Sexual reproduction in flowering plants depends on the fitness of the male gametophyte during fertilization. Because pollen development is highly sensitive to hot and cold temperature extremes, reliable methods to evaluate pollen viability are important for research into improving reproductive heat stress (HS) tolerance. Here, we describe an approach to rapidly evaluate pollen viability using a reactive oxygen species (
Reactive oxygen species (ROS) can serve as signaling molecules that are essential for plant growth and development but abiotic stress can lead to ROS increases to supraoptimal levels resulting in cellular damage. To ensure efficient ROS signaling, cells have machinery to locally synthesize ROS to initiate cellular responses and to scavenge ROS to prevent it from reaching damaging levels. This review summarizes experimental evidence revealing the role of ROS during multiple stages of plant reproduction. Localized ROS synthesis controls the formation of pollen grains, pollen−stigma interactions, pollen tube growth, ovule development, and fertilization. Plants utilize ROS‐producing enzymes such as respiratory burst oxidase homologs and organelle metabolic pathways to generate ROS, while the presence of scavenging mechanisms, including synthesis of antioxidant proteins and small molecules, serves to prevent its escalation to harmful levels. In this review, we summarized the function of ROS and its synthesis and scavenging mechanisms in all reproductive stages from gametophyte development until completion of fertilization. Additionally, we further address the impact of elevated temperatures induced ROS on impairing these reproductive processes and of flavonol antioxidants in maintaining ROS homeostasis to minimize temperature stress to combat the impact of global climate change on agriculture.
more » « less- Award ID(s):
- 1939255
- NSF-PAR ID:
- 10488268
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Plant, Cell & Environment
- ISSN:
- 0140-7791
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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<bold>Summary</bold> ROS ) probe dichlorodihydrofluorescein diacetate (i.e. H2DCFDA ‐staining) coupled with flow cytometry. In using flow cytometry to analyze mature pollen harvested from Arabidopsis and tomato flowers, we discovered that pollen distributed bimodally into ‘low‐ROS ’ and ‘high‐ROS ’ subpopulations. Pollen germination assays following fluorescence‐activated cell sorting revealed that the high‐ROS pollen germinated with a frequency that was 35‐fold higher than the low‐ROS pollen, supporting a model in which a significant fraction of a flower's pollen remains in a low metabolic or dormant state even after hydration. The ability to use flow cytometry to quantifyROS dynamics within a large pollen population was shown by dose‐dependent alterations inDCF ‐fluorescence in response to oxidative stress or antioxidant treatments. HS treatments (35°C) increasedROS levels, which correlated with a ~60% reduction in pollen germination. These results demonstrate the potential of using flow cytometry‐based approaches to investigate metabolic changes during stress responses in pollen. -
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SUMMARY Schrenkiella parvula , a leading extremophyte model in Brassicaceae, can grow and complete its lifecycle under multiple environmental stresses, including high salinity. Yet, the key physiological and structural traits underlying its stress‐adapted lifestyle are unknown along with trade‐offs when surviving salt stress at the expense of growth and reproduction. We aimed to identify the influential adaptive trait responses that lead to stress‐resilient and uncompromised growth across developmental stages when treated with salt at levels known to inhibit growth in Arabidopsis and most crops. Its resilient growth was promoted by traits that synergistically allowed primary root growth in seedlings, the expansion of xylem vessels across the root‐shoot continuum, and a high capacity to maintain tissue water levels by developing thicker succulent leaves while enabling photosynthesis during salt stress. A successful transition from vegetative to reproductive phase was initiated by salt‐induced early flowering, resulting in viable seeds. Self‐fertilization in salt‐induced early flowering was dependent upon filament elongation in flowers otherwise aborted in the absence of salt during comparable plant ages. The maintenance of leaf water status promoting growth, and early flowering to ensure reproductive success in a changing environment, were among the most influential traits that contributed to the extremophytic lifestyle ofS. parvula . -
null (Ed.)Plant isoprene emissions are known to contribute to abiotic stress tolerance, especially during episodes of high temperature and drought, and during cellular oxidative stress. Recent studies have shown that genetic transformations to add or remove isoprene emissions cause a cascade of cellular modifications that include known signaling pathways, and interact to remodel adaptive growth-defense tradeoffs. The most compelling evidence for isoprene signaling is found in the shikimate and phenylpropanoid pathways, which produce salicylic acid, alkaloids, tannins, anthocyanins, flavonols and other flavonoids; all of which have roles in stress tolerance and plant defense. Isoprene also influences key gene expression patterns in the terpenoid biosynthetic pathways, and the jasmonic acid, gibberellic acid and cytokinin signaling networks that have important roles in controlling inducible defense responses and influencing plant growth and development, particularly following defoliation. In this synthesis paper, using past studies of transgenic poplar, tobacco and Arabidopsis, we present the evidence for isoprene acting as a metabolite that coordinates aspects of cellular signaling, resulting in enhanced chemical defense during periods of climate stress, while minimizing costs to growth. This perspective represents a major shift in our thinking away from direct effects of isoprene, for example, by changing membrane properties or quenching ROS, to indirect effects, through changes in gene expression and protein abundances. Recognition of isoprene’s role in the growth-defense tradeoff provides new perspectives on evolution of the trait, its contribution to plant adaptation and resilience, and the ecological niches in which it is most effective.more » « less
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Abstract The molecular machinery for protein synthesis is profoundly similar between plants and other eukaryotes. Mechanisms of translational gene regulation are embedded into the broader network of RNA‐level processes including RNA quality control and RNA turnover. However, over eons of their separate history, plants acquired new components, dropped others, and generally evolved an alternate way of making the parts list of protein synthesis work. Research over the past 5 years has unveiled how plants utilize translational control to defend themselves against viruses, regulate translation in response to metabolites, and reversibly adjust translation to a wide variety of environmental parameters. Moreover, during seed and pollen development plants make use of RNA granules and other translational controls to underpin developmental transitions between quiescent and metabolically active stages. The economics of resource allocation over the daily light–dark cycle also include controls over cellular protein synthesis. Important new insights into translational control on cytosolic ribosomes continue to emerge from studies of translational control mechanisms in viruses. Finally, sketches of coherent signaling pathways that connect external stimuli with a translational response are emerging, anchored in part around TOR and GCN2 kinase signaling networks. These again reveal some mechanisms that are familiar and others that are different from other eukaryotes, motivating deeper studies on translational control in plants.
This article is categorized under:
Translation > Translation Regulation
RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems
RNA Interactions with Proteins and Other Molecules > Protein‐RNA Interactions: Functional Implications
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