Edinburgh, Scotland, United Kingdom - TAIR
Edinburgh, Scotland, United Kingdom - TAIR
Edinburgh, Scotland, United Kingdom - TAIR
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Tissue patterning and growth coordinated by<br />
a mobile microRNA and SHORT ROOT in the<br />
root<br />
One main interest in developmental biology is to understand the positional<br />
information for tissue patterning in developing organs. In plants, regulation of<br />
tissue patterning has to be coordinated with cell division to assist post embryonic<br />
growth.<br />
Here, we present a novel crosstalk mechanism mediated by SHORT ROOT<br />
(SHR) that regulates root tissue patterning and growth. SHR proteins, produced<br />
in the xylem and procambium of Arabidopsis roots, move to the rest of vascular<br />
cylinder cells, endodermis, and QC. In the endodermis and QC, SHR directly<br />
activates SCARECROW (SCR) and together forms a complex. SHR/SCR<br />
complex regulates not only the development of ground tissues and QC but also<br />
the cell proliferation and patterning in the vascular cylinder. In the shr or scr<br />
mutants, fewer cell files form in the vascular cylinder and ectopic metaxylem<br />
develops in the place of the protoxylem. We found that SHR/SCR regulate these<br />
by directly activating a subset of miR165/166 genes in the endodermis.<br />
MiR165/166 produced in the endodermis moves into the vascular cylinder and<br />
restricts mRNA domains of PHABULOSA (PHB) and other class III HD-ZIP<br />
transcription factors to the center of the vascular cylinder. In shr phb double<br />
mutant, the protoxylem and cell proliferation were recovered in the vascular<br />
cylinder. Furthermore, the root apical growth was also largely recovered without<br />
the recovery of QC, suggesting the contribution of PHB mediated cell<br />
proliferation in the vascular cylinder for apical root growth.<br />
This novel crosstalk mechanism provides new insight into the patterning and<br />
growth of developing organs.<br />
72<br />
C21<br />
Wednesday 17:15 - 17:30<br />
Development<br />
Jing Zhou1,2<br />
Jose Sebastian1<br />
Gustavo Acevedo1<br />
Philip Benfey3<br />
Annelie Carlsbecker4<br />
Yka Helariutta5<br />
Ji-Young Lee1,6<br />
1Boyce Thompson Institute<br />
for Plant Research<br />
Ithaca<br />
NY<br />
USA<br />
2Graduate Field of Plant<br />
Biology<br />
Cornell University<br />
Ithaca<br />
NY<br />
USA<br />
3Duke University<br />
Durham<br />
NC<br />
USA<br />
4Uppsala University,<br />
Uppsala<br />
Sweden<br />
5Helsinki University,<br />
Helsinki<br />
Finland<br />
6Department of Plant<br />
Biology<br />
Cornell University<br />
Ithaca<br />
NY<br />
USA
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