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Summary Plants integrate environmental stimuli to optimize photosynthesis vs water loss by controlling stomatal apertures. However, stomatal responses to temperature elevation and the underlying molecular genetic mechanisms remain less studied.We developed an approach for clamping leaf‐to‐air vapor pressure difference (VPDleaf) to fixed values, and recorded robust reversible warming‐induced stomatal opening in intact plants. We analyzed stomatal temperature responses of mutants impaired in guard cell signaling pathways for blue light, abscisic acid (ABA), CO2, and the temperature‐sensitive proteins, Phytochrome B (phyB) and EARLY‐FLOWERING‐3 (ELF3).We confirmed thatphot1‐5/phot2‐1leaves lacking blue‐light photoreceptors showed partially reduced warming‐induced stomatal opening. Furthermore, ABA‐biosynthesis, phyB, and ELF3 were not essential for the stomatal warming response. Strikingly,Arabidopsis(dicot) andBrachypodium distachyon(monocot) mutants lacking guard cell CO2sensors and signaling mechanisms, includinght1,mpk12/mpk4‐gc, andcbc1/cbc2abolished the stomatal warming response, suggesting a conserved mechanism across diverse plant lineages. Moreover, warming rapidly stimulated photosynthesis, resulting in a reduction in intercellular (CO2). Interestingly, further enhancing heat stress caused stomatal opening uncoupled from photosynthesis.We provide genetic and physiological evidence that the stomatal warming response is triggered by increased CO2assimilation and stomatal CO2sensing. Additionally, increasing heat stress functions via a distinct photosynthesis‐uncoupled stomatal opening pathway.
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The plant response to high CO2 levels is heritable and orchestrated by DNA methylation
Summary Plant responses to abiotic environmental challenges are known to have lasting effects on the plant beyond the initial stress exposure. Some of these lasting effects are transgenerational, affecting the next generation. The plant response to elevated carbon dioxide (CO2) levels has been well studied. However, these investigations are typically limited to plants grown for a single generation in a high CO2environment while transgenerational studies are rare.We aimed to determine transgenerational growth responses in plants after exposure to high CO2by investigating the direct progeny when returned to baseline CO2levels.We found that both the flowering plantArabidopsis thalianaand seedless nonvascular plantPhyscomitrium patenscontinue to display accelerated growth rates in the progeny of plants exposed to high CO2. We used the model species Arabidopsis to dissect the molecular mechanism and found that DNA methylation pathways are necessary for heritability of this growth response.More specifically, the pathway of RNA‐directed DNA methylation is required to initiate methylation and the proteins CMT2 and CMT3 are needed for the transgenerational propagation of this DNA methylation to the progeny plants. Together, these two DNA methylation pathways establish and then maintain a cellular memory to high CO2exposure.
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- Award ID(s):
- 1921724
- PAR ID:
- 10403670
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 238
- Issue:
- 6
- ISSN:
- 0028-646X
- Format(s):
- Medium: X Size: p. 2427-2439
- Size(s):
- p. 2427-2439
- Sponsoring Org:
- National Science Foundation
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