AUTHOR=Xiao Liang , Man Liting , Yang Lina , Zhang Jinmei , Liu Baoyao , Quan Mingyang , Lu Wenjie , Fang Yuanyuan , Wang Dan , Du Qingzhang , Zhang Deqiang 

TITLE=Association Study and Mendelian Randomization Analysis Reveal Effects of the Genetic Interaction Between PtoMIR403b and PtoGT31B-1 on Wood Formation in Populus tomentosa

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.704941

DOI=10.3389/fpls.2021.704941

ISSN=1664-462X

ABSTRACT=<p>MicroRNAs (miRNAs), important posttranscriptional regulators of gene expression, play a crucial role in plant growth and development. A single miRNA can regulate numerous target genes, making the determination of its function and interaction with targets challenging. We identified PtomiR403b target to <italic>PtoGT31B-1</italic>, which encodes a galactosyltransferase responsible for the biosynthesis of cell wall polysaccharides. We performed an association study and epistasis and Mendelian randomization (MR) analyses to explore how the genetic interaction between <italic>PtoMIR403b</italic> and its target <italic>PtoGT31B-1</italic> underlies wood formation. Single nucleotide polymorphism (SNP)-based association studies identified 25 significant associations (<italic>P</italic> &lt; 0.01, <italic>Q</italic> &lt; 0.05), and <italic>PtoMIR403b</italic> and <italic>PtoGT31B-1</italic> were associated with five traits, suggesting a role for PtomiR403b and <italic>PtoGT31B-1</italic> in wood formation. Epistasis analysis identified 93 significant pairwise epistatic associations with 10 wood formation traits, and 37.89% of the SNP-SNP pairs indicated interactions between <italic>PtoMIR403b</italic> and <italic>PtoGT31B-1</italic>. We performed an MR analysis to demonstrate the causality of the relationships between SNPs in <italic>PtoMIR403b</italic> and wood property traits and that <italic>PtoMIR403b</italic> modulates wood formation by regulating expression of <italic>PtoGT31B-1</italic>. Therefore, our findings will facilitate dissection of the functions and interactions with miRNA-targets.</p>