STATE OF MICROPHYTE CENOSES AT THE WATER'S EDGE IN THE VICINITY OF THE PORT OF YERSAI AND THE VILLAGE OF KURYK (EASTERN CASPIAN SEA)

Microphytic cenoses that develop on coastal rocks in the area of the water's edge can serve as particularly bright indicator biosystems that clearly display any harmful effects on their habitat. Developing, in fact, in the water-land boundary conditions, in the area of direct impact of the surface film of continuously moving water, they are a kind of " sponges " that collect a variety of agents carried by sea currents from sources of pollution. Accumulating in these communities, such agents are able to change the balance of species in the structure of these coenoses in a short time, as well as cause morphological changes in the species themselves. These modifications of the appearance can be caused both by their phenotypic norm of reaction to the presence and high concentrations of the contaminating agent, and by mutations provoked by one or another agent. Based on the obtained results describing the state of microepiphytic and microepilitic cenoses in various locations located at the end of July 2019 in the vicinity of the port of Ersai and the village of Kuryk, it can be concluded that the communities of all three locations were under stress – however, to a significantly different degree.

Developing donors of ultra-early maturity in barley

Background. The length of the growing season is a limiting factor in many regions with unstable climatic conditions. The development of ultra-early barley donors makes it possible to accelerate the breeding process aimed at producing commercial cultivars adapted to cultivation area requirements.Materials and methods. The donors Kibel, Kibel uluchshenny, Kibtsel and Kibkor were obtained through individual selection of barley forms combining earliness and productivity from the hybrid combination Belogorsky × k-15881. The experiments were carried out according to the approved guidelines. Yield components were used to calculate the index of productivity for the donors versus the reference cv. ‘Belogorsky’.Results and conclusions. Earliness is controlled in the donors by three recessive genes. The donors’ period from emergence to heading was 7–9 days shorter than that of the reference cv. ‘Belogorsky’, with a low norm of reaction, which attested to their high adaptability. The resulting barley forms were highly resistant to lodging. The donor Kibel uluchshenny in all spike yield components did not differ from the reference. The other donors were close to the reference in spike length and 1000 seed weight. The example of Kibel uluchshenny was used to demonstrate the possibility of producing barley forms combining high earliness and good productivity. The developed donors may prove useful in the breeding for earliness in the areas where the length of the growing season is a limiting factor.

Plant height of soft winter wheat varieties and its connection with winter hardiness in the conditions of the forest-steppe of the Middle Volga region

Research has been carried out to study the height of plants of prospective soft winter wheat of different ecological and geographical origin in the forest-steppe of the Middle Volga region. It was found out that the height of the plants of the studied winter soft wheat varieties is characterized by a wide norm of reaction to changes in growing conditions. A positive correlation and regression dependence of winter hardiness on plant height was revealed. The contribution of plant height to winter hardiness of soft winter wheat is 56.7%. Individual dwarf and semi-dwarf prospective varieties of soft winter wheat with increased and high winter hardiness in specific environmental conditions were identified.

Variability of the period between germination and heading in spring barley accessions from Dagestan

Background. The genetic variability of the period between the germination and heading phases was analyzed in barley accessions from the Republic of Dagestan planted in the southern area of Dagestan (Derbent) and the Northwest of Russia (Pushkin, St. Petersburg). Testing barley development rates under contrasting climate conditions of Russia makes it possible to assess the paratypic variability and a norm of reaction in the tested accessions in order to identify environmentally adaptable plant forms useful for breeding.Materials and methods. Under spring sowing, 173 spring barley accessions were studied for the duration of the period from germination to heading. To compare the earliness of accessions planted at two sites with different sowing schedules, “the rate by which the germination-to-heading period of an accession exceeded its minimum value across the sample” was used as a criterion for calculations.Results and conclusions. Accession k-15013 was the earliest at both test sites during two years of studying. In Dagestan, accessions k-11439 and k-11475 with a low norm of reaction in 2016 and 2017 were also identified as early. Environmental conditions were found to have a significant effect on the development rate of barley accessions in Derbent and St. Petersburg. Dagestani barleys in the North-west of Russia ripened earlier than in the south of Dagestan during all the years of study. Vernalization temperatures proved to be the main factor affecting maturation schedules of local Dagestani barleys in the area of their distribution. A longer day and the absence of high temperatures in St. Petersburg contributed to the earliness of barley accessions.

