AUTHOR=Li Yuening , Wang Xianglong , Guo Qingxun , Zhang Xinsheng , Zhou Lianxia , Zhang Yang , Zhang Chunyu 

TITLE=Conservation and Diversity of miR166 Family Members From Highbush Blueberry (Vaccinium corymbosum) and Their Potential Functions in Abiotic Stress

JOURNAL=Frontiers in Genetics

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.919856

DOI=10.3389/fgene.2022.919856

ISSN=1664-8021

ABSTRACT=<p>MicroRNA166 (miR166) is highly conserved and has diverse functions across plant species. The highbush blueberry (<italic>Vaccinium corymbosum</italic>) genome is thought to harbor 10 miRNA166 loci (<italic>Vco-miR166</italic>), but the extent of their evolutionary conservation or functional diversification remains unknown. In this study, we identified six additional <italic>Vco-miR166</italic> loci based on conserved features of the miR166 family. Phylogenetic analyses showed that mature Vco-miR166s and their precursor cluster in several clades are evolutionary conserved with diverse species. The <italic>cis</italic>-regulatory elements in the <italic>Vco-miR166</italic> promoters indicated functions related to different phytohormones and defense responses. We also identified putative targets of vco-miR166s, which targeted the same gene families, suggesting the functional conservation and diversification of <italic>Vco-miR166</italic> family members. Furthermore, we examined the accumulation patterns of six mature Vco-miR166s in response to abiotic stresses by stem-loop reverse RT-qPCR, which revealed their upregulation under freezing, cold, and heat stress, while they were downregulated by drought compared to control growth conditions. However, <italic>Vco-miR166</italic> members showed different expression patterns when exposed to salt stress. These results showed that conserved Vco-miR166 family members display functional diversification but also coordinately influence plant responses to abiotic stress.</p>