Sexual reproduction in angiosperms requires the production and delivery of two male gametes by a three-celled haploid male gametophyte. This demands synchronized gene expression in a short developmental window to ensure double fertilization and seed set. While transcriptomic changes in developing pollen are known for Arabidopsis, no studies have integrated RNA and proteomic data in this model. Further, the role of alternative splicing has not been fully addressed, yet post-transcriptional and post-translational regulation may have a key role in gene expression dynamics during microgametogenesis. We have refined and substantially updated global transcriptomic and proteomic changes in developing pollen for two Arabidopsis accessions. Despite the superiority of RNA-seq over microarray-based platforms, we demonstrate high reproducibility and comparability. We identify thousands of long non-coding RNAs as potential regulators of pollen development, hundreds of changes in alternative splicing and provide insight into mRNA translation rate and storage in developing pollen. Our analysis delivers an integrated perspective of gene expression dynamics in developing Arabidopsis pollen and a foundation for studying the role of alternative splicing in this model.

• Klíčová slova
• Arabidopsis, Male gametophyte, Microgametogenesis, Proteome, RNA-seq,
• MeSH
• Arabidopsis * genetika   metabolismus   MeSH
• proteiny huseníčku * genetika   metabolismus   MeSH
• proteomika MeSH
• pyl genetika   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• reprodukovatelnost výsledků MeSH
• transkriptom MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• proteiny huseníčku * MeSH

Being rooted in place, plants are faced with the challenge of responding to unfavourable local conditions. One such condition, heat stress, contributes massively to crop losses globally. Heatwaves are predicted to increase, and it is of vital importance to generate crops that are tolerant to not only heat stress but also to several other abiotic stresses (e.g. drought stress, salinity stress) to ensure that global food security is protected. A better understanding of the molecular mechanisms that underlie the temperature stress response in pollen will be a significant step towards developing effective breeding strategies for high and stable production in crop plants. While most studies have focused on the vegetative phase of plant growth to understand heat stress tolerance, it is the reproductive phase that requires more attention as it is more sensitive to elevated temperatures. Every phase of reproductive development is affected by environmental challenges, including pollen and ovule development, pollen tube growth, male-female cross-talk, fertilization, and embryo development. In this review we summarize how pollen is affected by heat stress and the molecular mechanisms employed during the stress period, as revealed by classical and -omics experiments.

• Klíčová slova
• heat stress (HS), heat stress response (HSR), multiomics, pollen development, thermotolerance,
• MeSH
• fyziologický stres MeSH
• pyl MeSH
• reakce na tepelný šok MeSH
• šlechtění rostlin * MeSH
• termotolerance * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Sexual plant reproduction depends on the production and differentiation of functional gametes by the haploid gametophyte generation. Currently, we have a limited understanding of the regulatory mechanisms that have evolved to specify the gametophytic developmental programs. To unravel such mechanisms, it is necessary to identify transcription factors (TF) that are part of such haploid regulatory networks. Here we focus on bZIP TFs that have critical roles in plants, animals and other kingdoms. We report the functional characterization of Arabidopsis thaliana AtbZIP34 that is expressed in both gametophytic and surrounding sporophytic tissues during flower development. T-DNA insertion mutants in AtbZIP34 show pollen morphological defects that result in reduced pollen germination efficiency and slower pollen tube growth both in vitro and in vivo. Light and fluorescence microscopy revealed misshapen and misplaced nuclei with large lipid inclusions in the cytoplasm of atbzip34 pollen. Scanning and transmission electron microscopy revealed defects in exine shape and micropatterning and a reduced endomembrane system. Several lines of evidence, including the AtbZIP34 expression pattern and the phenotypic defects observed, suggest a complex role in male reproductive development that involves a sporophytic role in exine patterning, and a sporophytic and/or gametophytic mode of action of AtbZIP34 in several metabolic pathways, namely regulation of lipid metabolism and/or cellular transport.

• MeSH
• Arabidopsis genetika   metabolismus   MeSH
• buněčná stěna metabolismus   ultrastruktura   MeSH
• fluorescenční mikroskopie MeSH
• geneticky modifikované rostliny MeSH
• květy genetika   růst a vývoj   metabolismus   MeSH
• metabolické sítě a dráhy genetika   fyziologie   MeSH
• mikroskopie elektronová rastrovací MeSH
• mutace MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proteiny huseníčku genetika   fyziologie   MeSH
• pyl genetika   metabolismus   ultrastruktura   MeSH
• pylová láčka genetika   růst a vývoj   metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• stanovení celkové genové exprese MeSH
• testy genetické komplementace MeSH
• trans-aktivátory genetika   fyziologie   MeSH
• transmisní elektronová mikroskopie MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bZIP34 protein, Arabidopsis MeSH Prohlížeč
• proteiny huseníčku MeSH
• trans-aktivátory MeSH

BACKGROUND: The effective functional analysis of male gametophyte development requires new tools enabling the spatially and temporally controlled expression of both marker genes and modified genes of interest. In particular, promoters driving expression at earlier developmental stages including microspores are required. RESULTS: Transcriptomic datasets covering four progressive stages of male gametophyte development in Arabidopsis were used to select candidate genes showing early expression profiles that were male gametophyte-specific. Promoter-GUS reporter analysis of candidate genes identified three promoters (MSP1, MSP2, and MSP3) that are active in microspores and are otherwise specific to the male gametophyte and tapetum. The MSP1 and MSP2 promoters were used to successfully complement and restore the male transmission of the gametophytic two-in-one (tio) mutant that is cytokinesis-defective at first microspore division. CONCLUSION: We demonstrate the effective application of MSP promoters as tools that can be used to elucidate gametophytic gene functions in microspores in a male-specific manner.

• MeSH
• Arabidopsis genetika   fyziologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• promotorové oblasti (genetika) * MeSH
• regulace genové exprese u rostlin * MeSH
• rostlinné geny * MeSH
• testy genetické komplementace MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH