Comparative analysis of stomatal development networks in Arabidopsis and Brachypodium
Abstract/Contents
- Abstract
- Stomata, epidermal valves made up of paired guard cells flanking a central pore, are found in most aerial tissues of plants, where they function to regulate gas exchange. Production of mature stomata involves a series of asymmetric cell divisions (ACDs) and cell fate transitions, and the molecular genetic regulation of this process has been extensively studied in the dicot Arabidopsis thaliana (thale cress). Yet, it remains largely unknown whether the same genetic regulators are used across a range of taxa, and how genes and networks might differ between species to produce (or accommodate) distinct developmental patterns. Indeed, stomatal ontogeny is remarkably diverse among plant species, with particularly intriguing differences between dicots and grasses. Whereas Arabidopsis stomata are sprinkled across the leaf surface seemingly at random, grasses produce stomata oriented along the leaf axis in specific linear cell files. In my thesis work, I have examined the genetic networks controlling stomatal development in grasses, focusing particularly on how these networks resemble or differ from those of Arabidopsis. My studies are conducted using the forage grass Brachypodium distachyon, a recently developed, genetically tractable model species related to wheat and barley. First, I report the basic characterization of Brachypodium stomatal development, as well as the identification of stomatal mutants via a forward genetic screen. Subsequently, I describe mutations in two orthologues of known Arabidopsis stomatal regulators: the bHLH gene BdICE1, which is required for production of mature stomata, and the MAPKKK gene BdYDA1, which enforces correct stomatal patterning. Although both mutants resemble their Arabidopsis counterparts, their phenotypes suggest subtly but intriguingly different roles in Brachypodium. BdICE1, unlike Arabidopsis ICE1, is not functionally redundant with its paralogue BdSCRM2, and the two Brachypodium genes have roles in promoting GMC and guard cell identity, respectively. Further, preliminary data suggest that the ICEs of Brachypodium may differ from those of Arabidopsis in their interactions with SPCH family bHLHs. Similarly, although BdYDA1, like Arabidopsis YDA, enforces stomatal patterning, it also regulates a number of other asymmetrically dividing epidermal cell lineages (e.g., hair and silica cell lineages), suggesting a role as a general regulator of fate asymmetry. Finally, I discuss prospects for using timelapse imaging and computational modeling to gain insight into stomatal lineage polarity, division, and fate specification processes in both dicots and grasses.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2014 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Abrash, Emily |
|---|---|
| Associated with | Stanford University, Department of Biology. |
| Primary advisor | Bergmann, Dominique |
| Thesis advisor | Bergmann, Dominique |
| Thesis advisor | Axelrod, Jeffrey (Jeffrey David) |
| Thesis advisor | Long, Sharon |
| Thesis advisor | Walbot, Virginia |
| Advisor | Axelrod, Jeffrey (Jeffrey David) |
| Advisor | Long, Sharon |
| Advisor | Walbot, Virginia |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Emily Abrash. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2014. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2014 by Emily Abrash
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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