Singh Archita, Singh Sharmila, Panigrahi Kishore C S, Reski Ralf, Sarkar Ananda K
National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India.
Plant Cell Rep. 2014 Jun;33(6):945-53. doi: 10.1007/s00299-014-1573-z. Epub 2014 Feb 7.
Overexpression of miR166/165 down-regulates target HD - ZIP IIIs and promotes root growth by enhancing cell division and meristematic activity, whereas overexpression of HD - ZIP IIIs inhibits root growth in Arabidopsis thaliana. Post-embryonic growth of higher plants is maintained by active meristems harbouring undifferentiated cells. Shoot and root apical meristems (SAM and RAM) utilize both similar and distinct signalling mechanisms for their maintenance in Arabidopsis thaliana. An important regulatory role in this context has the interaction of microRNAs with their target mRNAs, mostly encoding transcription factors. One class of microRNA166/165 (miR166/165) has been implicated in the maintenance of SAM and vascular patterning. Here, we show that miR166/165 plays an important role in root growth also by negatively regulating its target transcripts, HD-ZIP IIIs, in the RAM. While overexpression of miR166 promotes RAM activity, overexpression of its targets reduces RAM activity. These results reveal a conserved role of miR166/165 in the maintenance of SAM and RAM activity in A. thaliana.
miR166/165的过表达下调靶标HD - ZIP IIIs，并通过增强细胞分裂和分生组织活性促进根生长，而HD - ZIP IIIs的过表达则抑制拟南芥根的生长。高等植物胚后生长由含有未分化细胞的活跃分生组织维持。在拟南芥中，茎尖和根尖分生组织（SAM和RAM）利用相似和不同的信号传导机制来维持自身。在这种情况下，微小RNA与其靶标mRNA（大多编码转录因子）的相互作用起着重要的调节作用。一类微小RNA166/165（miR166/165）与SAM维持和维管模式形成有关。在这里，我们表明miR166/165通过在RAM中负调控其靶标转录本HD - ZIP IIIs，在根生长中也发挥重要作用。虽然miR166过表达促进RAM活性，但其靶标的过表达降低RAM活性。这些结果揭示了miR166/165在拟南芥SAM和RAM活性维持中的保守作用。
