Knockdown of MicroRNA160a/b by STTM leads to root architecture changes via auxin signaling in Solanum tuberosum

The root phenotype is an important aspect of plant architecture and plays a critical role in plant facilitation of the extraction of water and nutrition from the soil. MicroRNAs (miRNAs) are classes of small RNAs with important roles in regulating endogenous gene expression at the post-transcriptional level that function in a range of plant development processes and in the response to abiotic stresses. However, little is known concerning the molecular mechanism of miRNAs in regulating the generation and development of plant root architecture. Herein, we demonstrated that potato miR160a/b acted as a critical regulator and affected plant root architecture by targeting the mRNA of StARF10 and StARF16 for cleavage. The miR160a/b precursor was cloned from potato. Quantitative PCR assays showed that the expression levels of miR160 and its targets were down- or up-regulated with the development of potato roots, respectively. Moreover, transgenic lines with suppressed stu-miR160 expression were established with the short tandem targets mimic (STTM), and the results showed that the ectopic expression of miR160a/b altered the levels of auxin and the expression of auxin signaling-related genes and caused drastic change in root architecture compared with that in control plants. Suppressing the expression of miR160 led to a severe reduction in root length, an increase in the number of lateral roots, and a decrease in fresh root weight in potato. Collectively, our data established a key role of miR160 in modulating plant root architecture in potato.