title: miR393-Mediated Auxin Signaling Regulation is Involved in Root Elongation Inhibition in Response to Toxic Aluminum Stress in Barley.
abstract: High-throughput small RNA sequencing has identified several potential aluminum (Al)-responsive microRNAs (miRNAs); however, their regulatory role remains unknown. Here, we identified two miR393 family members in barley, and confirmed two target genes-HvTIR1 and HvAFB-through a modified form of 5'-RACE (rapid amplification of cDNA ends) as well as degradome data analysis. Furthermore, we investigated the biological function of the miR393/target module in root development and its Al stress response. The investigation showed that miR393 affected root growth and adventitious root number by altering auxin sensitivity. Al3+ exposure suppressed miR393 expression in root apex, while overexpression of miR393 counteracted Al-induced inhibition of root elongation and alleviated reactive oxygen species (ROS)-induced cell death. Target mimic (MIM393)-mediated inhibition of miR393's activity enhanced root sensitivity to Al toxicity. We also confirmed that auxin enhanced Al-induced root growth inhibition in barley via application of exogenous 1-naphthaleneacetic acid (NAA), and the expression of auxin-responsive genes in the root apex was induced upon Al treatment. Overexpression of miR393 attenuated the effect of exogenous NAA on Al-induced root growth inhibition, and down-regulated the expression of auxin-responsive genes under Al stress, implying that miR393 regulates root sensitivity to Al through the alteration of auxin signaling output in barley. Therefore, these data indicate that miR393 acts as an integrator of environmental cues in auxin signaling, and suggest a new strategy to improve plant resistance to Al toxicity.
authors.affiliation: Laboratory of Plant-Animal Interactions, College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, China.|Yunnan Forestry Technological College, Kunming, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Bai
authors.affiliation: Institute of Genetic and Regenerative Biology, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Hongwu
authors.initials: H
authors.lastname: Bian
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China.
authors.forename: Zhanghui
authors.initials: Z
authors.lastname: Zeng
authors.affiliation: Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics and Regenerative Biology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
authors.forename: Ning
authors.initials: N
authors.lastname: Hou
authors.affiliation: Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Shi
authors.affiliation: College of Biological Sciences and Technology, Beijing Forestry University, Beijing, People's Republic of China.
authors.forename: Junhui
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Science of Pesticides, School of Resources and Environment, Anhui Agricultural University, Hefei, China.
authors.forename: Muyuan
authors.initials: M
authors.lastname: Zhu
authors.affiliation: Development and Utilization Key Laboratory of Northeast Plant Materials, School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Han
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D001467:Hordeum / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
chemical_list: D007210:Indoleacetic Acids; D035683:MicroRNAs; D010940:Plant Proteins; D000535:Aluminum
keywords: Al resistance; Auxin receptor; Auxin signaling; Barley; Root growth; miRNA393