Kiwifruit floral gene APETALA2 is alternatively spliced and accumulates in aberrant indeterminate flowers in the absence of miR172

Abstract

In Arabidopsis, the identity of perianth and reproductive organs are specified by antagonistic action of two floral homeotic genes, APETALA2 (AP2) and AGAMOUS (AG). AP2 is also negatively regulated by an evolutionary conserved interaction with a microRNA, miR172, and has additional roles in general plant development. A kiwifruit gene with high levels of homology to AP2 and AP2-like genes from other plant species was identified. The transcript was abundant in the kiwifruit flower, particularly petal, suggesting a role in floral organ identity. Splice variants were identified, all containing both AP2 domains, including a variant that potentially produces a shorter transcript without the miRNA172 targeting site. Increased AP2 transcript accumulation was detected in the aberrant flowers of the mutant ‘Pukekohe dwarf’ with multiple perianth whorls and extended petaloid features. In contrast to normal kiwifruit flowers, the aberrant flowers failed to accumulate miR172 in the developing whorls, although accumulation was detected at the base of the flower. An additional role during dormancy in kiwifruit was proposed based on AP2 transcript accumulation in axillary buds before and after budbreak.

A putative miR172-targeted CeAPETALA2-like gene is involved in floral patterning regulation of the orchid Cymbidium ensifolium

“…Relatively high degrees of homology were also indicated between this cDNA and the AP2-like sequences from Arabidopsis. Additionally, we showed strong complementarity between CeAP2-like mRNA and miR172, as well as localization of the complementary nucleotides similar to that in the cDNAs of other homologous genes identified in different plant species (Nilsson et al, 2007;Varkonyi-Gasic et al, 2012). These results indicated the potential regulation of AP2 by miR172 in the orchid.…”

“…Furthermore, in silico RNA hybridization revealed a sequence complementary to miR172 in the CeAP2-like cDNA, and the position of this sequence was similar to that in other miR172-targeted AP2 genes from different plants (Figure 3). Since the regulation of the AP2-domain genes by miR172 has been broadly reported in both monocotyledons and dicotyledons (Zhu and Helliwell 2011;Varkonyi-Gasic et al, 2012), our findings indicated CeAP2-like as a putative target gene of miR172 in C. ensifolium. …”

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

“…miR172 has been the focus of multiple studies using different approaches, such as overexpression, expression of resistant target genes, or mutations in individual loci encoding the miRNA (26)(27)(28)(29)(30)(31)(32)(33)(34)(35). These previous studies suggested that miR172 mainly controls flowering time and floral organ identity.…”

The Class II Trehalose 6-phosphate Synthase Gene PvTPS9 Modulates Trehalose Metabolism in Phaseolus vulgaris Nodules

“…Excitingly, a sequence alignment of Pv miR172 and the transcript of PvTPS9 , revealed a possible recognition site in the coding region (Figure S4A). The transcript abundance of the canonical target of miR172, APETALA2 ( PvAP2 ), shows an inverse correlation to that of Pv miR172 during nodulation, an indication that Pv miR172 modulates the expression of PvAP2 in P. vulgaris (Mlotshwa et al, 2006; Glazińska et al, 2009; Wollmann et al, 2010; Grigorova et al, 2011; Zhu and Helliwell, 2011; Varkonyi-Gasic et al, 2012). Here, we found that the PvTPS9 transcript was associated with Pv AGO1-complexes from 14 and 22 dpi nodules along with PvAP2 and Pv miR172, despite the fact that 5′-RACE analysis revealed no evidence of processing for the PvTPS9 transcript (Figure S4C).…”