한빛사 논문
Abstract
Keunhwa Kima, Jieun Shina, Sang-Hee Leeb, Hee-Seok Kweonb, Julin N. Maloofc, and Giltsu Choia,1
aDepartment of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea;
bDivision of Electronmicroscopic Research, Korea Basic Science Institute, Daejeon 305-333, Korea; and
cDepartment of Plant Biology, University of California, Davis, CA 95616
Edited by Winslow R. Briggs, Carnegie Institution of Washington, Stanford, CA, and approved December 21, 2010 (received for review July 28, 2010)
Abstract
Phytochromes are red and far-red light photoreceptors that regulate various aspects of plant development. One of the less-understood roles of phytochromes is the inhibition of hypocotyl negative gravitropism, which refers to the loss of hypocotyl gravitropism and resulting random growth direction in red or far-red light. This light response allows seedlings to curve toward blue light after emergence from the soil and enhances seedling establishment in the presence of mulch. Phytochromes inhibit hypocotyl negative gravitropism by inhibiting four phytochrome-interacting factors (PIF1, PIF3, PIF4, PIF5), as shown by hypocotyl agravitropism of dark-grown pif1 pif3 pif4 pif5 quadruple mutants. We show that phytochromes inhibit negative gravitropism by converting starch-filled gravity-sensing endodermal amyloplasts to other plastids with chloroplastic or etioplastic features in red or far-red light, whereas PIFs promote negative gravitropism by inhibiting the conversion of endodermal amyloplasts to etioplasts in the dark. By analyzing transgenic plants expressing PIF1 with an endodermis-specific SCARECROW promoter, we further show that endodermal PIF1 is sufficient to inhibit the conversion of endodermal amyloplasts to etioplasts and hypocotyl negative gravitropism of the pif quadruple mutant in the dark. Although the functions of phytochromes in gravitropism and chloroplast development are normally considered distinct, our results indicate that these two functions are closely related.
Footnotes
1To whom correspondence should be addressed.
Author contributions: K.K. and G.C. designed research; K.K., J.S., S.-H.L., and H.-S.K. performed research; K.K., J.S., J.N.M., and G.C. analyzed data; and K.K., J.N.M., and G.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at
www.pnas.org/lookup/suppl/doi:10.1073/pnas.1011066108/-/DCSupplemental.
논문정보
관련 링크
연구자 키워드
관련분야 연구자보기
소속기관 논문보기
관련분야 논문보기
해당논문 저자보기