title: Light-mediated modulation of helix angle and rate of seminal root tip movement determines root morphology of young rice seedlings.
abstract: Seminal root growth is one of the factors to determine rice seedling establishment. Our previous reports showed light can induce Z-type wavy root and coiling root morphology in several rice (Oryza sativa L.) varieties, and the regulated Z-type and unregulated coil seminal roots were resulted by different circumnutational trajectories. Moreover, the light-induced seminal root waving was conducted by an NO-dependent signaling pathway. In order to further reveal the difference of root tip movement between straight and wavy seminal roots; here, the root tip movement trajectories of Tainung 67 variety (TNG67; presented straight root in light conditions) and Taichung Native 1 (TCN1; presented Z-type wavy root in light) were recorded and analyzed in both white light and dark (dim far-red light was applied in dark for taking time-lapse photography) conditions. The results showed the root tip movement of both rice varieties in low intensity of dim far-red light conditions were followed the circumnutation path. However, the stimuli of high intensity of white light would increase the root helix angle in TCN1 seedlings but not in TNG67. In addition, slowing down the rate of root helix was induced by white light treatment in TCN1 but not in TNG67 seedlings. In conclusion, changes of TCN1 rice seminal root morphology from straight to wavy type stimulated by light was resulted by both helix angle increasing and circumnutation rate slowing of root tip movement.
authors.affiliation: a Department of Agronomy , National Taiwan University , Taipei , Taiwan.
authors.forename: Hsiang-Wen
authors.initials: HW
authors.lastname: Chen
authors.affiliation: a Department of Agronomy , National Taiwan University , Taipei , Taiwan.
authors.forename: Ko-Hsuan
authors.initials: KH
authors.lastname: Shao
authors.affiliation: a Department of Agronomy , National Taiwan University , Taipei , Taiwan.
authors.forename: Shu-Jen
authors.initials: SJ
authors.lastname: Wang
mesh_terms: D008027:Light; D055537:Light Signal Transduction; D012275:Oryza / Q000033:anatomy & histology / Q000254:growth & development* / Q000528:radiation effects; D018517:Plant Roots / Q000033:anatomy & histology / Q000254:growth & development / Q000528:radiation effects; D036226:Seedlings / Q000033:anatomy & histology / Q000254:growth & development / Q000528:radiation effects; D059008:Time-Lapse Imaging
keywords: Circumnutation; oryza sativa, photomorphogenesis, seminal root, wavy root
references.citation: Annu Rev Plant Biol. 2013;64:403-27
references.pmid: 23373700
references.citation: Physiol Plant. 2009 Nov;137(3):289-97
references.pmid: 19744160
references.citation: Am J Bot. 2013 Jan;100(1):4-13
references.pmid: 23243099
references.citation: Plant Sci. 2014 May;221-222:42-7
references.pmid: 24656334
references.citation: Curr Top Dev Biol. 2010;91:29-66
references.pmid: 20705178
references.citation: Protoplasma. 2015 Sep;252(5):1291-304
references.pmid: 25619895
references.citation: Annu Rev Plant Physiol Plant Mol Biol. 1996 Jun;47:215-243
references.pmid: 15012288
references.citation: Photochem Photobiol. 2007 Jan-Feb;83(1):131-8
references.pmid: 17029495
references.citation: Science. 1995 May 5;268(5211):675-80
references.pmid: 7732376
references.citation: Plant Cell Rep. 2011 Sep;30(9):1747-58
references.pmid: 21573806
references.citation: Plant Cell. 2005 Dec;17(12):3311-25
references.pmid: 16278346