Seed Priming: New Comprehensive Approaches for an Old Empirical Technique

Seed priming is a pre-sowing treatment which leads to a physiological state that enables seed to germinate more efficiently. The majority of seed treatments are based on seed imbibition allowing the seeds to go through the first reversible stage of germination but do not allow radical protrusion through the seed coat. Seeds keeping their desiccation tolerance are then dehydrated and can be stored until final sowing. During subsequent germination, primed seeds exhibit a faster and more synchronized germination and young seedlings are often more vigorous and resistant to abiotic stresses than seedlings obtained from unprimed seeds. Priming often involves soaking seed in predetermined amounts of water or limitation of the imbibition time. The imbibition rate could be somehow controlled by osmotic agents such as PEG and referred as osmopriming. Halopriming implies the use of specific salts while "hormopriming" relies on the use of plant growth regulators. Some physical treatments (UV, cold or heat,..) also provide germination improvement thus suggesting that priming effects are not necessarily related to seed imbibition. A better understanding of the metabolic events taking place during the priming treatment and the subsequent germination should help to use this simple and cheap technology in a more efficient way

Epigenetic Landmarks of Leaf Senescence and Crop Improvement.

This review synthesizes knowledge on epigenetic regulation of leaf senescence and discusses the possibility of using this knowledge to improve crop quality. This control level is implemented by different but interacting epigenetic mechanisms, including DNA methylation, covalent histone modifications, and non-covalent chromatin remodeling. The genetic and epigenetic changes may act alone or together and regulate the gene expression, which may result in heritable (stress memory) changes and may lead to crop survival. In the review, the question also arises whether the mitotically stable epigenetic information can be used for crop improvement. The barley crop model for early and late events of dark-induced leaf senescence (DILS), where the point of no return was defined, revealed differences in DNA and RNA modifications active in DILS compared to developmental leaf senescence. This suggests the possibility of a yet-to-be-discovered epigenetic-based switch between cell survival and cell death. Conclusions from the analyzed research contributed to the hypothesis that chromatin-remodeling mechanisms play a role in the control of induced leaf senescence. Understanding this mechanism in crops might provide a tool for further exploitation toward sustainable agriculture: so-called epibreeding

The SWI/SNF ATP-Dependent Chromatin Remodeling Complex in Arabidopsis Responds to Environmental Changes in Temperature-Dependent Manner

SWI/SNF ATP-dependent chromatin remodeling complexes (CRCs) play important roles in the regulation of transcription, cell cycle, DNA replication, repair, and hormone signaling in eukaryotes. The core of SWI/SNF CRCs composed of a SWI2/SNF2 type ATPase, a SNF5 and two of SWI3 subunits is sufficient for execution of nucleosome remodeling in vitro. The Arabidopsis genome encodes four SWI2/SNF2 ATPases, four SWI3, a single SNF5 and two SWP73 subunits. Genes of the core SWI/SNF components have critical but not fully overlapping roles during plant growth, embryogenesis, and sporophyte development. Here we show that the Arabidopsis swi3c mutant exhibits a phenotypic reversion when grown at lower temperature resulting in partial restoration of its embryo, root development and fertility defects. Our data indicates that the swi3c mutation alters the expression of several genes engaged in low temperature responses. The location of SWI3C-containing SWI/SNF CRCs on the ICE1, MYB15 and CBF1 target genes depends on the temperature conditions, and the swi3c mutation thus also influences the transcription of several cold-responsive (COR) genes. These findings, together with genetic analysis of swi3c/ice1 double mutant and enhanced freezing tolerance of swi3c plants illustrate that SWI/SNF CRCs contribute to fine tuning of plant growth responses to different temperature regimes

The SWI/SNF ATP-Dependent Chromatin Remodeling Complex in Arabidopsis Responds to Environmental Changes in Temperature-Dependent Manner

SWI/SNF ATP-dependent chromatin remodeling complexes (CRCs) play important roles in the regulation of transcription, cell cycle, DNA replication, repair, and hormone signaling in eukaryotes. The core of SWI/SNF CRCs composed of a SWI2/SNF2 type ATPase, a SNF5 and two of SWI3 subunits is sufficient for execution of nucleosome remodeling in vitro. The Arabidopsis genome encodes four SWI2/SNF2 ATPases, four SWI3, a single SNF5 and two SWP73 subunits. Genes of the core SWI/SNF components have critical but not fully overlapping roles during plant growth, embryogenesis, and sporophyte development. Here we show that the Arabidopsis swi3c mutant exhibits a phenotypic reversion when grown at lower temperature resulting in partial restoration of its embryo, root development and fertility defects. Our data indicates that the swi3c mutation alters the expression of several genes engaged in low temperature responses. The location of SWI3C-containing SWI/SNF CRCs on the ICE1, MYB15 and CBF1 target genes depends on the temperature conditions, and the swi3c mutation thus also influences the transcription of several cold-responsive (COR) genes. These findings, together with genetic analysis of swi3c/ice1 double mutant and enhanced freezing tolerance of swi3c plants illustrate that SWI/SNF CRCs contribute to fine-tuning of plant growth responses to different temperature regimes

