Plants (Feb 2020)

Alternative Polyadenylation and Salicylic Acid Modulate Root Responses to Low Nitrogen Availability

  • Carlos M. Conesa,
  • Angela Saez,
  • Sara Navarro-Neila,
  • Laura de Lorenzo,
  • Arthur G. Hunt,
  • Edgar B. Sepúlveda,
  • Roberto Baigorri,
  • Jose M. Garcia-Mina,
  • Angel M. Zamarreño,
  • Soledad Sacristán,
  • Juan C. del Pozo

DOI
https://doi.org/10.3390/plants9020251
Journal volume & issue
Vol. 9, no. 2
p. 251

Abstract

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Nitrogen (N) is probably the most important macronutrient and its scarcity limits plant growth, development and fitness. N starvation response has been largely studied by transcriptomic analyses, but little is known about the role of alternative polyadenylation (APA) in such response. In this work, we show that N starvation modifies poly(A) usage in a large number of transcripts, some of them mediated by FIP1, a component of the polyadenylation machinery. Interestingly, the number of mRNAs isoforms with poly(A) tags located in protein-coding regions or 5′-UTRs significantly increases in response to N starvation. The set of genes affected by APA in response to N deficiency is enriched in N-metabolism, oxidation-reduction processes, response to stresses, and hormone responses, among others. A hormone profile analysis shows that the levels of salicylic acid (SA), a phytohormone that reduces nitrate accumulation and root growth, increase significantly upon N starvation. Meta-analyses of APA-affected and fip1-2-deregulated genes indicate a connection between the nitrogen starvation response and salicylic acid (SA) signaling. Genetic analyses show that SA may be important for preventing the overgrowth of the root system in low N environments. This work provides new insights on how plants interconnect different pathways, such as defense-related hormonal signaling and the regulation of genomic information by APA, to fine-tune the response to low N availability.

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