Romani, I. | bioRxiv Science

bioRxiv2023

Mapping the landscape of transcription factor promoter activity during vegetative development in Marchantia

Transcription factors (TFs) are essential for the regulation of gene expression and cell fate determination. Characterising the transcriptional activity of TF genes in space and time is a critical step towards understanding complex biological systems. The vegetative gametophyte meristems of bryophytes share some characteristics with the shoot-apical meristems of flowering plants. However, the identity and expression profiles of TFs associated with gametophyte organization are largely unknown. With only [~]450 TF genes, Marchantia polymorpha is an outstanding model system for plant systems biology. We have generated a near-complete collection of promoter elements derived from Marchantia TF genes. We experimentally tested in planta reporter fusions for all the TF promoters in the collection and systematically analysed expression patterns in Marchantia gemmae. This allowed us to build a map of precise expression domains and identify a unique set of TFs expressed in the stem-cell zone, providing new insight into the dynamic regulation of the gametophytic meristem and its evolution. In addition, we provide an online database of expression patterns for all promoters in the collection. We expect that the promoter elements characterised here will be useful for cell-type specific expression, synthetic biology applications, and functional genomics.

plant biology↗

bioRxiv2022

Candidate proteins associated with popping expansion capacity of popcorn

The mechanical resistance of the popcorn pericarp has a positive and direct relationship to its expansion volume. It allows enough time for the endosperm to gelatinize completely before its extravasation. Expansion is a polygenic trait that has been extensively studied. However, no records in the literature indicate proteins that directly affect pericarp thickness and integrity. Therefore, the present work aimed to identify candidate pericarp proteins associated with the expansion capacity of popcorn kernels using the shotgun proteomic approach. The analyses were carried out in the pericarp of two popcorn inbred lines, P11 (expansion volume of 30 mL g-1) and P16 (expansion volume of 14 mL g-1), in two developmental stages (15 and 25 DAP). A total of 803 non-redundant proteins were identified. Most of them were involved in key processes associated with pericarp development and thickening. Two candidate proteins stood out among the differentially abundant proteins. Peroxidase was up-accumulated in P11/25 DAP (high popping expansion) and was 1.498 times more abundant in this inbred line, while xyloglucan endotransglucosylase/hydrolase was more abundant in P16 (low popping expansion) in both developmental stages. Thus, the peroxidase protein increases expandability, whereas xyloglucan endotransglucosylase/hydrolase decreases it, even though its specific role has not been elucidated. These proteins should be further investigated, as they may be used to improve expansion capacity in popcorn breeding programs.

genomics↗