Fig. 4: Colonization of anther and pollen grains of A. chinensis sp by Pseudomonas syringae pv. actinidiae expressing a green fluorescent protein (CFBP7286-GFPuv). | Horticulture Research

Fig. 4: Colonization of anther and pollen grains of A. chinensis sp by Pseudomonas syringae pv. actinidiae expressing a green fluorescent protein (CFBP7286-GFPuv).

From: Pathways of flower infection and pollen-mediated dispersion of Pseudomonas syringae pv. actinidiae, the causal agent of kiwifruit bacterial canker

Fig. 4

Fluorescent steromicroscope (ac) and confocal laser scanning (fk) photographs of Actinidia chinensis var. chinensis anthers colonized by Pseudomonas syringae pv. actinidiae expressing a green fluorescent protein (CFBP7286-GFPuv). Inoculation was performed by spraying flowers with a suspension of CFBP7286-GFPuv cells. Photographs were taken 48 h after inoculation. a Healthy anther. The faint yellow-green signal is due to the natural fluorescence of pollen. After pollination of the flowers with contaminated pollen. b Dehiscent anthers showing epiphytic punctiform colonies of CFBP7286-GFPuv. c Anther with epiphytic aggregated colonies of CFBP7286-GFPuv. dg Dehiscent anthers endophytically colonized by CFBP7286-GFPuv. The bacterial colonization of the endotecium is visible at dehiscence when pollen sacks open (d). The tapetum (t), which is the tissue responsible for pollen nutrition and maturation, is highly colonized by the pathogen (e). f The focus of infection is concentrated at the filament (f), suggesting that the pathogen reached the anthers by endophytic migration along vascular bundles. Stomia (st) are visible. hk Magnification of a stomium showing pollen grains colonized by bacterial cells (h, j). i Collapsed cells of the tapetum (t) with extra- and endocellular colonization by CFBP7286-GFPuv. In all micrographs, each bright green, rod-shaped structure is a single CFBP7286-GFPuv cell. Bar measure is reported in each panel

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