MicroRNA399 is a long-distance signal for the regulation of plant phosphate homeostasis

By Bikram Datt Pant, A. Buhtz, J. Kehr, W. Scheible. The Plant Journal, 2008

729 citations recorded by the source corpus.

The presence of microRNA species in plant phloem sap suggests potential signaling roles by long-distance regulation of gene expression. Proof for such a role for a phloem-mobile microRNA is lacking. Here we show that phosphate (Pi) starvation-induced microRNA399 (miR399) is present in the phloem sap of two diverse plant species, rapeseed and pumpkin, and levels are strongly and specifically increased in phloem sap during Pi deprivation. By performing micro-grafting experiments using Arabidopsis, we further show that chimeric plants constitutively over-expressing miR399 in the shoot accumulate mature miR399 species to very high levels in their wild-type roots, while corresponding primary transcripts are virtually absent in roots, demonstrating shoot-to-root transport. The chimeric plants exhibit (i) down-regulation of the miR399 target transcript (PHO2), which encodes a critical component for maintenance of Pi homeostasis, in the wild-type root, and (ii) Pi accumulation in the shoot, which is the phenotype of pho2 mutants, miR399 over-expressers or chimeric plants with a genetic knock-out of PHO2 in the root. Hence the transported miR399 molecules retain biological activity. This is a demonstration of systemic control of a biological process, i.e. maintenance of plant Pi homeostasis, by a phloem-mobile microRNA.

Subfields: Plant Science

View Paper: https://www.semanticscholar.org/paper/1e69240ebadece289d59186ad56676691f80b09c

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Citations in the corpus

Signaling network in sensing phosphate availability in plants. (2011, methodology): “Importantly, results from reciprocal grafting between wild-type and miR399-overexpressing plants led to the conclusion that PHO2 in roots can be suppressed by a shoot-to-root movement of mature miR399 (66, 100).”
A MicroRNA Superfamily Regulates Nucleotide Binding Site–Leucine-Rich Repeats and Other mRNAs[W][OA] (2012, background): “In some instances, the miRNAs or their precursors may move through plasmodesmata and different stages in the feedback system occur in adjacent cells or in separate roots and shoots (Bari et al., 2006; Pant et al., 2008).”
Origin, biogenesis, and activity of plant microRNAs. (2009, positive): “Consistent with this idea, Pant and colleagues have shown that following micrografting of miR-399-overexpressing scions (Pant et al., 2008), transcripts of the PHO2 gene were targeted by miR-399 in roots of wild-type rootstocks grown on phosphate-rich medium.”
Comprehending crystalline β-carotene accumulation by comparing engineered cell models and the natural carotenoid-rich system of citrus (2011, neutral): “miRNAs regulate a number of metabolic and developmental processes including root, shoot, and leaf growth, stomatal development, organ polarity, nutrient uptake and allocation, senescence, and abiotic stress response (Chiou, 2007; Kutter et al., 2007; Pant et al., 2008; Liang et al., 2010; Meng et al”
Plant microRNAs: new players in functional genomics (2013, positive): “Transcriptional regulation upon nutrient limitation in plants via miRNA-mediated gene expression adjustment has been reported for several element deficiencies, such as phosphate (Pant et al. 2008; Hsieh et al. 2009), sulfate (Rausch et al.”
Role of miRNAs and siRNAs in biotic and abiotic stress responses of plants (2011, neutral): “miR399 has been isolated from phloem, and its abundance in phloem increases upon phosphate starvation [81, 82].”
Uncovering Small RNA-Mediated Responses to Phosphate Deficiency in Arabidopsis by Deep Sequencing1[W][OA] (2009, background): “Notably, recent results from reciprocal grafting suggest that miR399 may serve as a long-distance signal from shoots to suppress PHO2 expression in roots as a way of communication between the Pi status of shoots and the Pi transport activity of roots (Lin et al., 2008; Pant et al., 2008).”