Biology subjects

Nogueira, F. T.

Publications and source records attributed to Nogueira, F. T..

4 recordsLinked to original sources

bioRxiv2023

Gibberellin and the miRNA156-targeted SlSBPs synergistically regulate tomato floral meristem activity and fruit patterning

Many developmental processes associated with fruit development take place at the floral meristem (FM). Age-regulated microRNA156 (miR156) and gibberellins (GA) interact to control flowering time, but their interplay in subsequent stages of reproductive development is poorly understood. Here, we show that GA and miR156 function in tomato FM and fruit patterning. High GA responses or overexpression of miR156 (156OE), which leads to low levels of miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN- LIKE (SPL/SBP), resulted in enlarged FMs, defects in FM determinacy and fruits with increased locule number. Conversely, low GA responses reduced fruit indeterminacy and locule number, and overexpression of a miR156-resistant SlSBP15 allele (rSBP15) reduced cell number and size in the FM, as well as locule number. GA responses were partially required for the fruit defects observed in 156OE and rSBP15 plants. Transcriptome analysis and genetic interactions revealed shared and divergent functions of miR156-targeted SlSBPs, PROCERA/DELLA and the classical WUSCHEL/CLAVATA pathway, which has been previously associated with meristem size and determinacy. Our findings reveal that the miR156/SlSBP/GA regulatory module is deployed differently depending on developmental stage and create novel opportunities to genetically fine-tune aspects of fruit development that have been important for tomato domestication.

plant biology↗

bioRxiv2023

Regulation of PYR/PYL/RCAR ABA receptors mRNA stability: involvement of miR5628 in decay of PYL6 mRNA

Hormone signaling fine-tuning involves feedback regulatory loops. Abscisic acid (ABA) plays key functions in development and tolerance to abiotic stress. ABA is sensed by the PYR/PYL/RCAR receptors and it also represses their gene expression. Conversely, ABA induces PP2C phosphatases expression, which are negative regulators of the ABA signaling pathway. This feedback regulatory scheme is likely important for the modulation of ABA signal transduction. Here, we provide a new insight into the mechanisms underlying the ABA-induced negative control of PYR/PYL/RCAR expression in Arabidopsis thaliana. The strong and sustained repression of PYR/PYL/RCARs revealed by ABA time course treatment defines the regulation of receptors genes as an important step in resetting the ABA signaling pathway. Transcription inhibition by cordycepin showed that destabilization of PYL1/4/5/6 mRNA is involved in ABA-induced repression of these genes. Furthermore, genetic evidence indicated that decapping may play a role in PYL4/5/6 mRNAs decay. In addition, we provide evidence that the Arabidopsis-specific microRNA5628 (miR5628), which is transiently induced by the ABA core signaling pathway, guides the cleavage of PYL6 transcript in response to ABA. After cleavage, the resulting RISC 5- and 3-cleaved fragments of PYL6 mRNA may be degraded by exoribonuclease XRN4. MiR5628 is an evolutionary novelty that may contribute, with decapping and XRN4 activities, to enhance PYL6 mRNA degradation. Thus, control of stability of PYR/PYL/RCAR transcripts is an important step in maintaining homeostasis of ABA signaling. One Sentence SummaryAttenuation of ABA signaling involves destabilization of PYL1/4/5/6 transcripts. ABA core signaling induces miR5628 expression to enhance PYL6 mRNA degradation in conjunction with decapping and XRN4 activities.

plant biology↗

bioRxiv2022

Plant age-dependent dynamics of annatto pigment (bixin) biosynthesis in Bixa orellana L.

Age affects the production of secondary metabolites, but how developmental cues regulate secondary metabolism remains poorly understood. Annatto (Bixa orellana L.) is a source of bixin, an apocarotenoid used in the worlds food industry worldwide. Understanding how age-dependent mechanisms control bixin biosynthesis is of great interest for plant biology and for pharmaceutical, cosmetic, and textile industries. Here, we used genetic and molecular tools to unravel the role of the annatto age regulated miRNA156 (miR156) targeted SQUAMOSA PROMOTER BINDING PROTEIN LIKE (BoSPL) genes in secondary metabolism. Low expression of several BoSPL genes in miR156 overexpressing annatto plants (OE::156) impacted leaf ontogeny, reducing bixin production and increasing abscisic acid (ABA) levels. Modulation of BoCCD4;4 and BoCCD1 expression, key genes in lycopene cleavage, was associated with diverting the carbon flux from bixin to ABA, whereas upregulation of lycopene {beta} cyclase genes implies the xanthophyll biosynthetic pathway acted as a carbon sink in OE::156 plants. Proteomic analyses revealed low accumulation of most secondary metabolite-related enzymes in OE::156 plants, suggesting that miR156 targeted BoSPLs are required to activate several annatto secondary metabolic pathways. Our findings suggest that carbon flux in B. orellana OE::156 leaves was redirected from bixin to ABA production, indicating an age-dependent leaf dynamics of bixin biosynthesis. Importantly, our study opened a new venue to future annatto breeding programs aiming to improve bixin output.

plant biology↗

bioRxiv2022

miR319-targeted TCP4/LANCEOLATE directly regulates OVATE and auxin responses to modulate tomato gynoecium patterning and fruit morphology

Diversity in fruit morphology is one of the hallmarks of varietal differences among modern cultivars of fruit-bearing crops. As evolutionarily related organs, fruits and leaves share developmental processes, but there are surprisingly few connections between regulatory pathways for fruit and leaf development. Here, we show the regulation of the leaf development-associated TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) TCP4/LANCEOLATE (TCP4/LA) transcription factor by the microRNA319 (miR319) is crucial for gynoecium patterning and establishment of fruit morphology. Loss of miR319 regulation leads to a premature, ectopic TCP4/LA expression during gynoecium patterning, which results in elongated fruits, resembling ovate mutants. TCP4/LA modulates tomato fruit development and morphology partially by directly repressing OVATE expression as early as 5-8 days post-inflorescence (dpi) flower buds. Furthermore, miR319-targeted CINCINNATA-like TCP4/LANCEOLATE controls auxin responses in developing flower buds by directly binding to the SlYUCCA4 promoter. Modulation of auxin biosynthesis by TCP4/LA is shared with other CINCINNATA-like TCPs during Arabidopsis gynoecium patterning. Our study defines a novel miRNA-based molecular link between OVATE, a fundamental gene associated with tomato domestication, and auxin responses in the control of fruit development and morphology. Given the striking variation in fruit shape among members of the Solanaceae family, fine-tuning regulation of gene expression by miRNA coupled with modulation of hormone dynamics may be a common driver in the evolution of fruit-shape diversity.

plant biology↗