SHORT‐ROOT and SCARECROW homologs regulate patterning of diverse cell types within and between species

Abstract

Summary The roles of SHORT‐ROOT (SHR) and SCARECROW (SCR) in ground tissue patterning and differentiation have been well established in the root of Arabidopsis 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 the SHR–SCR module further unravels the developmental regulation that controls diverse forms and functions within and between species.

Single-Cell Transcriptomic Analysis Highlights Specific Cell Types of Wheat Manipulated byFusarium graminearumLeading to Susceptibility

“…It prevents systemic colonization by numerous fungal pathogens that typically invade roots radially before spreading via the vasculature to the foliage. Interestingly, a similar cell layer surrounding the vein is observed in stems and leaves (Martins et al, 2011), and is regulated by analogous mechanisms (Shaar-Moshe and Brady, 2023), although the terminology “endodermis” is controversial (Martins et al, 2011). The outer sheath in leaves, developed from the ground meristem like the root endodermis, serves a comparable cell type (Sakaguchi and Fukuda, 2008; Nelson, 2011; Martins et al, 2011; Zeng et al, 2016; Sedelnikova et al, 2018).…”

Peripheral vascular strand development in nodules is controlled by a bHLH/HLH heterodimer

“…The nodule identity is regulated by two paralogs: NODULE ROOT1 (MtNOOT1) and MtNOOT2, which suppress the root developmental program at the nodule apex and express in NVM and NCM respectively (Couzigou et al, 2012;Magne et al, 2018). SHORT-ROOT (SHR) and SCARECROW (SCR) are required for the establishment of the root endodermal cell layer (Shaar-Moshe and Brady, 2022). CK treatment and inoculation with rhizobia promote the accumulation of MtSHR1 and induce the expression of MtSCR.…”