considered to be selectively neutral but accumulating evidence suggests they also contribute to species adaptation by regulating the flow of genetic information and the development of functional traits. In this study, we analysed sequence characteristics of ATP6, a housekeeping gene from 139 Phytophthora infestans isolates, and compared the fitness components including metabolic rate, temperature sensitivity, aggressiveness, and fungicide tolerance among synonymous mutations. Results We found that the housekeeping gene exhibited low genetic variation and was represented by two major synonymous mutants at similar frequency (0.496 and 0.468, respectively). The two synonymous mutants were generated by a single nucleotide substitution but differed significantly in fitness as well as temperature-mediated spatial distribution and expression. The synonymous mutant ending in AT was more common in cold regions and was more expressed at lower experimental temperature than the synonymous mutant ending in GC and vice versa. Conclusion Our results are consistent with the argument that synonymous mutations can modulate the adaptive evolution of species including pathogens and have important implications for sustainable disease management, especially under climate change

Evaluating the contribution of historical and contemporary temperature to the oospore production of self-fertile Phytophthora infestans

Reproductive systems play an important role in the ecological function of species, but little is known about how climate change, such as global warming, may affect the reproductive systems of microbes. In this study, 116 Phytophthora infestans isolates sampled from five different altitudes along a mountain were evaluated under five temperature regimes to determine the effects of historical and experimental temperature on the reproductive system of the pathogen. Both altitude, a proxy for historical pathogen adaptation to temperature, and temperature used in the experiment affected the sexual reproduction of the pathogen, with experimental temperature, that is, contemporary temperature, playing a role several times more important than historical temperature. Furthermore, the potential of sexual reproduction, measured by the number of oospores quantified, increased with the temperature breadth (i.e., difference between the highest and lowest temperature at which sexual reproduction takes place) of the pathogen and reached the maximum at the experimental temperature of 21(degrees)C, which is higher than the annual average temperature in many potato-producing areas. The results suggest that rising air temperature associated with global warming may increase the potential of sexual reproduction in P. infestans. Given the importance of sexuality in pathogenicity and ecological adaptation of pathogens, these results suggest that global warming may increase the threat of P. infestans to agricultural production and other ecological services and highlight that new epidemiological strategies may need to be implemented for future food security and ecological resilience

Inonotus obliquus polysaccharide are linear molecules that alter the abundance and composition of intestinal microbiota in Sprague Dawley rats

Introduction: The macromolecular polysaccharide Inonotus obliquus polysaccharide (IOP) is composed of various monosaccharides, and it could modulate the composition and diversity of intestinal flora. However, its impact on the intestinal flora in rats of different genders remains unclear. Therefore, this study aims to investigate the structural changes of IOP and its effects on the intestinal flora after administration in male and female rats.Methods: In this study, the molecular weight and purity of IOP were analyzed by high-performance gel permeation chromatography (HPGPC) and phenol sulfuric acid method, and NMR was used to confirm the chemical structure of IOP. Sex hormone [testosterone (T) and estradiol (E2)] levels and intestinal microbial changes were detected by enzyme-linked immunosorbent assay (ELISA) and 16S rRNA, respectively, after gavage of IOP (100 mg/kg) in male and female Sprague Dawley (SD) rats.Results: HPGPC analysis showed that the average molecular weight (Mw) of IOP was 4,828 Da, and the total sugar content of the purified IOP was 96.2%, indicating that the polysaccharide is of high purity. NMR revealed that IOP is a linear macromolecule with an alpha-D-type glucose backbone. The results of ELISA and 16S rRNA showed that the IOP increased the abundance of beneficial bacteria, such as Clostridia_UCG-014 and Prevotellaceae_NK3B31, and reduced that of harmful bacteria, such as Colidextribacter and Desulfobacterota in the intestine of both male and female rats, and IOP changed the levels of sex hormones in male and female rats. Further analyses revealed that the increase in alpha diversity was higher in male than female rats. alpha diversity and beta diversity revealed a significant difference in the composition of cecal microbiota between male and female rats in the control group, but IOP intake reduced this difference. Meanwhile, alpha analysis revealed a change in the composition of bacterial flora was more stable in male than female rats.Conclusions: This study enhances our comprehension of the IOP structure and elucidates the alterations in intestinal flora following IOP administration in rats of varying genders. Nonetheless, further investigation is warranted to explore the specific underlying reasons for these discrepancies

