Cell/Development/Systems

Abstract

C-5-3 - Nitrogen-dependent modulation of lateral root development and root gravitropism through the CLAVATA signaling pathway

Sunday, July 15
1:43 PM - 2:03 PM

Plant root system architecture (RSA) changes in response to nutrient availability and actions of plant hormones and morphogen peptides. In Arabidopsis thaliana, nitrogen (N) starvation induces expression of CLAVATA3/ESR-related 3 (CLE3) peptides, which bind to the CLAVATA1 (CLV1) leucine-rich repeat receptor-like kinase to repress the emergence of lateral roots, an RSA modulation mechanism which may serve to impede root growth into nutrient poor environments. Transcriptome analysis to determine specific downstream components of the CLE3-CLV1 pathway revealed one potential candidate, PHOSPHOLIPID BINDING PROTEIN 1 (PLBP1). The Arabidopsis plbp1 mutant exhibited a moderate increase in lateral root density as well as severely agravitropic primary roots. Root gravitropic response, however, can be strengthened by application of ammonium independent of PLBP1 function, suggesting a complex role of N- and CLE3-derived signals influencing the root phenotypes. Additionally, the plbp1 mutant displayed aberrant auxin signaling and transport phenotypes, indicating its relevance to the observed weakening in gravitropic responses. Analysis of DR5:GFP expression in the wild-type and plbp1 backgrounds showed plbp1 mutants having significantly lower auxin accumulation in the root tip.  In contrast, the expression of PIN3-GFP translational fusion showed the auxin efflux transporter overexpressed and localized to a greater area in the root tip in the plbp1 mutant relative to the wild type. These results implicate PLBP1 as a regulatory component necessary for gravity-induced changes in auxin flux in the root tip. Combined with the established role of CLE3-CLV1 signaling in lateral root emergence, the role of PLBP1 in root gravitropism suggests this single morphogen peptide signaling pathway modulates these two RSA phenotypes in an opposite manner.


 

Co-Authors

Hideki Takahashi – Michigan State University

Katerina S. Lay

Graduate Student
Michigan State University

Presentation(s):

Send Email for Katerina Lay


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C-5-3 - Nitrogen-dependent modulation of lateral root development and root gravitropism through the CLAVATA signaling pathway



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