The root apical meristem (RAM) is the plant stem cell niche which provides for the formation and continuous development of the root. Auxin is the main regulator of RAM functioning, and auxin maxima ...coincide with the sites of RAM initiation and maintenance. Auxin gradients are formed due to local auxin biosynthesis and polar auxin transport. The PIN family of auxin transporters plays a critical role in polar auxin transport, and two mechanisms of auxin maximum formation in the RAM based on PIN-mediated auxin transport have been proposed to date: the reverse fountain and the reflected flow mechanisms.
The two mechanisms are combined here in in silico studies of auxin distribution in intact roots and roots cut into two pieces in the proximal meristem region. In parallel, corresponding experiments were performed in vivo using DR5::GFP Arabidopsis plants.
The reverse fountain and the reflected flow mechanism naturally cooperate for RAM patterning and maintenance in intact root. Regeneration of the RAM in decapitated roots is provided by the reflected flow mechanism. In the excised root tips local auxin biosynthesis either alone or in cooperation with the reverse fountain enables RAM maintenance.
The efficiency of a dual-mechanism model in guiding biological experiments on RAM regeneration and maintenance is demonstrated. The model also allows estimation of the concentrations of auxin and PINs in root cells during development and under various treatments. The dual-mechanism model proposed here can be a powerful tool for the study of several different aspects of auxin function in root.
Leaves of many angiosperm species develop trichomes. These epidermal outgrowths have been exploited to the study the determination of cell fate, plant cell differentiation mechanisms and cell ...morphogenesis in the model plant species. It was found that even simple shape trichomes (leaf hairs) offer protection against both biotic and abiotic stress factors. Currently, in monocotyledonous plants, the genetic basis of leaf hair formation is poorly understood. This study sought to establish the genetic control of leaf pubescence formation in bread wheat (Triticum aestivum L.) in terms of leaf hair patterning and growth. A set of cultivars and lines carrying allelic combinations of three pubescence controlling genes, Hl1, Hl3 and Hl2 ᵃᵉˢᵖ was used for quantitative phenotyping. It was demonstrated that these genes differ in their effect on leaf hair formation: Hl1 and Hl3 more affected leaf hair initiation and growth, while Hl2 ᵃᵉˢᵖ modified leaf hair length. Their action was independent to a large extent. A model of Hl1, Hl3 and Hl2 ᵃᵉˢᵖ genes action is proposed.
The variation in structure and function of gene regulatory networks (GRNs) participating in organisms development is a key for understanding species-specific evolutionary strategies. Even the tiniest ...modification of developmental GRN might result in a substantial change of a complex morphogenetic pattern. Great variety of trichomes and their accessibility makes them a useful model for studying the molecular processes of cell fate determination, cell cycle control and cellular morphogenesis. Nowadays, a large number of genes regulating the morphogenesis of A. thaliana trichomes are described. Here we aimed at a study the evolution of the GRN defining the trichome formation, and evaluation its importance in other developmental processes.
In study of the evolution of trichomes formation GRN we combined classical phylogenetic analysis with information on the GRN topology and composition in major plants taxa. This approach allowed us to estimate both times of evolutionary emergence of the GRN components which are mainly proteins, and the relative rate of their molecular evolution. Various simplifications of protein structure (based on the position of amino acid residues in protein globula, secondary structure type, and structural disorder) allowed us to demonstrate the evolutionary associations between changes in protein globules and speciations/duplications events. We discussed their potential involvement in protein-protein interactions and GRN function.
We hypothesize that the divergence and/or the specialization of the trichome-forming GRN is linked to the emergence of plant taxa. Information about the structural targets of the protein evolution in the GRN may predict switching points in gene networks functioning in course of evolution. We also propose a list of candidate genes responsible for the development of trichomes in a wide range of plant species.