Modeling plant diseases under climate change: evolutionary perspectives

Infectious plant diseases are a major threat to global agricultural productivity, economic development, and ecological integrity. There is widespread concern that these social and natural disasters caused by infectious plant diseases may escalate with climate change and computer modeling offers a unique opportu-nity to address this concern. Here, we analyze the intrinsic problems associated with current modeling strategies and highlight the need to integrate evolutionary principles into polytrophic, eco-evolutionary frameworks to improve predictions. We particularly discuss how evolutionary shifts in functional trade-offs, relative adaptability between plants and pathogens, ecosystems, and climate preferences induced by climate change may feedback to future plant disease epidemics and how technological advances can facilitate the generation and integration of this relevant knowledge for better modeling predictions

Modelling potato yield losses caused by Phytophthora infestans: Aspects of disease growth rate, infection time and temperature under climate change

Modelling crop yield loss due to pathogens remains a challenge due to the complex and dynamic interactions involved. Here, we develop a parsimonious dynamic yield loss simulation model that couples a simple epidemiological model of late blight disease with a basic model of potato crop growth. The model is parameterized using 17 years of field data on disease progress of potato late blight and potato yield in southern Sweden. Simulated actual yields (yields obtained under the presence of Phytopthora infestans) correlated well (R2 = 0.66) with the actual yields observed in field trials, using a few widely accessible meteorological variables. The results also underline the impact of disease growth rate and the time of infection on yield losses, with relatively low rates and early onset of the epidemic producing large yield reductions. In addition, the importance of increasing temperature due to climate change on both potato crop and Phytophthora infestans development was simulated, suggesting that higher temperatures may be more detrimental for the pathogen than for the crop. Additional ways to expand the model are discussed, and the inclusion of other diseases and pests are encouraged, indicating the potential to improve disease management in potato production

Disease influences host population growth rates in a natural wild plant-pathogen association over a 30-year period

1. The epidemiological and demographic dynamics of plant-pathogen interactions in natural environments are strongly affected by spatial and temporal influences. Here we assess the interaction between Filipendula ulmaria and its rust pathogen Triphragmium ulmariae by analysing a 30-year long dataset that has followed pathogen and plant population dynamics in a metapopulation of similar to 230 host patches growing on islands of the Skeppsvik archipelago in northern Sweden.2. Over this period, the host metapopulation initially expanded in both number and size of individual patches before plateauing. In contrast, the pathogen metapopulation showed greater change. Disease incidence showed a convex pattern rising for the first decade before showing a marked decline in the last decade. At the same time, the prevalence of disease in infected populations showed a constant 30-year long decline.3. At the individual host population level, each population was annually classified into one of four inter-year states: healthy, recolonization, extinction and diseased. Host populations that were healthy from 1 year to the next were significantly smaller than all other host population categories, while host populations in which disease was constantly present were significantly larger.4. Host populations in which the pathogen underwent either an extinction or a recolonization event were of similar size and represented a measure of the host threshold size for long-term pathogen survival.5. Host population growth rates declined as disease levels increased. The growth rate of host populations in which disease was continuously present was 75% lower than in populations that were free disease.6. The sensitivity of the association to climate change as demonstrated through a decline in disease incidence and prevalence and an increase in drought damage to plant populations as temperatures rise has only become apparent through analysis of an extensive long-term dataset.7. Synthesis. To date wild plant-pathogen studies have focused on the epidemiology of the pathogen and its effect on individual plant fitness. Here we have established a link to the impact of the pathogen on the long-term dynamics of host populations. This has the potential to trigger a cascade of changes in the species composition and diversity of communities