Trade-offs between host tolerances to different pathogens in plant–virus interactions

Although accumulating evidence indicates that tolerance is a plant defence strategy against pathogens as widespread as resistance, how plants evolve tolerance is poorly understood. Theory predicts that hosts will evolve to maximize tolerance or resistance, but not both. Remarkably, most experimental works failed in finding this trade-off. We tested the hypothesis that the evolution of tolerance to one virus is traded-off against tolerance to others, rather than against resistance and identified the associated mechanisms. To do so, we challenged eighteen Arabidopsis thaliana genotypes with Turnip mosaic virus (TuMV) and Cucumber mosaic virus (CMV). We characterized plant life-history trait modifications associated with reduced effects of TuMV and CMV on plant seed production (fecundity tolerance) and life period (mortality tolerance), both measured as a norm of reaction across viral loads (range tolerance). Also, we analysed resistance-tolerance and tolerance-tolerance trade-offs. Results indicate that tolerance to TuMV is associated with changes in the length of the pre-reproductive and reproductive periods, and tolerance to CMV with resource reallocation from growth to reproduction; and that tolerance to TuMV is traded-off against tolerance to CMV in a virulence-dependent manner. Thus, this work provides novel insights on the mechanisms of plant tolerance and highlights the importance of considering the combined effect of different pathogens to understand how plant defences evolve.

Chromatin structure changes in Daphnia populations upon exposure to environmental cues – or – The discovery of Wolterecks “Matrix”

Phenotypic plasticity is an important feature of biological systems that is likely to play a major role in the future adaptation of organisms to the ongoing global changes. It may allow an organism to produce alternative phenotypes in responses to environmental cues. Modifications in the phenotype can be reversible but are sometimes enduring and can even span over generations. The notion of phenotypic plasticity was conceptualized in the early 20th century by Richard Woltereck. He introduced the idea that the combined relations of a phenotypic character and all environmental gradients that influence on it can be defined as “norm of reaction”. Norms of reaction are specific to species and to lineages within species, and they are heritable. He postulated that reaction norms can progressively be shifted over generations depending on the environmental conditions. One of his biological models was the water-flee daphnia. Woltereck proposed that enduring phenotypic modifications and gene mutations could have similar adaptive effects, and he postulated that their molecular bases would be different. Mutations occurred in genes, while enduring modifications were based on something he called the Matrix. He suggested that this matrix (i) was associated with the chromosomes, (ii) that it was heritable, (iii) it changed during development of the organisms, and (iv) that changes of the matrix could be simple chemical substitutions of an unknown, but probably polymeric molecule. We reasoned that the chromatin has all postulated features of this matrix and revisited Woltereck’s classical experiments with daphnia. We developed a robust and rapid ATAC-seq technique that allows for analyzing chromatin of individual daphnia and show here (i) that this technique can be used with minimal expertise in molecular biology, and (ii) we used it to identify open chromatin structure in daphnia exposed to different environmental cues. Our result indicates that chromatin structure changes consistently in daphnia upon this exposure confirming Woltereck’s classical postulate.

