Light and shade in the photocontrol of Arabidopsis growth.
Plants have evolved sophisticated sensing mechanisms that operate through phytochromes, perceiving changes in the red:far-red ratio, which trigger morphological changes to avoid shade. The shade-avoidance response essentially redirects resources and growth potential from the leaf and storage organs into increased extension growth to optimize light capture by plants. Recent studies implicate ATHB-2, a homeodomain-leucine zipper transcription factor, as a regulator of shade-avoidance responses and establish a strong link between this factor and auxin signaling. The action of ATHB-2 is likely to generate changes in auxin distribution that produce distinct but coordinated effects on different cell types across the plant. Future studies should highlight how polarity of auxin transport is altered in response to light-quality changes.
Morelli
Giorgio
G
Unità di Nutrizione Sperimentale, Istituto Nazionale di Ricerca per gli Alimenti e la Nutrizione, Via Ardeatina 546, 00178 Rome, Italy.
Ruberti
Ida
I
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics; D001692:Biological Transport / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics; D003624:Darkness; D018398:Homeodomain Proteins; D008027:Light; D008954:Models, Biological; D010802:Phylogeny; D010834:Phytochrome / Q000378:metabolism*; D015398:Signal Transduction / Q000528:radiation effects
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C069386:HB-2 protein, Arabidopsis; D018398:Homeodomain Proteins; D010834:Phytochrome