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Query: UMLS:C0038187 (
starvation
)
24,951
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Nitrogen (N) is often a limiting nutrient whose availability determines plant growth and productivity. Because its availability is often low and/or not uniform over time and space in nature, plants respond to variations in N availability by altering uptake and recycling mechanisms, but the molecular mechanisms underlying how these responses are regulated are poorly understood. Here, we show that a group of GARP G2-like transcription factors,
Arabidopsis thaliana
NITRATE-INDUCIBLE, GARP-
TYPE
TRANSCRIPTIONAL REPRESSOR1/HYPERSENSITIVE TO LOW Pi-ELICITED PRIMARY ROOT SHORTENING1 proteins (NIGT1/HRS1s), are factors that bind to the promoter of the N
starvation
marker
NRT2.4
and repress an array of N
starvation
-responsive genes under conditions of high N availability. Transient assays and expression analysis demonstrated that NIGT1/HRS1s are transcriptional repressors whose expression is regulated by N availability. We identified target genes of the NIGT1/HRS1s by genome-wide transcriptome analyses and found that they are significantly enriched in N
starvation
response-related genes, including N acquisition, recycling, remobilization, and signaling genes. Loss of
NIGT1/HRS1s
resulted in deregulation of N acquisition and accumulation. We propose that NIGT1/HRS1s are major regulators of N
starvation
responses that play an important role in optimizing N acquisition and utilization under fluctuating N conditions.
...
PMID:Repression of Nitrogen Starvation Responses by Members of the Arabidopsis GARP-Type Transcription Factor NIGT1/HRS1 Subfamily. 2962 67
Phosphorus and nitrogen are essential macronutrients for plant growth and crop production. During phosphate (Pi)
starvation
, plants enhanced Pi but reduced nitrate (NO
3
-
) uptake capacity, and the mechanism is unclear. Here, we show that a GARP-type transcription factor NITRATE-INDUCIBLE, GARP-
TYPE
TRANSCRIPTIOANL REPRESSOR1.2 (NIGT1.2) coordinately modulates Pi and NO
3
-
uptake in response to Pi
starvation
. Overexpression of
NIGT1.2
increased Pi uptake capacity but decreased NO
3
-
uptake capacity in Arabidopsis (
Arabidopsis thaliana
). Furthermore, the
nigt1.1 nigt1.2
double mutant displayed reduced Pi uptake but enhanced NO
3
-
uptake under low-Pi stress. During Pi
starvation
, NIGT1.2 directly up-regulated the transcription of the Pi transporter genes
PHOSPHATE TRANSPORTER1;1
(
PHT1;1
) and
PHOSPHATE TRANSPORTER1;4
(
PHT1;4
) and down-regulated expression of NO
3
-
transporter gene
NITRATE TRANSPORTER1.1
(
NRT1.1
) by binding to
cis
-elements in their promoters. Further genetic assays demonstrated that
PHT1;1
,
PHT1;4
, and
NRT1.1
were genetically epistatic to
NIGT1.2
We also identified similar regulatory pathway in maize (
Zea mays
). These data demonstrate that the transcription factor NIGT1.2 plays a central role in modulating low-Pi-dependent uptake of Pi and NO
3
-
, tending toward maintenance of the phosphorus to nitrogen balance in plants during Pi
starvation
.
...
PMID:The Transcription Factor NIGT1.2 Modulates Both Phosphate Uptake and Nitrate Influx during Phosphate Starvation in Arabidopsis and Maize. 3295 62
