Biology subjects

Sablowski, R.

Publications and source records attributed to Sablowski, R..

4 recordsLinked to original sources

bioRxiv2024

Growth arrest is a DNA damage protection strategy in plants

When exposed to stress, plants slow down their growth while activating defensive mechanisms. This behaviour has been proposed to help plants reallocate resources and meet the energy demands required for survival. In this study, we show instead that plants can grow under limited water availability without compromising their tolerance to the stress. However, cells that continue to divide under stress accumulate DNA damage, which frequently leads to cell death. Given that the DNA lesions are observed in the apical stem cells that give rise to all plant organs, including flowers, we propose that systemic growth arrest is used as a defense strategy that plants employ not only to maximize individual fitness, but also to ensure the accurate transmission of genetic information to their progeny.

plant biology↗

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↗

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↗

bioRxiv2022

Stem cell regulators control a G1 duration gradient in the plant root meristem

In meristems, where new plant organs initiate, key stem cell regulators have been identified, but their link to cell cycle progression remains unclear. Here, we show that the root meristem has a positional gradient of G1 duration that ranges from [~]2 h near the meristem boundary to more than 20 h in stem cells and early derivatives. Mutants in the PLETHORA (PLT) genes shortened G1 length and flattened its gradient. Computer modeling of an incoherent feed-forward loop (IFFL) predicted the inference of a negative regulatory pathway. We propose that PLT genes play opposing roles, maintaining meristem and stem cell activity and inhibiting G1 progression through the CDK inhibitor KRP5, a PLT target, and RBR1. This establishes a previously undescribed proximal-distal feature of the root meristem in which a G1 duration gradient is shaped by stem cell and meristem maintenance regulators.

plant biology↗