Addressing the Role of microRNAs in Reprogramming Leaf Growth during Drought Stress in Brachypodium distachyon

• Published in: Molecular plant 2013-03, Vol.6 (2), p.423-443
• Main Authors: Bertolini, Edoardo, Verelst, Wim, Horner, David Stephen, Gianfranceschi, Luca, Piccolo, Viviana, Inze, Dirk, Pe, Mario Enrico, Mica, Erica
• Format: Article
• Language: English
• Subjects: Base Sequence; Brachypodium; Brachypodium - cytology; Brachypodium - genetics; Brachypodium - growth & development; Brachypodium - physiology; Brachypodium distachyon; Cell Division - genetics; Conserved Sequence; drought; Droughts; Genetic Loci - genetics; Genomics; High-Throughput Nucleotide Sequencing; leaf development; MicroRNAs - genetics; miRNA; miRNAs; Molecular Sequence Data; Plant Leaves - genetics; Plant Leaves - growth & development; RNA, Plant - genetics; RNA基因; Stress, Physiological - genetics; 叶片生长; 寻址; 差异表达分析; 干旱胁迫; 表观遗传; 重新编程
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1093/mp/sss160

Plant responses to drought are regulated by complex genetic and epigenetic networks leading to rapid reprogramming of plant growth, miRNAs have been widely indicated as key players in the regulation of growth and development. The role of miRNAs in drought response was investigated in young leaves of Brachypodium dis- tachyon, a drought-tolerant monocot model species. Adopting an in vivo drought assay, shown to cause a dramatic reduction in leaf size, mostly due to reduced cell expansion, small RNA libraries were produced from proliferating and expanding leaf cells. Next-generation sequencing data were analyzed using an in-house bioinformatics pipeline allowing the identification of 66 annotated miRNA genes and 122 new high confidence predictions greatly expand- ing the number of known Brachypodium miRNAs. In addition, we identified four TAS3 loci and a large number of siRNA-producing loci that show characteristics suggesting that they may represent young miRNA genes. Most miR- NAs showed a high expression level, consistent with their involvement in early leaf development and cell identity. Proliferating and expanding leaf cells respond differently to drought treatment and differential expression analyses suggest novel evidence for an miRNA regulatory network controlling cell division in both normal and stressed condi-tions and demonstrate that drought trigger a genetic reprogramming of leaf growth in which miRNAs are deeply involved.