| RRC ID |
606
|
| Author |
Sakakibara H, Kasahara H, Ueda N, Kojima M, Takei K, Hishiyama S, Asami T, Okada K, Kamiya Y, Yamaya T, Yamaguchi S.
|
| Title |
Agrobacterium tumefaciens increases cytokinin production in plastids by modifying the biosynthetic pathway in the host plant.
|
| Journal |
Proc Natl Acad Sci U S A
|
| Abstract |
Agrobacterium tumefaciens infects plants and induces the formation of tumors called "crown galls" by integrating the transferred-DNA (T-DNA) region of the Ti-plasmid into the plant nuclear genome. Tumors are formed because the T-DNA encodes enzymes that modify the synthesis of two plant growth hormones, auxin and cytokinin (CK). Here, we show that a CK biosynthesis enzyme, Tmr, which is encoded by the Agrobacterium T-DNA region, is targeted to and functions in plastids of infected plant cells, despite having no typical plastid-targeting sequence. Evidence is provided that Tmr is an adenosine phosphate-isopentenyltransferase (IPT) that creates a new CK biosynthesis bypass by using 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate (HMBDP) as a substrate. Unlike in the conventional CK biosynthesis pathway in plants, trans-zeatin-type CKs are produced directly without the requirement for P450 monooxygenase-mediated hydroxylation. Consistent with the plastid localization of Tmr, HMBDP is an intermediate in the methylerythritol phosphate pathway, a plastid-localized biosynthesis route for universal isoprenoid precursors. These results demonstrate that A. tumefaciens modifies CK biosynthesis by sending a key enzyme into plastids of the host plant to promote tumorigenesis.
|
| Volume |
102(28)
|
| Pages |
9972-7
|
| Published |
2005-7-12
|
| DOI |
10.1073/pnas.0500793102
|
| PII |
0500793102
|
| PMID |
15998742
|
| PMC |
PMC1174980
|
| MeSH |
Adenine Nucleotides / metabolism
Agrobacterium tumefaciens / enzymology*
Alkyl and Aryl Transferases / metabolism*
Arabidopsis / microbiology*
Bacterial Proteins / metabolism*
Blotting, Western
Cytokinins / biosynthesis*
Genetic Vectors
Green Fluorescent Proteins
Oncogene Proteins / metabolism*
Organophosphates / metabolism
Plant Tumor-Inducing Plasmids / genetics*
Plant Tumors / genetics*
Plant Tumors / microbiology
|
| IF |
9.412
|
| Times Cited |
78
|
|
WOS Category
|
PLANT SCIENCES
|
| Resource |
| Arabidopsis / Cultured plant cells, genes |
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