A miR169 isoform regulates specific NF‐YA targets and root architecture in Arabidopsis

Abstract

Summary In plants, roots are essential for water and nutrient acquisition. MicroRNAs (miRNAs) regulate their target mRNAs by transcript cleavage and/or inhibition of protein translation and are known as major post‐transcriptional regulators of various developmental pathways and stress responses. In Arabidopsis thaliana, four isoforms of miR169 are encoded by 14 different genes and target diverse mRNAs, encoding subunits A of the NF‐Y transcription factor complex. These miRNA isoforms and their targets have previously been linked to nutrient signalling in plants. By using mimicry constructs against different isoforms of miR169 and miR‐resistant versions of NF‐YA genes we analysed the role of specific miR169 isoforms in root growth and branching. We identified a regulatory node involving the particular miR169defg isoform and NF‐YA2 and NF‐YA10 genes that acts in the control of primary root growth. The specific expression of MIM169defg constructs altered specific cell type numbers and dimensions in the root meristem. Preventing miR169defg‐regulation of NF‐YA2 indirectly affected laterial root initiation. We also showed that the miR169defg isoform affects NF‐YA2 transcripts both at mRNA stability and translation levels. We propose that a specific miR169 isoform and the NF‐YA2 target control root architecture in Arabidopsis.

MtNF-YA1, A Central Transcriptional Regulator of Symbiotic Nodule Development, Is Also a Determinant of Medicago truncatula Susceptibility toward a Root Pathogen

“…In Arabidopsis thaliana , overexpression of the closest homolog of MtNF-YA1, AtNF-YA2 leads to a significant increase in LR primordia density (Sorin et al, 2014) and the authors propose that AtNF-YA2 controls root architecture. Furthermore Laporte et al (2014) reported that MtNF-YA1 is also expressed transiently in LR primordia during LR initiation suggesting that this gene may also control LR growth in M. truncatula .…”

“…This view is supported by the resistance triggered by miR169q overexpression in F83005.5 which is stronger than the one obtained via RNA interference. miR169 is encoded by a large gene family in plants (14 genes in Arabidopsis leading to four different mature miR169s ) and targets specifically the product of NF-YA genes with a certain degree of specificity (Sorin et al, 2014). It is thus likely that other NF-YA subunits such as MtNF-YA2 for example that is expressed in roots at a much higher level than MtNF-YA1 are targeted by the miR169q in M. truncatula and play overlapping functions with MtNF-YA1 in the susceptibility to A. euteiches .…”

Deep Sequencing of the Medicago truncatula Root Transcriptome Reveals a Massive and Early Interaction between Nodulation Factor and Ethylene Signals

“…Root hair curling and infection are also associated with changes in the microtubule cytoskeleton, and b-tubulins, which are cytoskeletal proteins, have been shown to be up-regulated in root hairs (Timmers, 2008;Breakspear et al, 2014; Perrine-Walker et al, 2014). We Sorin et al (2014). f De Smet et al (2008).…”

A Wheat CCAAT Box-Binding Transcription Factor Increases the Grain Yield of Wheat with Less Fertilizer Input

“…It has been demonstrated that miR169/NFYA modules are important regulators of primary and lateral root development. For instance, expressing a miR169-resistant version of AtNFYA2 in Arabidopsis indirectly increased lateral root initiation and lateral root density but did not affect primary root growth (Sorin et al, 2014). However, the molecular mechanisms through which miR169/NFYA modules regulate root development are still not understood well.…”