Cold and drought are two of the most severe threats affecting the growth and productivity of the tea plant, limiting its global spread. Both stresses cause osmotic changes in the cells of the tea ...plant by decreasing their water potential. To develop cultivars that are tolerant to both stresses, it is essential to understand the genetic responses of tea plant to these two stresses, particularly in terms of the genes involved. In this study, we combined literature data with interspecific transcriptomic analyses (using
and
) to choose genes related to cold tolerance. We identified 45 stress-inducible candidate genes associated with cold and drought responses in tea plants based on a comprehensive homologous detection method. Of these, nine were newly characterized by us, and 36 had previously been reported. The gene network analysis revealed upregulated expression in
-related cluster of
factors,
connected genes (hexokinases, galactinol synthases,
complex, etc.) indicating their possible co-expression. Using qRT-PCR we revealed that 10 genes were significantly upregulated in response to both cold and drought in tea plant:
, and
.
were specifically upregulated in cold, while
were specifically upregulated in drought. Interestingly, the expression of
was higher in the recovery stage of both stresses, indicating its potentially important role in plant recovery after stress. In addition, some genes, such as
, and
, were significantly positively correlated between the cold and drought responses.
, and
, by contrast, showed significantly negative correlations between the cold and drought responses. Our results provide valuable information and robust candidate genes for future functional analyses intended to improve the stress tolerance of the tea plant and other species.
Phenomics is a field of science at the junction of biology and informatics which solves the problems of rapid, accurate estimation of the plant phenotype; it was rapidly developed because of the need ...to analyze phenotypic characteristics in large scale genetic and breeding experiments in plants. It is based on using the methods of computer image analysis and integration of biological data. Owing to automation, new approaches make it possible to considerably accelerate the process of estimating the characteristics of a phenotype, to increase its accuracy, and to remove a subjectivism (inherent to humans). The main technologies of high-throughput plant phenotyping in both controlled and field conditions, their advantages and disadvantages, and also the prospects of their use for the efficient solution of problems of plant genetics and breeding are presented in the review.
Marine protists are an important part of the ocean ecosystem. They may possess unique sets of biosynthetic pathways and, thus, be promising model organisms for metabolic engineering for producing ...substances for the pharmaceutical, cosmetic, and perfume industries. Currently, full-genome data are available just for a limited number of protists hampering their use in biotechnology.
We characterized the morphology of a new cultured strain of Thraustochytriaceae isolated from the Black Sea ctenophore
using phase-contrast microscopy. Cell culture was performed in the FAND culture medium based on fetal bovine serum and DMEM. Phylogenetic analysis was performed using the 18S rRNA sequence. We also conducted a transcriptome assembly and compared the data with the closest species.
The protist belongs to the genus
based on the 18S rRNA sequence analysis. We designated the isolated protist as
. The closest species with the genome assembly is
. Transcriptome analysis revealed the majority of the fatty acid synthesis enzymes.
Our findings suggest that the
is a promising candidate for biotechnological use. Together with the previously available, our data would allow the establishment of an accurate phylogeny of the family Thraustochytriaceae. Also, it could be a reference point for studying the evolution of the enzyme families.
In this study, genetic and monosomic analyses of the leaf pubescence of ANK 7A, ANK 7B, and ANK 7C wheat isogenic lines were carried out based on the Novosibirskaya 67 wheat variety. According to ...visual analysis, the recipient variety has a soft, uniform pubescence, and lines have trichomes on the surfaces of their leaves inherited from the two Chinese varieties and one Soviet variety. Using the high throughput phenotyping method LHDetect2, which allows one to allocate the phenotypic classes of offspring in crosses based on the quantitative characteristics of leaf pubescence, it was found that chromosome 7B of the isogenic lines has a gene that determines the presence of long trichomes, and chromosome 7D of the Novosibirskaya 67 variety has a gene that increases the density of pubescence. The obtained data allowed to formulate of a hypothesis for the existence of a homoallelic series of genes that control leaf pubescence in the chromosomes of the seventh homeologous group of bread wheat.
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