Open AccessAbiotic stress modulates root patterning via ABA-regulated microRNA expression in the endodermis initials
Author(s) -
Daria Bloch,
Mallikarjuna Rao Puli,
Assaf Mosquna,
Shaul Yalovsky
Publication year - 2019
Publication title -
development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.754
H-Index - 325
eISSN - 1477-9129
pISSN - 0950-1991
DOI - 10.1242/dev.177097
Subject(s) - biology , microbiology and biotechnology , endodermis , meristem , arabidopsis , abscisic acid , mutant , auxin , xylem , homeobox , repressor , regulation of gene expression , transcription factor , botany , genetics , gene
Patterning of the root xylem into protoxylem (PX) and metaxylem is regulated by auxin-cytokinin signaling and microRNA miR165a/166b-mediated suppression of genes encoding Class III HOMEODOMAIN LEU-ZIPPER (HD-ZIPIII) proteins. We found that in Arabidopsis osmotic stress via core abscisic acid (ABA) signaling in meristematic endodermal cells induces differentiation of PX in radial and longitudinal axes in association with increased VND7 expression. Similarly, in tomato ABA enhanced PX differentiation in the longitudinally and radially, indicating an evolutionarily conserved mechanism. ABA increased expression of miR165a/166b and reduced expression of miR165a/166b repressor ARGONAOUTE10/ZWILLE, resulting in reduced levels of all five HD-ZIPIII RNAs. ABA treatments failed to induce additional PX files in a miR165a/166b-resistant PHB mutant, phb1-d, and in scr and shr mutants, in which miR165a/166b expression are strongly reduced. Thus, ABA regulates xylem patterning and maturation via miR165a/166b-regulated expression of HD-ZIPIII mRNAs and associated VND7 levels. In lateral root initials, ABA induced increase in miR165a levels in endodermal precursors and inhibited their reduction in the future quiescent center specifically at pre-emergence stage. Hence, ABA-induced inhibition of lateral root is associated with reduced HD-ZIPIII levels.