Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Iron (Fe) is essential for plant growth and development. Knowledge of Fe signaling, from the beginning of perception to activation of the uptake process, is critical for crop improvement. Here, by using chemical screening, we identified a small molecule 3-amino-N-(3-methylphenyl)thieno[2,3-b]pyridine-2-carboxamide named R7 ('R' denoting repressor of IRON-REGULATED TRANSPORTER 1), that modulates Fe homeostasis of Arabidopsis. R7 treatment led to reduced Fe levels in plants, thus causing severe chlorosis under Fe deficiency. Expression analysis of central transcription factors, FER-LIKE IRON DEFICIENCY INDUCED TRANSCRIPTION FACTOR (FIT) and subgroup Ib basic helix-loop-helix (Ib bHLH) genes bHLH38/39/100/101, revealed that R7 targets the FIT-dependent transcriptional pathway. Exogenously supplying S-nitrosoglutathione (GSNO), but not other nitric oxide (NO) donors sodium nitroprusside (SNP) and S-nitroso-N-acetyl-dl-penicillamine (SANP), alleviated the inhibitory effects of R7 on Fe homeostasis. R7 did not inhibit cellular levels of NO or glutathione but decreased GSNO level in roots. We demonstrate that NO is involved in regulating not only the FIT transcriptional network but also the Ib bHLH networks. In addition, GSNO, from S-nitrosylation of glutathione, specifically mediates the Fe-starvation signal to FIT, which is distinct from the NO to Ib bHLH signal. Our work dissects the molecular connection between NO and the Fe-starvation response. We present a new signaling route whereby GSNO acts downstream of NO to trigger the Fe-deficiency response in Arabidopsis.
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PMID:S-Nitrosoglutathione works downstream of nitric oxide to mediate iron-deficiency signaling in Arabidopsis. 2939 86

Plant growth requires optimal levels of iron (Fe). Fe is used for energy production, numerous enzymatic processes, and is indispensable for cellular metabolism. Recent studies have established the mechanism involved in Fe uptake and transport. However, our knowledge of Fe sensing and signaling is limited. Dissecting Fe signaling may be useful for crop improvement by Fe fortification. Here, we report two small-molecules, R3 and R6 [where R denotes repressor of IRON-REGULATED TRANSPORTER 1 (IRT1)], identified through a chemical screening, whose use blocked activation of the Fe-deficiency response in Arabidopsis thaliana. Physiological analysis of plants treated with R3 and R6 showed that these small molecules drastically attenuated the plant response to Fe starvation. Small-molecule treatment caused severe chlorosis and strongly reduced chlorophyll levels in plants. Fe content in shoots was decreased considerably by small-molecule treatments especially in Fe deficiency. Small-molecule treatments attenuated the Fe-deficiency-induced expression of the Fe uptake gene IRT1. Analysis of FER-LIKE IRON-DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) and subgroup Ib basic helix-loop-helix (bHLH) gene (bHLH38/39/100/101) expression showed that R3 affects the FIT-network, whereas R6 affects both the FIT and Ib bHLH networks. An assessment of the effects of the structural analogs of R3 and R6 on the induction of Fe-dependent chlorosis revealed the functional motif of the investigated chemicals. Our findings suggest that small-molecules selectively modulate the distinct signaling routes that operate in response to Fe-deficiency. R3 and R6 likely interrupt the activity of key upstream signaling regulators whose activities are required for the activation of the Fe-starvation transcriptional cascade in Arabidopsis roots.
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PMID:Small-Molecules Selectively Modulate Iron-Deficiency Signaling Networks in Arabidopsis. 3076 41