Physio-Genetic Dissection of Dark-Induced Leaf Senescence and Timing Its Reversal in Barley.

Barley crop model was analyzed for early and late events during the dark-induced leaf senescence (DILS) as well as for deciphering critical time limit for reversal of the senescence process. Chlorophyll fluorescence vitality index Rfd was determined as the earliest parameter that correlated well with the cessation of photosynthesis prior to microautophagy symptoms, initiation of DNA degradation, and severalfold increase in the endonuclease BNUC1. DILS was found characterized by up-regulation of processes that enable recycling of degraded macromolecules and metabolites, including increased NH4+ remobilization, gluconeogenesis, glycolysis, and partial up-regulation of glyoxylate and tricarboxylate acid cycles. The most evident differences in gene medleys between DILS and developmental senescence included hormone-activated signaling pathways, lipid catabolic processes, carbohydrate metabolic processes, low-affinity ammonia remobilization, and RNA methylation. The mega-autophagy symptoms were apparent much later, specifically on day 10 of DILS, when disruption of organelles—nucleus and mitochondria —became evident. Also, during this latter-stage programmed cell death processes, namely, shrinking of the protoplast, tonoplast interruption, and vacuole breakdown, chromatin condensation, more DNA fragmentation, and disintegration of the cell membrane were prominent. Reversal of DILS by re-exposure of the plants from dark to light was possible until but not later than day 7 of dark exposure and was accompanied by regained photosynthesis, increase in chlorophyll, and reversal of Rfd, despite activation of macro-autophagy-related genes

Advanced adenoid cystic carcinoma (ACC) is featured by SWI/SNF chromatin remodeling complex aberrations

Abstract Purpose Adenoid cystic carcinoma (ACC) is a rare neurotropic cancer with slow progression occurring in salivary glands and less frequently in other body parts. ACC is featured by hyperchromatic nuclei and various mutations in genes encoding chromatin-related machineries. The ACC treatment is mainly limited to the radical surgery and radiotherapy while the chemotherapy remains ineffective. As the knowledge about molecular basis of ACC development is limited, we investigated here the molecular features of this disease. Patients and methods This study included 50 patients with ACC. Transcript profiling of available ACC samples vs normal salivary gland tissue, quantitative real-time PCR (qRT-PCR) transcript level measurements and the immunohistochemistry (IHC) for SWI/SNF chromatin remodeling complex (CRC) subunits and androgen receptor on surgery-derived paraffinembedded samples were performed. Results Transcriptomic study followed by Gene Ontology classification indicated alteration of chromatin-related processes, including downregulated transcript levels of main SWI/SNF CRC subunits and elevated expression of BRM ATPase-coding SMARCA2 gene in ACC. Subsequent IHC indicated broad accumulation of BRM ATPase and several SWI/SNF subunits, suggesting affected control of their protein level in ACC. The IHC revealed ectopic, heterogeneous expression of androgen receptor (AR) in some ACC cells. Conclusions Our study indicated that ACC features aberrant expression of genes controlling chromatin status and structure. We found that the balance between SWI/SNF classes is moved towards the BRM ATPase-containing complex in ACC. As BRM is known to be involved in chemoresistance in cancer cells, this observation may be the likely explanation for ACC chemoresistance

PD-L1 Overexpression, SWI/SNF Complex Deregulation, and Profound Transcriptomic Changes Characterize Cancer-Dependent Exhaustion of Persistently Activated CD4+ T Cells

