A Chimeric Arabinogalactan Protein Promotes Somatic Embryogenesis in Cotton Cell Culture
Arabinogalactan proteins (AGPs) are a family of extracellular plant proteoglycans implicated in many aspects of plant growth and development, including in vitro somatic embryogenesis (SE). We found that specific AGPs were produced by cotton (Gossypiutn hirsutum) calli undergoing SE and that when the...
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Published in | Plant physiology (Bethesda) Vol. 160; no. 2; pp. 684 - 695 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Rockville, MD
American Society of Plant Biologists
01.10.2012
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Subjects | |
Online Access | Get full text |
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Summary: | Arabinogalactan proteins (AGPs) are a family of extracellular plant proteoglycans implicated in many aspects of plant growth and development, including in vitro somatic embryogenesis (SE). We found that specific AGPs were produced by cotton (Gossypiutn hirsutum) calli undergoing SE and that when these AGPs were isolated and incorporated into tissue culture medium, cotton SE was promoted. When the AGPs were partly or fully deglycosylated, SE-promoting activity was not diminished. Testing of AGPs separated by reverse-phase high-performance liquid chromatography revealed that the SEpromoting activity resided in a hydrophobic fraction. We cloned a full-length complementary DNA (cotton PHYTOCYANINLIKE ARABINOGALACTAN-PROTEIN1 [GhPLA1]) that encoded the protein backbone of an AGP in the active fraction. It has a chimeric structure comprising an amino-terminal signal sequence, a phytocyanin-like domain, an AGP-like domain, and a hydrophobic carboxyl-terminal domain. Recombinant production of GhPLAl in tobacco (Nicotiana tabacum) cells enabled us to purify and analyze a single glycosylated AGP and to demonstrate that this chimeric AGP promotes cotton SE. Furthermore, the nonglycosylated phytocyanin-like domain from GhPLAl, which was bacterially produced, also promoted SE, indicating that the glycosylated AGP domain was unnecessary for in vitro activity. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0032-0889 1532-2548 1532-2548 |
DOI: | 10.1104/pp.112.203075 |