Endophytic colonization of Vitis vinifera L. by Burkholderia phytofirmans strain PsJN: from the rhizosphere to inflorescence tissues

Abstract

The colonization pattern of Vitis vinifera L. by Burkholderia phytofirmans strain PsJN was determined using grapevine fruiting cuttings with emphasis on putative inflorescence colonization under nonsterile conditions. Two-week-old rooted plants harbouring flower bud initials, grown in nonsterile soil, were inoculated with PsJN:gfp2x. Plant colonization was subsequently monitored at various times after inoculation with plate counts and epifluorescence and/or confocal microscopy. Strain PsJN was chronologically detected on the root surfaces, in the endorhiza, inside grape inflorescence stalks, not inside preflower buds and flowers but rather as an endophyte inside young berries. Data demonstrated low endophytic populations of strain PsJN in inflorescence organs, i.e. grape stalks and immature berries with inconsistency among plants for bacterial colonization of inflorescences. Nevertheless, endophytic colonization of inflorescences by strain PsJN was substantial for some plants. Microscopic analysis revealed PsJN as a thriving endophyte in inflorescence organs after the colonization process. Strain PsJN was visualized colonizing the root surface, entering the endorhiza and spreading to grape inflorescence stalks, pedicels and then to immature berries through xylem vessels. In parallel to these observations, a natural microbial communities was also detected on and inside plants, demonstrating the colonization of grapevine by strain PsJN in the presence of other microorganisms.

Endophytic Colonization of Potato ( Solanum tuberosum L.) by a Novel Competent Bacterial Endophyte, Pseudomonas putida Strain P9, and Its Effect on Associated Bacterial Communities

“…For instance, cells of Rhizobium etli G12 (used as a biocontrol agent) marked with a green fluorescent protein were visible in root hairs, around epidermal cells, and within the vascular tissue of Arabidopsis thaliana plants (22), and these plants exhibited maximum control of the nematode Meleidogyne incognita. Moreover, cells of the green fluorescent protein-labeled plant-growth-promoting bacterial strain Burkholderia phytofirmans PsJN were present in xylem vessels and different plant organs, including inflorescences, of grape plants (7). Endophytic colonization was also observed for the nitrogen-fixing bacteria Acetobacter diazotrophicus in sugarcane (12) and Serratia marcescens in rice (20).…”

Endophytic fungi from Vitis labrusca L. ‘Niagara Rosada’) and its potential for the biological control of Fusarium oxysporum

“…Additionally, the endophytes may induce useful defense responses against pathogens in host plants. The colonization of grapevines by endophytes has Genetics and Molecular Research 11 (4): 4187-4197 (2012) Endophytic fungi from Vitis labrusca been related to the role of endophytic fungi in the biological control of pathogens, mainly Plasmopora viticola (Mostert et al, 2000;Musetti et al, 2006;Compant et al, 2008;Martini et al, 2009).…”

A Decade of Burkholderia cenocepacia Virulence Determinant Research

“…Burkholderia spp. have been described as plant pathogens (7,21,72), symbiotic rhizospheric or endophytic plant growth promoters (35,130), endosymbionts of fungi (5,56,70) and insects (77,144), and animal pathogens (31,59). They can degrade pollutants (25,30,83,84,147), fix nitrogen and solubilize metals for use by their symbiotic partners (25,73), produce compounds that protect their host-associated partners from pathogenic fungi, bacteria, protozoa, and nematodes (26,111,114), and even induce plant host defense mechanisms (37).…”