Addison, M. | bioRxiv Science

bioRxiv2020

Characterization of Metarhizium majus (Hypocreales: Clavicipitaceae) isolated from the Western Cape province, South Africa

Entomopathogenic fungi (EPF) are important soil-dwelling entomopathogens, which can be used as biocontrol agents against pest insects. During a survey of the orchard soil at an organic farm, the EPF were identified to species level, using both morphological and molecular techniques. The EPF were trapped from soil samples, taken from an apricot orchard, which were baited in the laboratory, using susceptible host insects. The identification of Metarhizium majus from South African soil, using both morphological and molecular techniques, is verified. The occurrence of M. majus in the South African soil environment had not previously been reported.

microbiology↗

bioRxiv2019

Actomyosin regulation by Eph receptor signaling couples boundary cell formation to border sharpness

The segregation of cells with distinct regional identity underlies formation of a sharp border, which in some tissues serves to organise a boundary signaling centre. It is unclear whether or how border sharpness is coordinated with induction of boundary-specific gene expression. We show that forward signaling of EphA4 is required for border sharpening and induction of boundary cells in the zebrafish hindbrain, which we find both require kinase-dependent signaling, with a lesser input of PDZ domain-dependent signaling. We find that boundary-specific gene expression is regulated by myosin II phosphorylation, which increases actomyosin contraction downstream of EphA4 signaling. Myosin phosphorylation leads to nuclear translocation of Taz, which together with Tead1a is required for boundary marker expression. Since actomyosin contraction maintains sharp borders, there is direct coupling of border sharpness to boundary cell induction that ensures correct organisation of signaling centres.

developmental biology↗