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Title: Ground tissue circuitry regulates organ complexity in maize and Setaria
Most plant roots have multiple cortex layers that make up the bulk of the organ and play key roles in physiology, such as flood tolerance and symbiosis. However, little is known about the formation of cortical layers outside of the highly reduced anatomy of Arabidopsis . Here, we used single-cell RNA sequencing to rapidly generate a cell-resolution map of the maize root, revealing an alternative configuration of the tissue formative transcription factor SHORT-ROOT (SHR) adjacent to an expanded cortex. We show that maize SHR protein is hypermobile, moving at least eight cell layers into the cortex. Higher-order SHR mutants in both maize and Setaria have reduced numbers of cortical layers, showing that the SHR pathway controls expansion of cortical tissue to elaborate anatomical complexity.  more » « less
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Page Range / eLocation ID:
1247 to 1252
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Summary

    The roles ofSHORT‐ROOT(SHR) andSCARECROW(SCR) in ground tissue patterning and differentiation have been well established in the root ofArabidopsis thaliana. Recently, work in additional organs and species revealed the extensive functional diversification of these genes, including regulation of cortical divisions essential for nodule organogenesis in legume roots, bundle sheath specification in the Arabidopsis leaf, patterning of inner leaf cell layers in maize, and stomatal development in rice. The co‐option of distinct functions and cell types is attributed to different mechanisms, including paralog retention, spatiotemporal changes in gene expression, and novel protein functions. Elaborating our knowledge of theSHRSCRmodule further unravels the developmental regulation that controls diverse forms and functions within and between species.

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