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Berti, L.

Publications and source records attributed to Berti, L..

2 recordsLinked to original sources

Sequencing by avidity enables high accuracy with low reagent consumption

We present avidity sequencing - a novel sequencing chemistry that separately optimizes the process of stepping along a DNA template and the process of identifying each nucleotide within the template. Nucleotide identification uses multivalent nucleotide ligands on dye-labeled cores to form polymerase-polymer nucleotide complexes bound to clonal copies of DNA targets. These polymer-nucleotide substrates, termed avidites, decrease the required concentration of reporting nucleotides from micromolar to nanomolar, and yield negligible dissociation rates. We demonstrate the use of avidites as a key component of a sequencing technology that surpasses Q40 accuracy and enables a diversity of applications that include single cell RNA-seq and whole human genome sequencing. We also show the advantages of this technology in sequencing through long homopolymers.

genomics↗

Plasticity of the xylem vulnerability to embolism in poplar relies on quantitative pit properties rather than on pit structure

Knowledge on variations of drought resistance traits are needed to predict the potential of trees to acclimate to coming severe drought events. Xylem vulnerability to embolism is a key parameter related to such droughts, and its phenotypic variability relies mainly on environmental plasticity. We investigated the structural determinants controlling the plasticity of vulnerability to embolism, focusing on the key elements involved in the air bubble entry in a vessel, especially the inter-vessel pits. Poplar saplings (Populus tremula x alba) grown in contrasted water availability or light exposure exhibited differences in vulnerability to embolism in a range of 0.76 MPa. We then characterized the structural changes related to qualitative and quantitative pit characteristics, from the pit structure to the organization of xylem vessels, using different microscopy techniques (TEM, SEM, light). X-ray microtomography analysis allowed observing the vessel vulnerability and testing some of the relationships between structural traits and vulnerability to embolism inside the xylem. The pit ultrastructure did not change, whereas the vessel dimensions increased with vulnerability to embolism and the grouping index and fraction of inter-vessel cell wall decreased with vulnerability to embolism. These findings holds when comparing trees or when comparing vessels inside the xylem. These results evidenced that plasticity of vulnerability to embolism occurs through changes in the quantitative pit properties such as pit area and vessel grouping rather than on the pit structure.

plant biology↗