Virginia Tech
Characterization of signaling pathways underlying key growth and development processes in Populus trichocarpa
Abstract
dc:description.abstractThe project goals for this dissertation were to manipulate Populus trichocarpa source-sink relationships to optimize this woody crop species for specific agricultural traits such as increased growth rate, stress tolerance and/or improvements in overall biomass accumulation. We targeted specific tissues such as xylem, where alterations in the relationship of source and sink tissues can lead to the control of xylem cell deposition or of various wood properties. This led to the characterization of 165 protein-protein interactions and 20 protein-DNA interaction which constitute numerous woody tissue related subnetworks. One such network, centered on the DIVARACATA and RADIALIS INTERACTING FACTOR (PtrDRIF), identified PtrWOX13c as an interacting protein. Characterization of PtrWOX13c shows that it displays the ability to control promoters related to lignin biosynthesis genes and overexpression phenotypes show alterations in axillary branch activity. Genes which control the differentiation and specialization of cells such as members of the WOX family are also highly responsive to abiotic stress which can force major changes in plant metabolism and nutrient mobilization. ABA, a prominent plant phytohormone with known roles in the adaptation to stress has shown novel connections in the regulation of growth promoting complexes such as TOR through antagonistic regulatory actions of the SnRK2 protein kinase in Arabidopsis. Characterization of the core ABA signaling in P. trichocarpa has identified a regulatory clade A protein phosphatase which interacts with numerous PtrSnRK2 proteins and when overexpressed in hybrid poplar results in increased height and node production potentially by indirect control of growth promoting complexes like TOR through SnRK2 inhibition. This work has also demonstrated that in addition to the involvement of phytohormones in the regulation of plant development, sugar phosphates such as T6P can exert significant control of plant architecture. Together, these studies comprise the discovery and subsequent characterization of novel wood associated networks, hormone pathways and sugar signaling in the manipulation of P. trichocarpa source-sink relationships for the promotion of biomass accumulation.
Degree
thesis:*- Name thesis:degree_name
- PHD
- Level thesis:degree_level
- doctoral
- Discipline thesis:degree_discipline
- Horticulture
- Department dc:contributor.department
- Horticulture
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2018
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Rigoulot, Stephen Bradley
- Chair dc:contributor.committeechair
-
- Beers, Eric P.
- Committee members dc:contributor.committeemember
-
- Zhao, Bingyu
- Pilot, Guillaume
- Brunner, Amy Marie
Subjects
dc:subject × 7Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
Identifiers
dc:identifier.*- Dc Identifier Other
- vt_gsexam:16834
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/97078