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Summary Root hair (RH) cells can elongate to several hundred times their initial size, and are an ideal model system for investigating cell size control. Their development is influenced by both endogenous and external signals, which are combined to form an integrative response. Surprisingly, a low‐temperature condition of 10°C causes increased RH growth inArabidopsisand in several monocots, even when the development of the rest of the plant is halted.Previously, we demonstrated a strong correlation between RH growth response and a significant decrease in nutrient availability in the growth medium under low‐temperature conditions. However, the molecular basis responsible for receiving and transmitting signals related to the availability of nutrients in the soil, and their relation to plant development, remain largely unknown.We have discovered two antagonic gene regulatory networks (GRNs) controlling RH early transcriptome responses to low temperature. One GNR enhances RH growth and it is commanded by the transcription factors (TFs)ROOT HAIR DEFECTIVE 6(RHD6),HAIR DEFECTIVE 6‐LIKE 2 and 4(RSL2‐RSL4) and a member of the homeodomain leucine zipper (HD‐Zip I) group I 16 (AtHB16). On the other hand, a second GRN was identified as a negative regulator of RH growth at low temperature and it is composed by the trihelix TFGT2‐LIKE1(GTL1) and the associated DF1, a previously unidentified MYB‐like TF (AT2G01060) and several members of HD‐Zip I group (AtHB3, AtHB13, AtHB20, AtHB23).Functional analysis of both GRNs highlights a complex regulation of RH growth response to low temperature, and more importantly, these discoveries enhance our comprehension of how plants synchronize RH growth in response to variations in temperature at the cellular level.
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A conserved gene regulatory network controls root epidermal cell patterning in superrosid species
Summary In superrosid species, root epidermal cells differentiate into root hair cells and nonhair cells. In some superrosids, the root hair cells and nonhair cells are distributed randomly (Type I pattern), and in others, they are arranged in a position‐dependent manner (Type III pattern). The model plant Arabidopsis (Arabidopsis thaliana) adopts the Type III pattern, and the gene regulatory network (GRN) that controls this pattern has been defined. However, it is unclear whether the Type III pattern in other species is controlled by a similar GRN as in Arabidopsis, and it is not known how the different patterns evolved.In this study, we analyzed superrosid speciesRhodiola rosea,Boehmeria nivea, andCucumis sativusfor their root epidermal cell patterns. Combining phylogenetics, transcriptomics, and cross‐species complementation, we analyzed homologs of the Arabidopsis patterning genes from these species.We identifiedR. roseaandB. niveaas Type III species andC. sativusas Type I species. We discovered substantial similarities in structure, expression, and function of Arabidopsis patterning gene homologs inR. roseaandB. nivea, and major changes inC. sativus.We propose that in superrosids, diverse Type III species inherited the patterning GRN from a common ancestor, whereas Type I species arose by mutations in multiple lineages.
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- PAR ID:
- 10404952
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 238
- Issue:
- 6
- ISSN:
- 0028-646X
- Format(s):
- Medium: X Size: p. 2410-2426
- Size(s):
- p. 2410-2426
- Sponsoring Org:
- National Science Foundation
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