Vielle-Calzada, J. P. | bioRxiv Science

bioRxiv2020

The Arabidopsis TTL3 protein interconnects brassinosteroid signalling and cytoskeleton during lateral root development

Lateral roots are essential components of the plant edaphic interface, contributing to water and nutrient uptake, biotic and abiotic interactions, stress survival, and plant anchorage. We have identified the TETRATRICOPEPTIDE-REPEAT THIOREDOXIN-LIKE 3 (TTL3) being related to lateral root emergence and later development. TTL3 interacts with microtubules and potentially interconnects cytoskeletal function with the brassinosteroid signalling pathway. Loss of function of TTL3 leads to a reduced number of emerged lateral roots due to delayed development of lateral root primordia. Lateral root growth of the ttl3 mutant is less sensitive to BR treatment. Timing and spatial distribution of TTL3 expression is consistent with its role in development of lateral root primordia before their emergence and subsequent development into lateral roots. TTL3 is a novel component of the root system morphogenesis regulatory network.

developmental biology↗

bioRxiv2020

Atypical DNA methylation, sRNA size distribution and female gametogenesis correlate with genome compaction in Utricularia gibba

O_LIThe most studied DNA methylation pathway in plants is the RNA Directed DNA Methylation (RdDM), which is a conserved mechanism that involves noncoding-RNAs to control the expansion of intergenic regions. However, little is known about relationship between plant genome size reductions and DNA methylation. C_LIO_LIBecause the compact genome size of the carnivorous plant Utricularia gibba, we investigate in this plant the noncoding-RNA landscape and DNA methylation through a combination of cytological, evolutionary, and genome-wide transcriptomic and methylation approaches. C_LIO_LIWe report an unusual distribution of noncoding RNAs in U. gibba in comparison with other characterized angiosperms, which correlated with a lower level of global genome methylation, as determined by a novel strategy based on long-read DNA sequencing and corroborated by whole-genome bisulfite analysis. Moreover, found that genes involved in the RdDM pathway may not be functionally active in U. gibba, including a truncated DICER-LIKE 3 (DCL3), involved in the production of 24-nt small-RNAs. C_LIO_LIOur findings suggest that selective pressure to conserve a fully functional RdDM pathway might be reduced in compact genomes and a defective DCL3 correlate with a decreased proportion of 24-nt small-RNAs and developmental alterations in U. gibba, which could represent an initial step in the evolution of apomixis. C_LI

plant biology↗