Linked Life Data

18034312

Source:http://linkedlifedata.com/resource/pubmed/id/18034312

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
2007-12-17
pubmed:abstractText
Rice plants (Oryza sativa L.) take up iron using iron-chelating compounds known as mugineic acid family phytosiderophores (MAs). In the biosynthetic pathway of MAs, nicotianamine aminotransferase (NAAT) catalyses the key step from nicotianamine to the 3''-keto form. In the present study, we identified six rice NAAT genes (OsNAAT1-6) by screening a cDNA library made from Fe-deficient rice roots and by searching databases. Among the NAAT homologues, OsNAAT1 belongs to a subgroup containing barley functional NAAT (HvNAAT-A and HvNAAT-B) as well as a maize homologue cloned by cDNA library screening (ZmNAAT1). Northern blot and RT-PCR analysis showed that OsNAAT1, but not OsNAAT2-6, was strongly up-regulated by Fe deficiency, both in roots and shoots. The OsNAAT1 protein had NAAT enzyme activity in vitro, confirming that the OsNAAT1 gene encodes functional NAAT. Promoter-GUS analysis revealed that OsNAAT1 was expressed in companion and pericycle cells adjacent to the protoxylem of Fe-sufficient roots. In addition, expression was induced in all cells of Fe-deficient roots, with particularly strong GUS activity evident in the companion and pericycle cells. OsNAAT1 expression was also observed in the companion cells of Fe-sufficient shoots, and was clearly induced in all the cells of Fe-deficient leaves. These expression patterns highly resemble those of OsNAS1, OsNAS2 and OsDMAS1, the genes responsible for MAs biosynthesis for Fe acquisition. These findings strongly suggest that rice synthesizes MAs in whole Fe-deficient roots to acquire Fe from the rhizosphere, and also in phloem cells to maintain metal homeostasis facilitated by MAs-mediated long-distance transport.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0167-4412
pubmed:author
pubmed:issnType
Print
pubmed:volume
66
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
193-203
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Identification and localisation of the rice nicotianamine aminotransferase gene OsNAAT1 expression suggests the site of phytosiderophore synthesis in rice.
pubmed:affiliation
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
pubmed:publicationType
Journal Article