The regulation of stomatal movements is crucial for plants to optimize gas exchange and water balance. The plant hormone abscisic acid (ABA) triggers stomatal closure in response to drought, effectively minimizing water loss to prevent hydraulic failure. However, it significantly constrains photosynthesis, restricting plant growth and productivity. Therefore, rapid post-drought stomatal opening is crucial for earlier photosynthetic recovery. This review explores how phytohormones or plant growth regulators reverse ABA-induced stomatal closure. Phytomelatonin, 5-aminolevulinic acid, and brassinosteroids promote stomatal reopening by either ABA degradation or suppressing its biosynthesis through the downregulation of corresponding genes. This results in less ABA-induced H2O2 accumulation in guard cells, which lowers H2O2-triggered Ca2+ levels in guard cells, and promotes the opening of KAT1 (K+ in channels). Insights from this review highlight the potential mechanisms of stomatal reopening for earlier post-drought gas exchange recovery, offering potential avenues to enhance plant productivity under changing environmental conditions.

• Klíčová slova
• 5-aminolevulinic acid, abscisic acid, brassinosteroids, drought stress, photosynthesis, phytomelatonin, stomata,
• MeSH
• brassinosteroidy * metabolismus   farmakologie   MeSH
• kyselina abscisová * metabolismus   farmakologie   MeSH
• kyselina aminolevulová * metabolismus   farmakologie   MeSH
• melatonin * metabolismus   farmakologie   MeSH
• období sucha * MeSH
• průduchy rostlin * fyziologie   účinky léků   MeSH
• regulátory růstu rostlin * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• brassinosteroidy * MeSH
• kyselina abscisová * MeSH
• kyselina aminolevulová * MeSH
• melatonin * MeSH
• regulátory růstu rostlin * MeSH

Stomata are crucial structures in plants that play a primary role in the infection process during a pathogen's attack, as they act as points of access for invading pathogens to enter host tissues. Recent evidence has revealed that stomata are integral to the plant defense system and can actively impede invading pathogens by triggering plant defense responses. Stomata interact with diverse pathogen virulence factors, granting them the capacity to influence plant susceptibility and resistance. Moreover, recent studies focusing on the environmental and microbial regulation of stomatal closure and opening have shed light on the epidemiology of bacterial diseases in plants. Bacteria and fungi can induce stomatal closure using pathogen-associated molecular patterns (PAMPs), effectively preventing entry through these openings and positioning stomata as a critical component of the plant's innate immune system; however, despite this defense mechanism, some microorganisms have evolved strategies to overcome stomatal protection. Interestingly, recent research supports the hypothesis that stomatal closure caused by PAMPs may function as a more robust barrier against pathogen infection than previously believed. On the other hand, plant stomatal closure is also regulated by factors such as abscisic acid and Ca2+-permeable channels, which will also be discussed in this review. Therefore, this review aims to discuss various roles of stomata during biotic and abiotic stress, such as insects and water stress, and with specific context to pathogens and their strategies for evading stomatal defense, subverting plant resistance, and overcoming challenges faced by infectious propagules. These pathogens must navigate specific plant tissues and counteract various constitutive and inducible resistance mechanisms, making the role of stomata in plant defense an essential area of study.

• Klíčová slova
• abscisic acid, biotic and abiotic stresses, cytosolic Ca2+, defense mechanisms, signaling components, stomatal responses,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

For tens of millions of years (Ma), the terrestrial habitats of Snowball Earth during the Cryogenian period (between 720 and 635 Ma before present-Neoproterozoic Era) were possibly dominated by global snow and ice cover up to the equatorial sublimative desert. The most recent time-calibrated phylogenies calibrated not only on plants but on a comprehensive set of eukaryotes indicate that within the Streptophyta, multicellular charophytes (Phragmoplastophyta) evolved in the Mesoproterozoic to the early Neoproterozoic. At the same time, Cryogenian is the time of the likely origin of the common ancestor of Zygnematophyceae and Embryophyta and later, also of the Zygnematophyceae-Embryophyta split. This common ancestor is proposed to be called Anydrophyta; here, we use anydrophytes. Based on the combination of published phylogenomic studies and estimated diversification time comparisons, we deem it highly likely that anydrophytes evolved in response to Cryogenian cooling. Also, later in the Cryogenian, secondary simplification of multicellular anydrophytes and loss of flagella resulted in Zygnematophyceae diversification as an adaptation to the extended cold glacial environment. We propose that the Marinoan geochemically documented expansion of first terrestrial flora has been represented not only by Chlorophyta but also by Streptophyta, including the anydrophytes, and later by Zygnematophyceae, thriving on glacial surfaces until today. It is possible that multicellular early Embryophyta survived in less abundant (possibly relatively warmer) refugia, relying more on mineral substrates, allowing the retention of flagella-based sexuality. The loss of flagella and sexual reproduction by conjugation evolved in Zygnematophyceae and zygomycetous fungi during the Cryogenian in a remarkably convergent way. Thus, we support the concept that the important basal cellular adaptations to terrestrial environments were exapted in streptophyte algae for terrestrialization and propose that this was stimulated by the adaptation to glacial habitats dominating the Cryogenian Snowball Earth. Including the glacial lifestyle when considering the rise of land plants increases the parsimony of connecting different ecological, phylogenetic, and physiological puzzles of the journey from aquatic algae to terrestrial floras.

• Klíčová slova
• Anydrophyta, Charophyta, Cryogenian glaciation, Embryophyta, Snowball Earth, Streptophyta, Zygnematophyceae, plant evolution,
• Publikační typ
• časopisecké články MeSH

Monitoring the photosynthetic performance of plants is a major key to understanding how plants adapt to their growth conditions. Stress tolerance traits have a high genetic complexity as plants are constantly, and unavoidably, exposed to numerous stress factors, which limits their growth rates in the natural environment. Arabidopsis thaliana, with its broad genetic diversity and wide climatic range, has been shown to successfully adapt to stressful conditions to ensure the completion of its life cycle. As a result, A. thaliana has become a robust and renowned plant model system for studying natural variation and conducting gene discovery studies. Genome wide association studies (GWAS) in restructured populations combining natural and recombinant lines is a particularly effective way to identify the genetic basis of complex traits. As most abiotic stresses affect photosynthetic activity, chlorophyll fluorescence measurements are a potential phenotyping technique for monitoring plant performance under stress conditions. This review focuses on the use of chlorophyll fluorescence as a tool to study genetic variation underlying the stress tolerance responses to abiotic stress in A. thaliana.

• Publikační typ
• časopisecké články MeSH