: Jasmonic acid (JA) and its related derivatives are ubiquitously occurring compounds of land plants acting in numerous stress responses and development. Recent studies on evolution of JA and other oxylipins indicated conserved biosynthesis. JA formation is initiated by oxygenation of α-linolenic acid (α-LeA, 18:3) or 16:3 fatty acid of chloroplast membranes leading to 12-oxo-phytodienoic acid (OPDA) as intermediate compound, but in Marchantiapolymorpha and Physcomitrellapatens, OPDA and some of its derivatives are final products active in a conserved signaling pathway. JA formation and its metabolic conversion take place in chloroplasts, peroxisomes and cytosol, respectively. Metabolites of JA are formed in 12 different pathways leading to active, inactive and partially active compounds. The isoleucine conjugate of JA (JA-Ile) is the ligand of the receptor component COI1 in vascular plants, whereas in the bryophyte M. polymorpha COI1 perceives an OPDA derivative indicating its functionally conserved activity. JA-induced gene expressions in the numerous biotic and abiotic stress responses and development are initiated in a well-studied complex regulation by homeostasis of transcription factors functioning as repressors and activators.

• Klíčová slova
• JA biosynthetic enzymes, JA bypass, JA signaling, Jasmonic acid (JA) metabolites, active JA compounds, occurrence, transcription factors,
• MeSH
• chloroplasty metabolismus   MeSH
• cyklopentany metabolismus   MeSH
• druhová specificita MeSH
• kyselina alfa-linolenová metabolismus   MeSH
• Marchantia metabolismus   MeSH
• mastné kyseliny metabolismus   MeSH
• mechy metabolismus   MeSH
• metabolické sítě a dráhy MeSH
• nenasycené mastné kyseliny metabolismus   MeSH
• oxylipiny metabolismus   MeSH
• peroxizomy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• 12-oxophytodienoic acid MeSH Prohlížeč
• cyklopentany MeSH
• jasmonic acid MeSH Prohlížeč
• kyselina alfa-linolenová MeSH
• mastné kyseliny MeSH
• nenasycené mastné kyseliny MeSH
• oxylipiny MeSH

Wounding, one of the most intensive stresses influencing plants ontogeny and lifespan, can be induced by herbivory as well as by physical factors. Reactive oxygen species play indispensable role both in the local and systemic defense reactions which enable "reprogramming" of metabolic pathways to set new boundaries and physiological equilibrium suitable for survival. In our current study, we provide experimental evidence on the formation of singlet oxygen (1O2) after wounding of Arabidopsis leaves. It is shown that 1O2 is formed by triplet-triplet energy transfer from triplet carbonyls to molecular oxygen. Using lipoxygenase inhibitor catechol, it is demonstrated that lipid peroxidation is initiated by lipoxygenase. Suppression of 1O2 formation in lox2 mutant which lacks chloroplast lipoxygenase indicates that lipoxygenase localized in chloroplast is predominantly responsible for 1O2 formation. Interestingly, 1O2 formation is solely restricted to chloroplasts localized at the wounding site. Data presented in this study might provide novel insight into wound-induced signaling in the local defense reaction.

• MeSH
• Arabidopsis MeSH
• fenotyp MeSH
• fluorescenční protilátková technika MeSH
• konfokální mikroskopie MeSH
• lipoxygenasa metabolismus   MeSH
• lipoxygenasy genetika   MeSH
• mastné kyseliny metabolismus   MeSH
• molekulární zobrazování MeSH
• mutace MeSH
• proteiny huseníčku genetika   MeSH
• rány a poranění metabolismus   MeSH
• singletový kyslík metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• lipoxygenasa MeSH
• lipoxygenase 2, Arabidopsis MeSH Prohlížeč
• lipoxygenasy MeSH
• mastné kyseliny MeSH
• proteiny huseníčku MeSH
• singletový kyslík MeSH

BACKGROUND: Asexual reproduction has the potential to enhance deleterious mutation accumulation and to constrain adaptive evolution. One source of mutations that can be especially relevant in recent asexuals is activity of transposable elements (TEs), which may have experienced selection for high transposition rates in sexual ancestor populations. Predictions of genomic divergence under asexual reproduction therefore likely include a large contribution of transposable elements but limited adaptive divergence. For plants empirical insight into genome divergence under asexual reproduction remains limited. Here, we characterize expression divergence between clone members of a single apomictic lineage of the common dandelion (Taraxacum officinale) to contribute to our knowledge of genome evolution under asexuality. RESULTS: Using RNA-Seq, we show that about one third of heritable divergence within the apomictic lineage is driven by TEs and TE-related gene activity. In addition, we identify non-random transcriptional differences in pathways related to acyl-lipid and abscisic acid metabolisms which might reflect functional divergence within the apomictic lineage. We analyze SNPs in the transcriptome to assess genetic divergence between the apomictic clone members and reveal that heritable expression differences between the accessions are not explained simply by genome-wide genetic divergence. CONCLUSION: The present study depicts a first effort towards a more complete understanding of apomictic plant genome evolution. We identify abundant TE activity and ecologically relevant functional genes and pathways affecting heritable within-lineage expression divergence. These findings offer valuable resources for future work looking at epigenetic silencing and Cis-regulation of gene expression with particular emphasis on the effects of TE activity on asexual species' genome.

• MeSH
• anotace sekvence MeSH
• jednonukleotidový polymorfismus MeSH
• molekulární evoluce * MeSH
• nepohlavní rozmnožování genetika   MeSH
• populační genetika MeSH
• regulace genové exprese u rostlin MeSH
• RNA rostlin genetika   MeSH
• sekvenční analýza RNA MeSH
• Taraxacum genetika   MeSH
• transkriptom * MeSH
• transpozibilní elementy DNA MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Německo MeSH
• Názvy látek
• RNA rostlin MeSH
• transpozibilní elementy DNA MeSH

Jasmonates (JAs) are lipid-derived signals in plant stress responses and development. A crucial step in JA biosynthesis is catalyzed by allene oxide cyclase (AOC). Four genes encoding functional AOCs (AOC1, AOC2, AOC3 and AOC4) have been characterized for Arabidopsis thaliana in terms of organ- and tissue-specific expression, mutant phenotypes, promoter activities and initial in vivo protein interaction studies suggesting functional redundancy and diversification, including first hints at enzyme activity control by protein-protein interaction. Here, these analyses were extended by detailed analysis of recombinant proteins produced in Escherichia coli. Treatment of purified AOC2 with SDS at different temperatures, chemical cross-linking experiments and protein structure analysis by molecular modelling approaches were performed. Several salt bridges between monomers and a hydrophobic core within the AOC2 trimer were identified and functionally proven by site-directed mutagenesis. The data obtained showed that AOC2 acts as a trimer. Finally, AOC activity was determined in heteromers formed by pairwise combinations of the four AOC isoforms. The highest activities were found for heteromers containing AOC4 + AOC1 and AOC4 + AOC2, respectively. All data are in line with an enzyme activity control of all four AOCs by heteromerization, thereby supporting a putative fine-tuning in JA formation by various regulatory principles.

• Klíčová slova
• Arabidopsis allene oxide cyclase isoforms, activity regulation, heteromerization, protein structure analysis, site-directed mutagenesis,
• Publikační typ
• časopisecké články MeSH