Unique features of the grapevine VvK5.1 channel support novel functions for outward K+ channels in plants

The unexpected location of VvK5.1 expression detected in the lateral root primordium, berry phloem and pistil provides new insights into the roles that this outward channel type can play in plants.

mCherry-Labeled Verticillium dahliae Could Be Utilized to Investigate Its Pathogenicity Process in Nicotiana benthamiana

Verticillium dahliae is a soil-borne phytopathogenic fungus that causes a destructive vascular wilt, but details of the molecular mechanism behind its pathogenicity are not very clear. Here, we generated a red fluorescent isolate of V. dahliae by protoplast transformation to explore its pathogenicity mechanism, including colonization, invasion, and extension in Nicotiana benthamiana, using confocal microscopy. The nucleotide sequences of mCherry were optimized for fungal expression and cloned into pCT-HM plasmid, which was inserted into V. dahliae protoplasts. The transformant (Vd-m) shows strong red fluorescence and its phenotype, growth rate, and pathogenicity did not differ significantly from the wild type V. dahliae (Vd-wt). Between one and three days post inoculation (dpi), the Vd-m successfully colonized and invaded epidermal cells of the roots. From four to six dpi, hyphae grew on root wounds and lateral root primordium and entered xylem vessels. From seven to nine dpi, hyphae extended along the surface of the cell wall and massively grew in the xylem vessel of roots. At ten dpi, the Vd-m was found in petioles and veins of leaves. Our results distinctly showed the pathway of V. dahliae infection and colonization in N. benthamiana, and the optimized expression can be used to deepen our understanding of the molecular mechanism of pathogenicity.

Ultrastructure of cells in an initiating lateral root primordium of Raphanus sativus

Lateral root primordia in <i>Raphanus sativus</i> had developed 10 hours after main root decapitation. The primordia consisted of three cell layers — basal layer continuous with the pericycle. The primordia were initiated by activated groups of pericycle cells. Inactive pericycle cells with a thin layer of parietal cytoplasme large central vacuole and well developed leucoplasts with starch grains were trans-formed into meristematic cells. During transformation the amount of cytoplasm and number of cytoplasmic organelles greatly increased, the central vacuole disappeared, and an ER system continuous in many places with the nuclear envelope evolved. The lamellar structure of plastids underwent almost complete reduction; the dictyosomes became active. The newly formed meristem differed apparently from the apical root meristem only in the lack or scarcity of lipid bodies and starch.