Developmental changes in barley microRNA expression profiles coupled with miRNA target analysis.

Area of Science:

• Plant molecular biology
• Genomics and transcriptomics
• Agricultural science

Background:

• MicroRNAs (miRNAs) are small, single-stranded RNAs essential for regulating gene expression in plants, influencing development and environmental responses.
• Understanding miRNA dynamics during different developmental stages is crucial for comprehending plant growth control.

Purpose of the Study:

• To profile microRNA expression across five distinct barley developmental stages.
• To identify and characterize specific microRNA variants (izomiRs) and their expression patterns during barley development.
• To investigate the targets of identified microRNAs, particularly focusing on transcription factor families.

Main Methods:

• Microtranscriptome sequencing of barley at five developmental stages.
• Bioinformatic analysis to identify and quantify microRNA and izomiR expression.
• Degradome sequencing to experimentally validate microRNA-target interactions.

Main Results:

• Distinct expression profiles for several microRNAs (miR168-3p, miR1432-5p, miR156-5p) were observed during barley development.
• Two miR156-5p izomiRs, 5'U-miR156-5p and 5'UU-miR156-5p, exhibited differential expression patterns correlating with plant age.
• Only 5'U-miR156-5p was found to target messenger RNAs (mRNAs) of Squamosa Promoter Binding Protein-Like (SPL) transcription factors.

Conclusions:

• Barley development involves dynamic regulation by specific microRNAs and their variants.
• The miR156-5p family, particularly the 5'U-miR156-5p izomiR, plays a role in regulating SPL transcription factors during plant growth.
• This study provides a comprehensive resource for barley microRNA expression profiles and target interactions across developmental stages.