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Biology subjects

Ambrosano, G. B.

Publications and source records attributed to Ambrosano, G. B..

2 recordsLinked to original sources

Tests for segregation distortion in higher ploidy F1 populations

F1 populations are widely used in genetic mapping studies in agriculture, where known pedigrees enable rigorous quality control measures such as segregation distortion testing. However, conventional tests for segregation distortion are inadequate for polyploids, as they fail to account for double reduction, preferential pairing, and genotype uncertainty, leading to inflated type I error rates. Gerard et al. (2025) (doi:10.1007/s00122-025-04816-z) developed a statistical framework to address these issues in tetraploids. Here, we extend these methods to higher even ploidy levels and introduce additional strategies to mitigate the influence of outliers. Through extensive simulations, we demonstrate that our tests maintain appropriate type I error control while retaining power to detect true segregation distortion. We further validate our approach using empirical data from a hexaploid mapping population. Our methods are implemented in the segtest R package, available on the GitHub (https://github.com/dcgerard/segtest).

bioinformatics↗

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↗