Tiller Bud Formation Regulators MOC1 and MOC3 Cooperatively Promote Tiller Bud Outgrowth by Activating FON1 Expression in Rice

Abstract

Tillering in rice is one of the most important agronomic traits. Rice tiller development can be divided into two main processes: the formation of the axillary bud and its subsequent outgrowth. Several genes critical for bud formation in rice have been identified by genetic studies; however, their molecular functions and relationships are still largely unknown. Here, we report that MONOCULM 1 (MOC1) and MONOCULM 3/ TILLERS ABSENT 1/STERILE AND REDUCED TILLERING 1 (MOC3/TAB1/SRT1), two vital regulators for tiller formation in rice, physically interact to regulate tiller bud outgrowth through upregulating the expression of FLORAL ORGAN NUMBER1 (FON1), the homolog of CLAVATA1 in rice. We found that MOC3 is able to directly bind the promoter of FON1 and subsequently activate FON1 expression. MOC1 functions as a coactivator of MOC3, whereas it could not directly bind the FON1 promoter, and further activated FON1 expression in the presence of MOC3. Accordingly, FON1 is highly expressed at axillary meristems and shows remarkably decreased expression levels in moc1 and moc3 mutants. Loss-of-function mutants of FON1 exhibit normal bud formation but defective bud outgrowth and reduced tiller number. Collectively, these results shed light on a joint transcriptional regulatory mechanim by MOC1 and MOC3, and establish a new framework for the control of tiller bud formation and outgrowth.

Identification of the WUSCHEL-Related Homeobox (WOX) Gene Family, and Interaction and Functional Analysis of TaWOX9 and TaWUS in Wheat

“…There are at least 13 WOX proteins in rice (Oryza sativa L.) The MONOCULM 3/TILLERS ABSENT 1/STERILE AND REDUCED TILLERING 1 (MOC3/TAB1/SRT1) protein, an ortholog of WUSCHEL, is required for tiller bud formation and female fertility in rice, and has a complex relationship with cytokinins [15,16]. The MOC1 and MOC3 proteins physically interact to regulate tiller bud outgrowth by upregulating the expression of FLORAL ORGAN NUMBER1 (FON1), the orthologs of CLAVATA1 in rice, in a similar manner to CLV signaling in Arabidopsis [17]. The rice narrow leaf2 and narrow leaf3 loci encode an identical OsWOX3A (OsNS) transcriptional activator, orthologs to NARROW SHEATH1 (NS1) and NS2 in maize (Zea mays L.) and PRESSED FLOWER in Arabidopsis.…”

Genome-wide small RNA profiling reveals tiller development in tall fescue (Festuca arundinacea Schreb)

“…Between Tillering and Pre-tillering, 1140 target genes of miRNA were identified and categorized into 42 GO functional subcategories which were fewer than between Ch-3 and Ch-5. Molecular function (MF) showed the highest enrichment in Tillering and Pre-tillering, and oxidoreductase activity (32, 9.58%), coenzyme binding (19, 5.69%) and cofactor binding (21,6.29%) were the most abundant GO terms, which were different with the dominant GO terms enriched in BP and CC in Ch-3 and Ch-5. However, we found some coenriched target genes in both Ch-3/Ch-5 and Tillering/ Pre-tillering groups using KEGG analysis ( Fig.…”

“…Under optimal growth environment, tall fescue develops tertiary, quartus and more tillers. It is well reported that tillering is a complex trait that can be regulated by multiple factors such as endogenous hormones level, water, fertilizer, light, temperature, genes, and miRNA [6,7].…”

Base Editing: The Ever Expanding Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Tool Kit for Precise Genome Editing in Plants

“…The development of genome-editing technology has revolutionized agricultural studies, enabling the improvement of different plant traits [1][2][3][4][5]. Various tools have been widely used for precise genome editing in plants, including clustered regularly interspaced short palindromic repeats (CRISPR) based gene editing techniques, such as CRISPR/CRISPR associated protein 9 (Cas9), CRISPR/Cas12a (Cpf1), and CRISPR/Cas13 [6][7][8][9], owing to their reliability.…”