Key Laboratory of Horticultural Plant Biology, Ministry of Education; College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
Key Laboratory of Horticulture Science for Southern Mountains Regions, Ministry of Education; College of Horticulture and Landscape Architecture, Southwest University, Chongqing 400715, China.
Plant Cell Physiol. 2021 Oct 1;62(5):839-857. doi: 10.1093/pcp/pcab041.
miR156/157 plays multiple pivotal roles during plant growth and development. In this study, we identified 11 miR156- and 5 miR157-encoding loci from the genome of Petunia axillaris and Petunia inflata, designated as PaMIR0156/157s and PiMIR0156/157s, respectively. Real-time quantitative reverse transcription PCR (qRT-PCR) analysis indicated that PhmiR156/157 was expressed predominantly in cotyledons, germinating seeds, flower buds, young fruits and seedlings. PhmiR156/157 levels declined in shoot apical buds and leaves of petunia before flowering as the plant ages; moreover, the temporal expression patterns of most miR156/157-targeted PhSPLs were complementary to that of PhmiR156/157. Ectopic expression of PhMIR0157a in Arabidopsis and petunia resulted in delayed flowering, dwarf plant stature, increased branches and reduced organ size. However, PhMIR0156f-overexpressing Arabidopsis and petunia plants showed only delayed flowering. In addition, downregulation of PhmiR156/157 level by overexpressing STTM156/157 led to taller plants with less branches, longer internodes and precocious flowering. qRT-PCR analysis indicated that PhmiR156/157 modulates these traits mainly by downregulating their PhSPL targets and subsequently decreasing the expression of flowering regulatory genes. Our results demonstrate that the PhmiR156/157-PhSPL module has conserved but also divergent functions in growth and development, which will help us decipher the genetic basis for the improvement of flower transition, plant architecture and organ development in petunia.
miR156/157 在植物生长和发育过程中发挥着多种关键作用。在这项研究中，我们从矮牵牛和泡桐基因组中鉴定出 11 个 miR156-和 5 个 miR157-编码基因座，分别命名为 PaMIR0156/157s 和 PiMIR0156/157s。实时定量反转录 PCR（qRT-PCR）分析表明，PhmiR156/157 在子叶、萌发种子、花蕾、幼果和幼苗中表达量较高。随着植物年龄的增长，开花前矮牵牛茎尖芽和叶片中的 PhmiR156/157 水平下降；此外，大多数 miR156/157 靶向的 PhSPL 的时间表达模式与 PhmiR156/157 互补。拟南芥和矮牵牛中 PhMIR0157a 的异位表达导致开花延迟、植株矮小、分枝增加和器官大小减小。然而，PhMIR0156f 过表达的拟南芥和矮牵牛植物仅表现出开花延迟。此外，通过过表达 STTM156/157 下调 PhmiR156/157 水平导致植物更高、分枝更少、节间更长和提前开花。qRT-PCR 分析表明，PhmiR156/157 通过下调其 PhSPL 靶基因并随后降低开花调节基因的表达来调节这些性状。我们的结果表明，PhmiR156/157-PhSPL 模块在生长和发育过程中具有保守但也有差异的功能，这将有助于我们破译矮牵牛花转变、植物结构和器官发育的遗传基础。
