SHORT ROOT and SCARECROW Promote Root Stem SHORT-ROOT and SCARECROW Promote Root Stem Cell Activity by Suppressing Stress Signaling Cell Activity by Suppressing Stress Signaling y y pp g g g - PDF Document

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  1. SHORT ROOT and SCARECROW Promote Root Stem SHORT-ROOT and SCARECROW Promote Root Stem Cell Activity by Suppressing Stress Signaling Cell Activity by Suppressing Stress Signaling y y pp g g g Hongchang Cui Hongchang Cui Department of Biological Science Florida State University Department of Biological Science, Florida State University, Tallahassee FL 32306 Email: hcui@bio fsu edu Tallahassee, FL 32306 Email: hcui@bio.fsu.edu Observations Observations Introduction Introduction  SCR and SHR are essential for root growth  SCR and SHR are essential for root growth  U lik  Unlike animals, plants maintain two populations of stem cells after populations of stem cells after embryogenesis embryogenesis − one at the shoot tip, the other at the root tip − and continuous activity of these stem cells continuous activity of these stem cells t ib t t th i d t contributes to the indeterminate growth of plants growth of plants i l l t i t i t scr scr WT WT shr shr ABA ABA (M) (M) WT WT shr shr scr scr one at the shoot tip p - i t +  Stem cell activity is inhibited by stress.  Stem cell activity is inhibited by stress. Plants are immotile and to survive an Plants are immotile and, to survive an ever-changing environment, they must g g keep a balance between growth and keep a balance between growth and t stress responses  h  shr and scr mutants are hypersensitive to ABA, a stress-associated plant hormone d t t h iti t , y  The ABA-insensitive aba2 mutant alleviates  The ABA-insensitive aba2 mutant alleviates the short root defects of shr and scr the short root defects of shr and scr 15±2 40±2 44±2 aba2 scr scr aba2  SCARECROW (SCR)  SCARECROW (SCR) and SHORT- ROOT (SHR) are important regulators ROOT (SHR) are important regulators of stem cell renewal in root but how of stem cell renewal in root, but how h i i they maintain stem cell activity is y unknown unknown d SHORT 44±3 34±4 12±2 ll i i y i scr scr scr aba2 scr aba2 aba2 aba2 ) mm (m gth eng ot le Roo R R Results Results lt  W f  We found that SCR and SHR repress stress response, and the short-root stress response, and the short root defects of scr and shr mutants were defects of scr and shr mutants were alleviated by mutations in genes that y are involved in stress response and are involved in stress response and i li signaling d th t SCR d SHR g  The scr aba2 and shr aba2 mutants have a  The scr aba2 and shr aba2 mutants have a greater number of stem cells greater number of stem cells scr aba2 scr aba2 F t Future directions di ti  To elucidate the molecular mechanism  To elucidate the molecular mechanism b hi h SCR by which SCR promotes root stem cell activity under stresses activity under stresses 15±2 15±2 40±2 40±2 44±2 44±2 t t t ll shr aba2 shr shr aba2 aba2  To identify additional factors that  To identify additional factors that di t t coordinate root growth and stress responses responses th d t 44±3 44±3 34±4 34±4 12±2 12±2