Identification and functional analysis of new conserved microRNAs and their targets in potato (Solanum tuberosum L.)

Abstract

MicroRNAs (miRNAs) are tiny, endogenous, nonprotein-coding, and functionally negative regulators of posttranscriptional gene regulation. Potato (Solanum tuberosum L.) is a starchy and tuberous crop that is also important for its potassium and vitamin contents. Though potato is the world's fourth largest food crop, its miRNAs and their targets have not been well studied. Here we report a comparative genomics approach that was applied to explore miRNAs and their targeted proteins in potato. A total of 120 new miRNAs from 110 families were identified and characterized from the expressed sequence tags. All 120 miRNAs were observed, along with stable stem-loop precursor structures, whose lengths ranged from 42 to 488 nt with an average of 132 nt. Mature miRNAs lengths ranged from 18 to 26 nt with an average of 21 nt. Later, 10 miRNAs were randomly selected for validation by reverse-transcription polymerase chain reaction. A total of 433 potential targets were predicted for these new 120 potato miRNAs. These targets were involved in regulation, metabolism, transcription factors, growth and development, and other physiological processes. These miRNAs and their targets will be useful to fine-tune potatoes for better food content and higher nutritional value as well biotic and abiotic stress resistance.