AUTHOR=Zhang Li , Yao Lei , Zhang Ning , Yang Jiangwei , Zhu Xi , Tang Xun , Calderón-Urrea Alejandro , Si Huaijun 

TITLE=Lateral Root Development in Potato Is Mediated by Stu-mi164 Regulation of NAC Transcription Factor

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00383

DOI=10.3389/fpls.2018.00383

ISSN=1664-462X

ABSTRACT=<p>The NAC designation is derived from petunia (<italic>Petunia hybrida</italic>) gene <italic>NO APICAL MERISTEM</italic> (<italic><underline>N</underline>AM</italic>) and <italic>Arabidopsis</italic> genes <italic><underline>A</underline>TAF1/ATAF2</italic> and <italic>CUP-SHAPED COTYLEDON2</italic> (<italic><underline>C</underline>UC2</italic>), which belongs to the family of plant-specific transcription factors (TFs), and plays important role in plant development processes, such as response to biotic and abiotic stress, and hormone signaling. MicroRNAs (miRNAs) are a class of small, non-coding endogenous RNAs which play versatile and significant role in plant stress response and development via negatively affecting gene expression at a post-transcriptional level. Here, we showed that Stu-mi164 had a complementary sequence in the CDS sequence of potato NAC TFs, and that NAC expression exhibited significant differences under osmotic stress. We measured expression levels of the Stu-mi164 target gene <italic>StNAC262</italic> between control and PEG-treated plants using real-time PCR, and the results demonstrated that they had inverse relationship. We suggested that Stu-miR164 might drive overexpression of <italic>NAC</italic> gene under osmotic stress in potato. To confirm the regulation of NAC TFs by Stu-mi164, we developed transgenic plants, using <italic>Agrobacterium tumefaciens</italic>–mediated transformation, of the potato cultivars “Gannongshu 2” and “Kexin 3” overexpressing the Stu-mi164 or the TF <italic>StNAC262</italic>. Real-time PCR analysis of transgenic potato plants under osmotic (PEG) stress, showed that potato plants overexpressing Stu-mi164 had reduced expression of <italic>StNAC262</italic> and their osmotic resistance decreased. Furthermore, these plants had low number of lateral roots although the same length as the control. Our findings support the regulatory role of Stu-miRNAs in controlling plant response to osmotic stress via <italic>StNAC262</italic>.</p>