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Increased expression of the MYB‐related transcription factor, PHR1 , leads to enhanced phosphate uptake in Arabidopsis thaliana
Author(s) -
NILSSON LENA,
MÜLLER RENATE,
NIELSEN TOM HAMBORG
Publication year - 2007
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2007.01734.x
Subject(s) - mutant , myb , transcription factor , starvation response , biology , gene , gene expression , arabidopsis , arabidopsis thaliana , microbiology and biotechnology , meristem , wild type , biochemistry , genetics
Plants have evolved a number of adaptive strategies to cope with fluctuations in phosphorus (P) supply. The current knowledge of the transcriptional regulation of the P‐starvation response in plants is limited. However, one MYB‐related transcription factor, PHR1, is known to be involved in the P‐starvation response. In this paper, we characterize a T‐tagged phr1 knockout mutant and a series of transgenic plant lines which over‐express PHR1 in wild type (WT) and phr1 mutant background. The knockout mutant has an altered phosphate (P i ) allocation between root and shoot; accumulates less anthocyanins, sugars and starch than P‐starved WT; has a lower AGPase activity; and is impaired in induction of a subset of P i starvation‐induced genes. Expression of PHR1 in the phr1 mutant rescues the responsiveness to P‐starvation and leads to WT levels of sugars and starch during P i starvation conditions, confirming the involvement of PHR1 in adjusting carbon metabolism. Over‐expression of PHR1 further resulted in a dramatic increase in the microRNA miR399d , and this resulted in changes in the transcript level for the target gene PHO2 . Furthermore, over‐expression of PHR1 in both WT and phr1 mutant results in strongly increased content of P i irrespective of P regime. This shows that targeting a key regulatory element in the P i starvation regulatory network represents a useful approach for molecular breeding of plants towards more efficient P i uptake and assimilation.