Abstract
MicroRNAs (miRNAs) play a critical role in gene regulation in plants. Several members of the pentatricopeptide repeat (PPR) family have been identified as predicted targets of Ahyp-miR0005, a miRNA specific to amaranth. PPR proteins are essential for mitochondrial and chloroplast biogenesis, as well as plastid-to-nucleus communication, processes fundamental for retrograde signaling between the plastid and nucleus (RSBPN). In this study, we identified the target of Ahyp-miR0005 and its association with the PPR protein family across Amaranthus hypochondriacus, Arabidopsis thaliana, Nicotiana tabacum, and Solanum lycopersicum. Cleavage inhibition by Ahyp-miR0005 was predicted, and the distribution of miRNA binding sites per target gene was analyzed, including their localization within coding PPR domains. Among the main Ahyp-miR0005 target genes, we identified GUN-1, ABO5, and MORF1. Interaction network analysis revealed that different target genes are co-expressed in response to the same stimulus. Gene expression profiling with the Arabidopsis eFP Browser revealed substantial transcriptional changes in predicted targets under six abiotic stress conditions. We further show that abiotic stresses alter the expression of Ahyp-miR0005 amaranth target genes. We anticipate that the expression of Ahyp-miR0005 in non-amaranth plants could replicate the reorganization and coordination of gene expression through RSBPN, thereby improving plant tolerance to various abiotic stresses.