Journal
PLANT PHYSIOLOGY
Volume 138, Issue 2, Pages 949-964Publisher
AMER SOC PLANT BIOLOGISTS
DOI: 10.1104/pp.105.061572
Keywords
-
Categories
Ask authors/readers for more resources
Light and auxin control many aspects of plant growth and development in an overlapping manner. We report here functional characterization of two closely related ABC (ATP-binding cassette) transporter genes, AtMDR1 and AtPGP1, in light and auxin responses. We showed that loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation, and abnormal expression of several light-responsive genes, including CAB3, RBCS, CHS, and PORA, under both darkness and far-red light conditions. In addition, we showed that the atmdr1-100 and atmdr1-100/atpgp1-100 mutants are defective in multiple aspects of root development, including increased root-growth sensitivity to 1-naphthalene acetic acid (1-NAA), and decreased sensitivity to naphthylphthalamic acid (NPA)-mediated inhibition of root elongation. Consistent with the proposed role of AtMDR1 in basipetal auxin transport, we found that expression of the auxin responsive DR5::GUS reporter gene in the central elongation zone is significantly reduced in the atmdr1-100 mutant roots treated with 1-NAA at the root tips, compared to similarly treated wildtype plants. Moreover, atmdr1-100, atpgp1-100, and their double mutants produced fewer lateral roots, in the presence or absence of 1-NAA or NPA. The atmdr1-100 and atmdr1-100/atpgp1-100 mutants also displayed enhanced root gravitropism. Genetic-epistasis analysis revealed that mutations in phyA largely suppress the randomized-hypocotyl growth and the short-hypocotyl phenotype of the atmdr1-100 mutants under far-red light, suggesting that phyA acts downstream of AtMDR1. Together, our results suggest that AtMDR1 and AtPGP1 regulate Arabidopsis ( Arabidopsis thaliana) photomorphogenesis and multiple aspects of root development by mediating polar auxin transport.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available