Plant microgametogenesis involves stages leading to the progressive development of unicellular microspores into mature pollen. Despite the active and continuing interest in the study of male reproductive development, little is still known about the hormonomics at each ontogenetic stage. In this work, we characterized the profiles and dynamics of phytohormones during the process of microgametogenesis in four Nicotiana species (Nicotiana tabacum, Nicotiana alata, Nicotiana langsdorffii, and Nicotiana mutabilis). Taking advantage of advanced HPLC-ESI-MS/MS, twenty to thirty endogenous hormone derivatives were identified throughout pollen ontogenesis, including cytokinins, auxins, ABA and its derivatives, jasmonates, and phenolic compounds. The spectra of endogenous phytohormones changed dynamically during tobacco pollen ontogeny, indicating their important role in pollen growth and development. The different dynamics in the accumulation of endogenous phytohormones during pollen ontogenesis between N. tabacum (section Nicotiana) and the other three species (section Alatae) reflects their different phylogenetic positions and origin within the genus Nicotiana. We demonstrated the involvement of certain phytohormone forms, such as cis-zeatin- and methylthiol-type CKs, some derivatives of abscisic acid, phenylacetic and benzoic acids, in pollen development for the first time here. Our results suggest that unequal levels of endogenous hormones and the presence of specific derivatives may be characteristic for pollen development in different phylogenetic plant groups. These results represent the currently most comprehensive study of plant hormones during the process of pollen development.

• Klíčová slova
• Nicotiana spp., hormonome, male gametophyte, ontogeny, phytohormones, pollen development,
• Publikační typ
• časopisecké články 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