Auxin signaling modulates LATERAL ROOT PRIMORDIUM1 (LRP1) expression during lateral root development in Arabidopsis

Abstract

SummaryAuxin signaling mediated by various auxin/indole‐3‐acetic acid (Aux/IAAs) and AUXIN RESPONSE FACTORs (ARFs) regulate lateral root (LR) development by controlling the expression of downstream genes. LATERAL ROOT PRIMORDIUM1 (LRP1), a member of the SHORT INTERNODES/STYLISH (SHI/STY) family, was identified as an auxin‐inducible gene. The precise developmental role and molecular regulation of LRP1 in root development remain to be understood. Here we show that LRP1 is expressed in all stages of LR development, besides the primary root. The expression of LRP1 is regulated by histone deacetylation in an auxin‐dependent manner. Our genetic interaction studies showed that LRP1 acts downstream of auxin responsive Aux/IAAs‐ARFs modules during LR development. We showed that auxin‐mediated induction of LRP1 is lost in emerging LRs of slr‐1 and arf7arf19 mutants roots. NPA treatment studies showed that LRP1 acts after LR founder cell specification and asymmetric division during LR development. Overexpression of LRP1 (LRP1 OE) showed an increased number of LR primordia (LRP) at stages I, IV and V, resulting in reduced emerged LR density, which suggests that it is involved in LRP development. Interestingly, LRP1‐induced expression of YUC4, which is involved in auxin biosynthesis, contributes to the increased accumulation of endogenous auxin in LRP1 OE roots. LRP1 interacts with SHI, STY1, SRS3, SRS6 and SRS7 proteins of the SHI/STY family, indicating their possible redundant role during root development. Our results suggested that auxin and histone deacetylation affect LRP1 expression and it acts downstream of LR forming auxin response modules to negatively regulate LRP development by modulating auxin homeostasis in Arabidopsis thaliana.

Genome-Wide Analysis of the Shi-Related Sequence Family and Functional Identification of GmSRS18 Involving in Drought and Salt Stresses in Soybean

“…There are many types derived from typical RING domain, such as RING-V, 2 of 17 RING-D, RING-S/T, RING-G and RING-C2 [6,7]. The IXGH domain contains acidic amino acids, which demonstrate that SRSs possessing IXGH domains are transcriptional activators [2,8].…”

“…They play very important roles in the progress of plant growth. LRP1 was involved in chromatin modification and auxin signaling during lateral root (LR) development by may forming a complex with SHI, STY1, SRS3, SRS6, and SRS7 [8][9][10]. Interestingly, LRP1 as well as STY1 could regulate the expression of YUC4 in the process of auxin biosynthesis [8,11].…”

“…LRP1 was involved in chromatin modification and auxin signaling during lateral root (LR) development by may forming a complex with SHI, STY1, SRS3, SRS6, and SRS7 [8][9][10]. Interestingly, LRP1 as well as STY1 could regulate the expression of YUC4 in the process of auxin biosynthesis [8,11]. STY1 (SRS1) was reported to regulate auxin biosynthesis, affect apical-basal patterning of stamen, influence cell expansion and timing of flowering [12,13].…”

AtDRO1 is nuclear localized in root tips under native conditions and impacts auxin localization

“…WDL1 promotes right-handed helical root growth and was shown to influence slanting via anisotropic cell expansion associated with changes in cortical microtubules (Yuen et al 2003). Auxinmediated chromatin modification was shown to regulate the expression of LRP1 which acts downstream of ARFs to control root elongation and development (Singh et al 2019). These DEGs highlight potential pathways that are disrupted by the loss of DRO1 function and represent future targets to better understand how root GSA is controlled.…”

“…Among the DEGs, we found several auxin-related genes as well as root development-related genes. These included WOX11, known to be involved in lateral root initiation and development and previously implicated in the rice LAZY1-mediated gravistimulation pathway (Zhang et al 2018); LRP1, an auxinresponsive root development gene (Singh et al 2019);and WDL1, which controls anisotropic cell expansion in roots (Yuen et al 2003). A single striking DEG repressed over 2,000 fold in the dro1 mutant was MTO 1 RESPONDING DOWN (MRD1).…”