Target of Rapamycin Regulates Photosynthesis and Cell Growth in Auxenochlorella pyrenoidosa

Auxenochlorella pyrenoidosa is an efficient photosynthetic microalga with autotrophic growth and reproduction, which has the advantages of rich nutrition and high protein content. Target of rapamycin (TOR) is a conserved protein kinase in eukaryotes both structurally and functionally, but little is known about the TOR signalling in Auxenochlorella pyrenoidosa. Here, we found a conserved ApTOR protein in Auxenochlorella pyrenoidosa, and the key components of TOR complex 1 (TORC1) were present, while the components RICTOR and SIN1 of the TORC2 were absent in Auxenochlorella pyrenoidosa. Drug sensitivity experiments showed that AZD8055 could effectively inhibit the growth of Auxenochlorella pyrenoidosa, whereas rapamycin, Torin1 and KU0063794 had no obvious effect on the growth of Auxenochlorella pyrenoidosa a. Transcriptome data results indicated that Auxenochlorella pyrenoidosa TOR (ApTOR) regulates various intracellular metabolism and signaling pathways in Auxenochlorella pyrenoidosa. Most genes related to chloroplast development and photosynthesis were significantly down-regulated under ApTOR inhibition by AZD8055. In addition, ApTOR was involved in regulating protein synthesis and catabolism by multiple metabolic pathways in Auxenochlorella pyrenoidosa. Importantly, the inhibition of ApTOR by AZD8055 disrupted the normal carbon and nitrogen metabolism, protein and fatty acid metabolism, and TCA cycle of Auxenochlorella pyrenoidosa cells, thus inhibiting the growth of Auxenochlorella pyrenoidosa. These RNA-seq results indicated that ApTOR plays important roles in photosynthesis, intracellular metabolism and cell growth, and provided some insights into the function of ApTOR in Auxenochlorella pyrenoidosa

Triple bottom-line consideration of sustainable plant disease management: From economic, sociological and ecological perspectives

Plant disease management plays an important role in achieving the sustainable development goals of the United Nations (UN) such as food security, human health, socio-economic improvement, resource conservation and ecological resilience. However, technologies available are often limited due to different interests between producers and society and lacks of proper understanding of economic thresholds and the complex interactions among ecology, productivity and profitability. A comprehensive synergy and conflict evaluation of economic, sociological and ecological effects with technologies, productions and evolutionary principles as main components should be used to guide sustainable disease management that aims to mitigate crop and economic losses in the short term while maintaining functional farm ecosystem in the long term. Consequently, there should be an increased emphasis on technology development, public education and information exchange among governments, researchers, producers and consumers to broaden the options for disease management in the future

Single Amino Acid Substitution the DNA Repairing Gene Radiation-Sensitive 4 Contributes to Ultraviolet Tolerance of a Plant Pathogen

To successfully survive and reproduce, all species constantly modify the structure and expression of their genomes to cope with changing environmental conditions including ultraviolet (UV) radiation. Thus, knowledge of species adaptation to environmental changes is a central theme of evolutionary studies which could have important implication for disease management and social-ecological sustainability in the future but is generally insufficient. Here, we investigated the evolution of UV adaptation in organisms by population genetic analysis of sequence structure, physiochemistry, transcription, and fitness variation in the radiation-sensitive 4 (RAD4) gene of the Irish potato famine pathogen Phytophthora infestans sampled from various altitudes. We found that RAD4 is a key gene determining the resistance of the pathogen to UV stress as indicated by strong phenotype-genotype-geography associations and upregulated transcription after UV exposure. We also found conserved evolution in the RAD4 gene. Only five nucleotide haplotypes corresponding to three protein isoforms generated by point mutations were detected in the 140 sequences analyzed and the mutations were constrained to the N-terminal domain of the protein. Physiochemical changes associated with non-synonymous mutations generate severe fitness penalty to mutants, which are purged out by natural selection, leading to the conserved evolution observed in the gene