title: Illumina microRNA profiles reveal the involvement of miR397a in Citrus adaptation to long-term boron toxicity via modulating secondary cell-wall biosynthesis.
abstract: The mechanisms underlying tolerance to B-toxicity in plants are still controversial. Our previous studies indicated that B-toxicity is mainly limited to leaves in Citrus and that alternations of cell-wall structure in vascular bundles are involved in tolerance to B-toxicity. Here, miRNAs and their expression patterns were first identified in B-treated Citrus sinensis (tolerant) and C. grandis (intolerant) leaves via high-throughput sequencing. Candidate miRNAs were then verified with molecular and anatomical approaches. The results showed that 51 miRNAs in C. grandis and 20 miRNAs in C. sinensis were differentially expressed after B-toxic treatment. MiR395a and miR397a were the most significantly up-regulated miRNAs in B-toxic C. grandis leaves, but both were down-regulated in B-toxic C. sinensis leaves. Four auxin response factor genes and two laccase (LAC) genes were confirmed through 5'-RACE to be real targets of miR160a and miR397a, respectively. Up-regulation of LAC4 resulted in secondary deposition of cell-wall polysaccharides in vessel elements of C. sinensis, whereas down-regulation of both LAC17 and LAC4, led to poorly developed vessel elements in C. grandis. Our findings demonstrated that miR397a plays a pivotal role in woody Citrus tolerance to B-toxicity by targeting LAC17 and LAC4, both of which are responsible for secondary cell-wall synthesis.
authors.affiliation: Institute of Plant Nutritional Physiology and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|Pomological Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China.|College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
authors.forename: Jing-Hao
authors.initials: JH
authors.lastname: Huang
authors.affiliation: Institute of Materia Medica, Fujian Academy of Medical Sciences, Fuzhou 350001, China.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Qi
authors.affiliation: Pomological Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China.
authors.forename: Shou-Xing
authors.initials: SX
authors.lastname: Wen
authors.affiliation: Institute of Plant Nutritional Physiology and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|College of Resource and Environmental Science, Fujian Agriculture and Forestry University,Fuzhou 350002, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Guo
authors.affiliation: Pomological Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013, China.
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Chen
authors.affiliation: Institute of Plant Nutritional Physiology and Molecular Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|College of Resource and Environmental Science, Fujian Agriculture and Forestry University,Fuzhou 350002, China.|Fujian Key Laboratory for Plant Molecular and Cell Biology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
authors.forename: Li-Song
authors.initials: LS
authors.lastname: Chen
mesh_terms: D000064:Acclimatization / Q000235:genetics; D000222:Adaptation, Physiological / Q000235:genetics*; D001895:Boron / Q000633:toxicity; D002473:Cell Wall / Q000235:genetics* / Q000378:metabolism; D002957:Citrus / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development
chemical_list: D035683:MicroRNAs; D001895:Boron