Biology subjects

Souza, C. d. S.

Publications and source records attributed to Souza, C. d. S..

2 recordsLinked to original sources

bioRxiv2024

Age-dependent miR156-targeted SPLs are required for extrafloral nectary development in Passiflora spp.

- Passion flower extrafloral nectaries (EFNs) protrude from adult leaves and facilitate mutualistic interactions with insects, but how age cues control EFN establishment remains poorly understood. - Here, we combined genetic and molecular studies to investigate how leaf development and EFN patterning are regulated through the age-dependent miR156-SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) module in two EFN-containing Passiflora species with distinct leaf shapes. - Low levels of miR156 correlate with leaf maturation and EFN formation in Passiflora edulis and P. cincinnata. Consistently, overexpression of miR156 (miR156-OE), which leads to low levels of SPLs, affected leaf ontogeny and EFN development in both species. Laminar EFNs were underdeveloped and less abundant in both P. edulis and P. cincinnata miR156-OE leaves. Importantly, the ecological relationships established by EFNs and their sugar profiles were negatively regulated by high levels of miR156. Moreover, transcriptome analysis of young leaf primordia revealed that miR156-targeted SPLs may be required for proper expression of leaf and EFN development- associated genes in P. edulis and P. cincinnata. - Our work provides the first evidence that the highly conserved miR156/SPL module regulates EFN development in an age-dependent manner and that the program responsible for EFN development is closely associated with the heteroblastic developmental program of the EFN-bearing leaves.

plant biology↗

bioRxiv2020

Genome-wide Identification of the Genetic Basis of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is an archetypal complex disease centered on progressive death of motor neurons. Despite heritability estimates of 52%, GWAS studies have discovered only seven genome-wide significant hits, which are relevant to <10% of ALS patients. To increase the power of gene discovery, we integrated motor neuron functional genomics with ALS genetics in a hierarchical Bayesian model called RefMap. Comprehensive transcriptomic and epigenetic profiling of iPSC-derived motor neurons enabled RefMap to systematically fine-map genes and pathways associated with ALS. As a significant extension of the known genetic architecture of ALS, we identified a group of 690 candidate ALS genes, which is enriched with previously discovered risk genes. Extensive conservation, transcriptome and network analyses demonstrated the functional significance of these candidate genes in motor neurons and disease progression. In particular, we observed a genetic convergence on the distal axon, which supports the prevailing view of ALS as a distal axonopathy. Of the new ALS genes we discovered, we further characterized KANK1 that is enriched with coding and noncoding, common and rare ALS-associated genetic variation. Modelling patient mutations in human neurons reduced KANK1 expression and produced neurotoxicity with disruption of the distal axon. RefMap can be applied broadly to increase the discovery power in genetic association studies of human complex traits and diseases.

genomics↗