Trade-offs between host tolerances to different pathogens in plant-virus interactions

Although accumulating evidence indicates that tolerance is a plant defence strategy against pathogens as widespread as resistance, how plants evolve tolerance is poorly understood. Theory predicts that hosts will evolve to maximize tolerance or resistance, but not both. Remarkably, most experimental works failed in finding this trade-off. We tested the hypothesis that the evolution of tolerance to one virus is traded-off against tolerance to others, rather than against resistance, and identified the associated mechanisms. To do so, we challenged eighteen Arabidopsis thaliana genotypes with Turnip mosaic virus (TuMV) and Cucumber mosaic virus (CMV). We characterized plant life-history trait modifications associated with reduced effects of TuMV and CMV on plant seed production (fecundity tolerance) and life period (mortality tolerance), both measured as a norm of reaction across viral loads (range tolerance). Also, we analysed resistance-tolerance and tolerance-tolerance trade-offs. Results indicate that tolerance to TuMV is associated with changes in the length of the pre-reproductive and reproductive periods, and tolerance to CMV with resource reallocation from growth to reproduction; and that tolerance to TuMV is traded-off against tolerance to CMV in a virulence-dependent manner. Thus, this work provides novel insights on the mechanisms of plant tolerance and highlights the importance of considering the combined effect of different pathogens to understand how plant defences evolve.

Ecological stability of varieties of winter rye with various type of a short-stem

Results 10 years' (2008-2017) comparative studying of varieties of winter rye with recessive-polygenic (the first group) and dominant- monogenic (the second group) short-stem type are presented. In each group tested 5 varieties which estimated on 6 traits: productivity, winter hardiness, plant height, weight is 1000 grains, number of falling and viscosity of water extract of grain meal. Determined by each trait: stability of a phenotype (SF), ecological variation (CV), ecological plasticity (bi), general (GAА) and specific (SAА) adaptive ability, selection value of a genotype (SVG). Average productivity on groups of varieties was identical (respectively 6,69 and 6,62 t/ha), however varieties with dominant-monogenic type of a short-stem differed authentically in the best winter hardiness of plants (for 6,3%) and had shorter stalk (on 9,3 cm). On the ecological variation of traits was influenced significantly by all three factors: weather conditions of year (75,5-95,0%), variety genotype (1,1-2,5%) and interaction variety x years (2,9-22,3%). The most strongly weather conditions of year influenced a productivity variation (86,3% for the first group and 95,0% for the second). On the trait of winter hardiness force of influence of a factor a variety x years was higher, than on other traits, and made respectively 9,3 and 22,3%. Ecological stability at varieties of the second group was twice higher (CV=12,4%), than at varieties of the first group (CV=24,3%). The conclusion is made that varieties of winter rye with a dominant-monogenic short-stem have lower norm of reaction to the adverse conditions of a rewintering developing in years with a high snow cover. Therefore regions where the main limiting factor is the low rewintering because of strong defeat of plants a snow mold have to be the main area of cultivation of such varieties of winter rye. The opinion is expressed that in the main winter rye regions of Russia it is expedient to cultivate varieties of winter rye with different types of a short-stem, but taking into account their agroecological specifics.

Developmental integration and evolution of labile plasticity in a complex quantitative character in a multiperiodic environment

Labile plasticity in a complex quantitative character is modeled, with multiple components contributing to net plasticity in the character. Each component has a specific development rate, norm of reaction, and cost of plasticity. For example, thermal adaptation in mammals includes seasonal fat deposition and fur growth, short-term shivering and sweating or panting, and movement between warm and cold sites. Norms of reaction do not reveal patterns of developmental integration, which must be investigated by studies of developmental dynamics in a changing environment. In a periodic environment, a labile character with a single component of plasticity is constrained by filtering environmental frequencies above the development rate and by the cost of plasticity. With multiple components of plasticity, some patterns of integration can alleviate these constraints to greatly improve fidelity of the mean phenotype tracking multiperiodic cycles in the optimum phenotype. This occurs by environmental signal amplification or inhibition through developmental integration among components and by an augmented development rate of net plasticity in the character that reduces environmental frequency filtering. When development of a component with high cost of plasticity is regulated partly by the norm of reaction of another component, evolution can diminish the reaction norm slope of the costly component without curtailing its development, thereby reducing the loss of fitness from its cost of plasticity. Apparent maladaptation in a component of plasticity may be an integral part of an adaptive pattern of developmental integration by mutual inhibition between components and compensatory evolution of a negative component reaction norm slope.