The miR164‐GhCUC2‐GhBRC1 module regulates plant architecture through abscisic acid in cotton

Abstract

Summary Branching determines cotton architecture and production, but the underlying regulatory mechanisms remain unclear. Here, we report that the miR164‐GhCUC2 (CUP‐SHAPED COTYLEDON2) module regulates lateral shoot development in cotton and Arabidopsis. We generated OE‐GhCUC2m (overexpression GhCUC2m) and STTM164 (short tandem target mimic RNA of miR164) lines in cotton and heterologous expression lines for gh‐miR164, GhCUC2 and GhCUC2m in Arabidopsis to study the mechanisms controlling lateral branching. GhCUC2m overexpression resulted in a short‐branch phenotype similar to STTM164. In addition, heterologous expression of GhCUC2m led to decreased number and length of branches compared with wild type, opposite to the effects of the OE‐gh‐pre164 line in Arabidopsis. GhCUC2 interacted with GhBRC1 and exhibited similar negative regulation of branching. Overexpression of GhBRC1 in the brc1‐2 mutant partially rescued the mutant phenotype and decreased branch number. GhBRC1 directly bound to the NCED1 promoter and activated its transcription, leading to local abscisic acid (ABA) accumulation and response. Mutation of the NCED1 promoter disrupted activation by GhBRC1. This finding demonstrates a direct relationship between BRC1 and ABA signalling and places ABA downstream of BRC1 in the control of branching development. The miR164‐GhCUC2‐GhBRC1‐GhNCED1 module provides a clear regulatory axis for ABA signalling to control plant architecture.

The Identification of Small RNAs Differentially Expressed in Apple Buds Reveals a Potential Role of the Mir159-MYB Regulatory Module during Dormancy

“…The miR164-CUC module seems conserved in other plant species and in cotton (Gossypium hirsutum) gh-miR164 and gh-CUC2 form a regulatory gene network with BRANCHED 1 (BRC1) that is believed to control branching. BRC1 encodes a TF that controls branching in several plant species [60,61] and it is part of a GRN controlling dormancy and budbreak in apple [5]. Therefore, the downregulation of mdm-miR164c that we observed at ecodormancy (stage 4) (Table 2 and Figure 2C) could be involved in a BRC1-mediated mechanism of budbreak control in apple.…”

Cyclanilide Induces Lateral Bud Outgrowth by Modulating Cytokinin Biosynthesis and Signalling Pathways in Apple Identified via Transcriptome Analysis

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Photocontrol of Axillary Bud Outgrowth by MicroRNAs: Current State-of-the-Art and Novel Perspectives Gained From the Rosebush Model

“…In Arabidopsis, miR164 targets a subset of the NAC genes, including CUP-SHAPED COTYLEDON (CUC) genes that are important for a wide range of meristem-related developmental processes. Recent studies performed in cotton and in the heterologous Arabidopsis system suggest that repression of CUC2 by miR164 is important for branch outgrowth (Zhan et al, 2021). Specifically, CUC2 interaction with BRC1 may modulate ABA levels to control bud growth (Zhan et al, 2021).…”