Skip to Main Content
Frequently Asked Questions
Submit an ETD
Global Search Box
Need Help?
Keyword Search
Participating Institutions
Advanced Search
School Logo
Files
File List
ohiou1226474401.pdf (2.96 MB)
ETD Abstract Container
Abstract Header
Functional Characterization of Lysine-rich Arabinogalactan-Proteins (AGPs) and an AG Peptide in Arabidopsis
Author Info
Zhang, Yizhu
Permalink:
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1226474401
Abstract Details
Year and Degree
2008, Doctor of Philosophy (PhD), Ohio University, Environmental and Plant Biology (Arts and Sciences).
Abstract
The plant cell wall is composed of complex polysaccharides and a small amount of structural proteins and cell wall enzymes. Arabinogalactan-proteins (AGPs) are highly glycosylated, hydroxyproline-rich structural proteins that play important roles in plant growth and development.
AtAGP17, 18
and
19
comprise the lysine-rich classical AGP family in
Arabidopsis
. They consist of an N-terminal signal peptide, a classical AGP domain disrupted by a short basic lysine-rich subdomain and a C-terminal glycosylphosphatidylinositol (GPI) anchor addition sequence. A previous study showed a null T-DNA insertion mutant of
AtAGP19
displayed pleiotropic phenotypes. Here, a microarray approach was employed to elucidate changes in gene expression associated with the
atagp19
mutant. The expression of several genes related to cell expansion were found to change significantly. Interestingly, one gene (
At1g68720
, cytidine/deoxycytidylate deaminase family protein) adjacent to
AtAGP19
was found to be down-regulated about 50 fold and RT-PCR showed the absence of mRNA for this gene in the
atagp19
mutant. Furthermore, complementation with the 3' portion of the
At1g68720
gene can fully restore all the wild type phenotypes, indicating this region is critical for the functions revealed by the
agp19
mutant. To examine cellular localization of the lysine-rich AGPs, GFP-AtAGP17/18/19 fusion proteins as well as a GFP control were overexpressed in Arabidopsis plants and the fusion proteins were present on the plant cell surface. Plasmolysis of leaf trichome cells further determined the localization of the fusion proteins at the plasma membrane. Moreover, in vitro pollen germination showed that AtAGP17, unlike LeAGP-1 (the lysine-rich AGP in tomato), was not associated with pollen tube elongation. To further elucidate AtAGP17/18/19 function(s), transgenic Arabidopsis overexpressing AtAGP17/18/19 without the GFP tag were produced. AtAGP18 overexpressors displayed several phenotypes distinct from the wild type plants: they were short and bushy, had short roots and produced less viable seeds. In contrast, the vector control transformants as well as the AtAGP17/19 overexpressors had the same phenotypes as the wild type plants. Furthermore,
AtAGP18
was down-regulated by the plant hormone ABA, indicating ABA may be involved in AtAGP18 function(s). Finally, the expression pattern of AtAGP14 (At5g56540), an AG peptide in Arabidopsis was examined. AtAGP14 was highly expressed in flowers and young roots and moderately expressed in seedlings, stems and rosette leaves. A plate-based phenotypic analysis was also carried out for the T-DNA insertional mutant of
AtAGP14
and wild type
Arabidopsis
but no significant differences were observed with respect to germination rate, true leaf numbers, primary root length and lateral root numbers.
Committee
Allan M. Showalter (Advisor)
Sarah Wyatt (Other)
Ahmed Faik (Other)
Marcia Kieliszewski (Other)
Pages
160 p.
Subject Headings
Biology
;
Molecular Biology
Keywords
Arabidopsis
;
arabinogalactan-proteins
;
lysine-rich AGPs
;
microarray
;
overexpression
;
GPI anchor
Recommended Citations
Refworks
EndNote
RIS
Mendeley
Citations
Zhang, Y. (2008).
Functional Characterization of Lysine-rich Arabinogalactan-Proteins (AGPs) and an AG Peptide in Arabidopsis
[Doctoral dissertation, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1226474401
APA Style (7th edition)
Zhang, Yizhu.
Functional Characterization of Lysine-rich Arabinogalactan-Proteins (AGPs) and an AG Peptide in Arabidopsis.
2008. Ohio University, Doctoral dissertation.
OhioLINK Electronic Theses and Dissertations Center
, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1226474401.
MLA Style (8th edition)
Zhang, Yizhu. "Functional Characterization of Lysine-rich Arabinogalactan-Proteins (AGPs) and an AG Peptide in Arabidopsis." Doctoral dissertation, Ohio University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1226474401
Chicago Manual of Style (17th edition)
Abstract Footer
Document number:
ohiou1226474401
Download Count:
543
Copyright Info
© 2008, all rights reserved.
This open access ETD is published by Ohio University and OhioLINK.