TLDR High levels of auxin increase root hair growth by activating RSL2 and producing ROS, while high phosphate levels hinder growth by repressing RSL2.
The study explored the effects of high auxin and phosphate (Pi) levels on root hair growth in Arabidopsis thaliana, focusing on the role of transcription factors RSL4 and RSL2 and reactive oxygen species (ROS) homeostasis. It was found that high Pi levels repress RSL4 and RSL2 expression and root hair growth, while high auxin levels promote growth by activating RSL2 expression and ROS production. The study also demonstrated that inhibiting ROS production blocked the growth-promoting effects of auxin, indicating the importance of ROS homeostasis in this process. Overexpression of RSL4 or ARF5 could partially counteract the growth repression caused by high Pi. The results suggest a complex interplay between auxin, Pi, and ROS homeostasis, with RSL2 playing a central role in mediating root hair growth under these conditions.
January 2018 in “bioRxiv (Cold Spring Harbor Laboratory)” Auxin helps root hairs grow in high phosphate by affecting ROS and involving RSL2 and RSL4.
April 2024 in “bioRxiv (Cold Spring Harbor Laboratory)” A gene network led by RSL4 is crucial for early root hair growth in response to cold in Arabidopsis thaliana.
14 citations
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March 2022 in “Plant Cell & Environment” The study explored the role of the novel calmodulin-interacting protein AtRXR3 in repressing root hair elongation in Arabidopsis under phosphorus deficiency. AtRXR3, part of the DUF506 gene family, inhibited root hair growth by interacting with RSL4 and cytosolic calmodulins, differing from AtRXR1's mechanism involving a small GTPase. RXR3 expression was upregulated in response to phosphorus deprivation and auxin, independent of PHR1 and PHL1 transcription factors. Overexpression of RXR3 resulted in shorter root hairs, while mutants had longer root hairs and increased phosphorus content, indicating RXR3's role as a growth repressor affecting phosphorus uptake. The study involved measurements from 10 seedlings per genotype and confirmed RXR3's interaction with calmodulins, suggesting its involvement in CaM-mediated pathways and highlighting its distinct function from RXR1 in the phosphorus limitation-induced root hair growth regulatory network.
75 citations
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July 2016 in “New phytologist” The protein RSL4 is crucial for making root hairs longer by controlling genes related to cell growth.
March 2021 in “Research Square (Research Square)” The SbbHLH85 protein helps sweet sorghum grow more root hairs but makes the plant more sensitive to salt.