Growing tumors avoid recognition and destruction by the immune system. During continuous stimulation of tumor-infiltrating lymphocytes (TILs) by tumors, TILs become functionally exhausted; thus, they become unable to kill tumor cells and to produce certain cytokines and lose their ability to proliferate. This collectively results in the immune escape of cancer cells. Here, we show that breast cancer cells expressing PD-L1 can accelerate exhaustion of persistently activated human effector CD4+ T cells, manifesting in high PD-1 and PD-L1 expression level son T cell surfaces, decreased glucose metabolism genes, strong downregulation of SWI/SNF chromatin remodelingcomplex subunits, and p21 cell cycle inhibitor upregulation. This results in inhibition of T cell proliferation and reduction of T cell numbers. The RNAseq analysis on exhausted CD4+ T cells indicated strong overexpression of IDO1 and genes encoding pro-inflammatory cytokines and chemokines. Some interleukins were also detected in media from CD4+ T cells co-cultured with cancer cells. The PD-L1 overexpression was also observed in CD4+ T cells after co-cultivation with other cell lines overexpressing PD-L1, which suggested the existence of a general mechanism of CD4+ T cell exhaustion induced by cancer cells. The ChIP analysis on the PD-L1 promoter region indicated that the BRM recruitment in control CD4+ T cells was replaced by BRG1 and EZH2 in CD4+ T cells strongly exhausted by cancer cells. These findings suggest that epi-drugs such as EZH2 inhibitors may be used as immunomodulators in cancer treatment

Molecular and physiological basis of rape (Brassica napus L.) seeds osmopriming

Wydział Biologii: Instytut Biologii EksperymentalnejPrezentowana rozprawa doktorska poświęcona jest zagadnieniu kondycjonowania nasion, w szczególności osmokondycjonowania nasion rzepaku (Brassica napus L.). Celem pracy doktorskiej było poznanie molekularnych i fizjologicznych mechanizmów kondycjonowania odpowiedzialnych za polepszenie parametrów kiełkowania nasion oraz zwiększoną tolerancję na zasolenie. Osmokondycjonowanie znacząco zwiększyło wigor nasion rzepaku. Wyniki analizy transkryptomicznej i proteomicznej wskazują, że wzrost wigoru osmokondycjonowanych nasion może być wynikiem aktywacji procesu syntezy białek, modyfikacji potraslacyjnych i ukierunkowanej proteolizy białek. Ponadto za przyczynę polepszonego kiełkowania kondycjonowanych nasion można uznać podwyższoną ekspresję genów i akumulację białek zaangażowanych w transport wody, modyfikacje ściany komórkowej, organizację cytoszkieletu, podziały komórkowe oraz odpowiedź na stres oksydacyjny. Wyniki uzyskane z analiz dotyczących kiełkowania nasion kondycjonowanych w warunkach stresu zasolenia wskazują, że osmokondycjonowanie zwiększa tolerancję kiełkujących nasion rzepaku na zasolenie. Zwiększona tolerancja nasion osmokondycjonowanych na stres zasolenia może wynikać między innymi z akumulacji proliny, która jest wynikiem indukowanej przez nadtlenek wodoru ekspresji genu P5CSA oraz zwiększonej aktywności enzymu P5CS.The presented PhD thesis is devoted to the seeds priming topic, especially osmopriming of oil rapeseed (Brassica napus L.). The primary goal of PhD thesis was to better understand the molecular and physiological mechanisms underlying osmopriming-induced improvement of seed germination as well as stress tolerance. Osmopriming treatment had beneficial effects on seeds vigor. Transcriptomic and proteomic analyses showed that progress towards germination in osmoprimed seeds was associated with an increase in protein synthesis potential, post-translational processing capacity and targeted proteolysis. Moreover, improved germination performance can be linked to higher expression of genes and proteins involved in water transport, cell wall modification, cytoskeletal organization, cell division and management of oxidative stress. The results of the analysis conducted on seeds germinated under salinity condition showed that osmopriming improved salinity tolerance during germination. This germination performance was linked with Pro accumulation as a result of hydrogen peroxide-induced expression of proline synthesis gene P5CSA and P5CS enzyme activity

Are regional airports economic effectiveness oriented? Evidence from Poland

Are regional airports economic effectiveness-oriented? Evidence from Poland Striving for a satisfactory level of effectiveness, managers must take actions aimed at achieving the set objectives and at reacting flexibly to changes that take place in the environment. They can do it by referring to the concept of dynamic capabilities that draw attention to a specific category of competences. Assuming that dynamic capabilities can be developed in any type of organisation, the article attempts to answer the question about the reasons for the differences in economic effectiveness of 13 Polish regional airports and 458 private enterprises. The results suggest that the category of economic effectiveness is important not only for private enterprises but also for regional airports. The findings reveal that the development of dynamic capabilities is conditioned not only by the period of the enterprise’s existence but also by the context of its operation, primarily the industry context