Thesis
The AHL gene family and its role in flowering time, hypocotyl length, seed size and seed weight in Arabidopsis and Camelina
Washington State University
Master of Science (MS), Washington State University
07/2019
DOI:
https://doi.org/10.7273/000000045
Handle:
https://hdl.handle.net/2376/118929
Abstract
Seed size and weight can impact several agronomic aspects of crops, such as, yield,
dispersal, planting, harvesting and seedling establishment, especially under adverse conditions
(like drought, weed and pest pressure etc.). Camelina (Camelina sativa L.) and canola (Brassica
napus L.) are promising oil seed crops that can be incorporated into rotation with cereal crops in
dryland cultivation. However, the smaller seed size for these crops can have a negative impact
on emergence and successful seedling establishment in dryland farming. Developing varieties
with bigger seeds and longer hypocotyls can be beneficial for improving emergence, stand
establishment and yield by allowing deeper planting depths to access available soil moisture.
Seed size is a complex trait controlled by various genes. In this study we demonstrate that some
of the AHL (At-hook Containing, Nuclear Localized) genes play crucial roles in determining the
seed size and weight and hypocotyl length in Arabidopsis (Arabidopsis thaliana; L.) and Camelina.
Overexpression of the Suppressor of Phytochrome B-4 #3 (Atsob3-D/AtAHL29) or its closest relative AtESCAROLA (AtESC/AtAHL27) represses seed weight and hypocotyl elongation. In
contrast, overexpression of the alleles sob3-6 and esc-11, which are caused by a missense point
mutation that disrupts DNA binding, leads to larger and heavier seeds and taller seedlings
compared to the wild type in Arabidopsis. Overexpression of Atsob3-6 increases seed weight by
50% and hypocotyl elongation by 100%. Similarly, overexpression of Atesc-11 increases seed
weight by 25% and hypocotyl length by 50% compared to the wild type in Arabidopsis. In
addition, overexpression of Atsob3-6 confers ~30% bigger and 50% heavier seeds and 50% longer
hypocotyls compared to the wild type in Camelina. The resulting larger Camelina seeds enhance
seedling emergence when planted deeper in soil. Some of the AHLs, such as AtAHL6 and AtAHL20
also control the flowering time, another important agronomic trait. Taken together, AHL genes
could be promising targets to develop oil seed cultivars suitable for the inland Pacific Northwest’s
dryland cropping systems.
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Details
- Title
- The AHL gene family and its role in flowering time, hypocotyl length, seed size and seed weight in Arabidopsis and Camelina
- Creators
- Pushpa Sharma Koirala
- Contributors
- MICHAEL NEFF (Degree Supervisor) - Washington State University, Crop and Soil Sciences, Department ofSCOT HOWARD HULBERT (Committee Member) - Washington State University, Plant Pathology, Department ofKAREN SANGUINET (Committee Member) - Washington State University, Crop and Soil Sciences, Department of
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Format
- pdf
- Number of pages
- 89
- Identifiers
- 99900590963101842
- Language
- English
- Resource Type
- Thesis