The role of floral organs in carpels, an Arabidopsis loss-of-function mutation in MicroRNA160a, in organogenesis and the mechanism regulating its expression

Abstract

SUMMARYMicroRNAs (miRNAs) have emerged as key regulators of gene expression at the post-transcriptional level in both plants and animals. However, the specific functions of MIRNAs (MIRs) and the mechanisms regulating their expression are not fully understood. Previous studies showed that miR160 negatively regulates three genes that encode AUXIN RESPONSE FACTORs (ARF10,. Here, we characterized floral organs in carpels (foc), an Arabidopsis mutant with a Ds transposon insertion in the 3¢ regulatory region of MIR160a. foc plants exhibit a variety of intriguing phenotypes, including serrated rosette leaves, irregular flowers, floral organs inside siliques, reduced fertility, aberrant seeds, and viviparous seedlings. Detailed phenotypic analysis showed that abnormal cell divisions in the basal embryo domain and suspensor led to diverse defects during embryogenesis in foc plants. Further analysis showed that the 3¢ region was required for the expression of MIR160a. The accumulation of mature miR160 was greatly reduced in foc inflorescences. In addition, the expression pattern of ARF16 and -17 was altered during embryo development in foc plants. foc plants were also deficient in auxin responses. Moreover, auxin was involved in regulating the expression of MIR160a through its 3¢ regulatory region. Our study not only provides insight into the molecular mechanism of embryo development via MIR160a-regulated ARFs, but also reveals the mechanism regulating MIR160a expression.

Short tandem target mimic rice lines uncover functions of miRNAs in regulating important agronomic traits

“…4 Q and T), as expected. miR160 is a highly conserved miRNA family that controls root, embryo, leaf, and floral organ development as well as seed germination in Arabidopsis by negatively regulating auxin response factor (ARF) family genes (41)(42)(43)(44). Rice STTM160 transgenic lines shared some phenotypic alterations with Arabidopsis, such as reduced plant height (Fig.…”

Cleavage of INDOLE-3-ACETIC ACID INDUCIBLE28 mRNA by MicroRNA847 Upregulates Auxin Signaling to Modulate Cell Proliferation and Lateral Organ Growth in Arabidopsis

“…miR165/166 and miR319 regulate leaf development and morphogenesis by targeting gene transcripts encoding HD-ZIP and TCP transcription factors, respectively Rhoades et al, 2002;Palatnik et al, 2003;Tang et al, 2003;Juarez et al, 2004). miR160, miR167, and miR390 play roles in root and lateral root development, as well as embryo, leaf, and floral organ development, by targeting transcripts of Auxin Response Factor10 (ARF10)/ARF16/ARF17, ARF6/ARF8, and ARF2/ARF3/ARF4 genes, respectively (Mallory et al, 2005;Wang et al, 2005;Wu et al, 2006;Gutierrez et al, 2009;Liu et al, 2010;Marin et al, 2010;Yoon et al, 2010). While miR160 and miR167 directly target their ARF transcripts, miR390 targets Trans-Acting siRNA3 to trigger the biogenesis of trans-acting small interfering RNAs, which subsequently inhibit ARF2/ARF3/ARF4 to release the repression of lateral root growth (Marin et al, 2010;Yoon et al, 2010).…”

Molecular Mechanism of microRNA396 Mediating Pistil Development in Arabidopsis

“…The specific functions of miRNAs in floral development have been characterized. For example, Arabidopsis (Arabidopsis thaliana) microRNA160a (miR160a) mutant produced floral organs in carpels (Liu et al, 2010). Overexpression of miR164 led to flowers with fused sepals, which resembled the flowers of its target mutants, cuc1cuc2 (for cup-shaped cotyledon1cup-shapedcotyledon2; Mallory et al, 2004).…”