Chromatin-based processes are essential for cellular functions. Structural maintenance of chromosomes (SMCs) are evolutionarily conserved molecular machines that organize chromosomes throughout the cell cycle, mediate chromosome compaction, promote DNA repair, or control sister chromatid attachment. The SMC5/6 complex is known for its pivotal role during the maintenance of genome stability. However, a dozen recent plant studies expanded the repertoire of SMC5/6 complex functions to the entire plant sexual reproductive phase. The SMC5/6 complex is essential in meiosis, where its activity must be precisely regulated to allow for normal meiocyte development. Initially, it is attenuated by the recombinase RAD51 to allow for efficient strand invasion by the meiosis-specific recombinase DMC1. At later stages, it is essential for the normal ratio of interfering and non-interfering crossovers, detoxifying aberrant joint molecules, preventing chromosome fragmentation, and ensuring normal chromosome/sister chromatid segregation. The latter meiotic defects lead to the production of diploid male gametes in Arabidopsis SMC5/6 complex mutants, increased seed abortion, and production of triploid offspring. The SMC5/6 complex is directly involved in controlling normal embryo and endosperm cell divisions, and pioneer studies show that the SMC5/6 complex is also important for seed development and normal plant growth in cereals.

• Klíčová slova
• SMC5/6 complex, fertility, genome stability, meiosis, polyploidy, reproductive development, seed,
• MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• chromatidy metabolismus   MeSH
• meióza MeSH
• oprava DNA MeSH
• proteiny buněčného cyklu * genetika   metabolismus   MeSH
• rekombinasy genetika   MeSH
• rozmnožování genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• proteiny buněčného cyklu * MeSH
• rekombinasy MeSH

Epigenetics has emerged as an important research field for crop improvement under the on-going climatic changes. Heritable epigenetic changes can arise independently of DNA sequence alterations and have been associated with altered gene expression and transmitted phenotypic variation. By modulating plant development and physiological responses to environmental conditions, epigenetic diversity-naturally, genetically, chemically, or environmentally induced-can help optimise crop traits in an era challenged by global climate change. Beyond DNA sequence variation, the epigenetic modifications may contribute to breeding by providing useful markers and allowing the use of epigenome diversity to predict plant performance and increase final crop production. Given the difficulties in transferring the knowledge of the epigenetic mechanisms from model plants to crops, various strategies have emerged. Among those strategies are modelling frameworks dedicated to predicting epigenetically controlled-adaptive traits, the use of epigenetics for in vitro regeneration to accelerate crop breeding, and changes of specific epigenetic marks that modulate gene expression of traits of interest. The key challenge that agriculture faces in the 21st century is to increase crop production by speeding up the breeding of resilient crop species. Therefore, epigenetics provides fundamental molecular information with potential direct applications in crop enhancement, tolerance, and adaptation within the context of climate change.

• Klíčová slova
• DNA methylation, breeding, climate change, epigenomics, memory, plant epigenetics, prediction models, priming,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Herbicide resistance is broadly recognized as the adaptive evolution of weed populations to the intense selection pressure imposed by the herbicide applications. Here, we tested whether transcriptional gene silencing (TGS) and RNA-directed DNA Methylation (RdDM) pathways modulate resistance to commonly applied herbicides. Using Arabidopsis thaliana wild-type plants exposed to sublethal doses of glyphosate, imazethapyr, and 2,4-D, we found a partial loss of TGS and increased susceptibility to herbicides in six out of 11 tested TGS/RdDM mutants. Mutation in REPRESSOR OF SILENCING 1 (ROS1), that plays an important role in DNA demethylation, leading to strongly increased susceptibility to all applied herbicides, and imazethapyr in particular. Transcriptomic analysis of the imazethapyr-treated wild type and ros1 plants revealed a relation of the herbicide upregulated genes to chemical stimulus, secondary metabolism, stress condition, flavonoid biosynthesis, and epigenetic processes. Hypersensitivity to imazethapyr of the flavonoid biosynthesis component TRANSPARENT TESTA 4 (TT4) mutant plants strongly suggests that ROS1-dependent accumulation of flavonoids is an important mechanism for herbicide stress response in A. thaliana. In summary, our study shows that herbicide treatment affects transcriptional gene silencing pathways and that misregulation of these pathways makes Arabidopsis plants more sensitive to herbicide treatment.

• Klíčová slova
• 2,4-D, ROS1, chromatin mutants, epigenetics, glyphosate, herbicide resistance, imazethapyr,
• MeSH
• acyltransferasy genetika   MeSH
• Arabidopsis účinky léků   genetika   MeSH
• chromatin chemie   MeSH
• demetylace DNA MeSH
• genetická transkripce MeSH
• herbicidy farmakologie   MeSH
• jaderné proteiny genetika   MeSH
• kyselina 2,4-dichlorfenoxyoctová farmakologie   MeSH
• kyseliny nikotinové farmakologie   MeSH
• metylace DNA MeSH
• mutace MeSH
• proteiny huseníčku genetika   MeSH
• regulace genové exprese u rostlin * MeSH
• RNA rostlin genetika   MeSH
• sekvenování transkriptomu MeSH
• umlčování genů * MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acyltransferasy MeSH
• AT5G13930 protein, Arabidopsis MeSH Prohlížeč
• chromatin MeSH
• herbicidy MeSH
• imazethapyr MeSH Prohlížeč
• jaderné proteiny MeSH
• kyselina 2,4-dichlorfenoxyoctová MeSH
• kyseliny nikotinové MeSH
• proteiny huseníčku MeSH
• RNA rostlin MeSH
• ROS1 protein, Arabidopsis MeSH Prohlížeč