Tall fescue (Festuca arundinacea Schreb.) is the predominant forage and cool-season turfgrass species grown widely in the world, but the low tiller density and size are the major factors limiting its turf performance and dry matter yield of forage.  

In this study, Prof. CHEN Liang and Associate Prof. HU Tao from Molecular Breeding of Turfgrass and Forage Grass Group, Wuhan Botanical Garden first identified the miRNAs controlling tiller development in two tall fescue genotypes contrasting for tillering production and two types of tissue samples at different tillering development stages using genome-wide small RNA profiling analysis. 

A total of 208 miRNAs were discovered, including 148 known miRNAs belonging to 70 families and 60 novel ones, which targeted 28927 potential target genes based on the previous full-length transcriptome data in tall fescue.  

18 miRNAs involved in 212 target genes were relative with tiller development process. Except for three miRNAs (osa-miR156a, zma-miR528a-3p and osa-miR444b.2), 15 miRNAs were novel regulators involved in tiller development in tall fescue plants. Most of the 212 target genes were assigned into five Kyoto Encyclopedia of Genes and Genomes pathways (“ubiquitin-mediated proteolysis”, "phagosome”, "fatty acid biosynthesis”, "oxidative phosphorylation”, and “biosynthesis of unsaturated fatty acids”). 

bdi-miR167e-3p targets two kinase proteins and osa-miR397a targets auxin response factor 5, indicating grass tillering may be relative to miRNA-kinases/ phytohormone signalling. 

Tillering related 18 miRNAs and their 212 target genes provide novel insights into the molecular mechanisms of miRNA-genes that mediate tiller development in cool-season turfgrass. 

Results were published in BMC Genomics online entitled “Genome-wide small RNA profiling reveals tiller development in tall fescue (Festuca arundinacea Schreb.)”. This work was supported by the National Natural Science Foundation of China.     

Tillering phenotypes of ‘Ch-3’, 'Ch-5’, Pre-tillering and Tillering plants (Image by WBG)