2 research outputs found
Root hairs play a key role in the endophytic colonization of olive roots by Pseudomonas spp. with biocontrol activity
11 pages; 3 figuresThe use of indigenous bacterial root endophytes
with biocontrol activity against soil-borne phytopathogens
is an environmentally-friendly and ecologically-efficient
action within an integrated disease management framework.
The earliest steps of olive root colonization by Pseudomonas
fluorescens PICF7 and Pseudomonas putida PICP2,
effective biocontrol agents (BCAs) against Verticillium wilt
of olive (Olea europaea L.) caused by the fungus
Verticillium dahliae Kleb., are here described. A gnotobiotic
study system using in vitro propagated olive plants,
differential fluorescent-protein tagging of bacteria, and
confocal laser scanning microscopy analysis have been
successfully used to examine olive roots–Pseudomonas
spp. interactions at the single-cell level. In vivo simultaneous
visualization of PICF7 and PICP2 cells on/in root
tissues enabled to discard competition between the two
bacterial strains during root colonization. Results demonstrated
that both BCAs are able to endophytically colonized
olive root tissues. Moreover, results suggest a pivotal role
of root hairs in root colonization by both biocontrol
Pseudomonas spp. However, colonization of root hairs
appeared to be a highly specific event, and only a very low
number of root hairs were effectively colonized by
introduced bacteria. Strains PICF7 and PICP2 can simultaneously
colonize the same root hair, demonstrating that
early colonization of a given root hair by one strain did not
hinder subsequent attachment and penetration by the other.
Since many environmental factors can affect the number,
anatomy, development, and physiology of root hairs,
colonization competence and biocontrol effectiveness of
BCAs may be greatly influenced by root hair’s fitness.
Finally, the in vitro study system here reported has shown
to be a suitable tool to investigate colonization processes of
woody plant roots by microorganisms with biocontrol
potential.Grants P07-CVI-
02624 (Proyecto de Excelencia, Junta de AndalucĂa, Spain) and
AGL2009-07275 (Spanish Ministerio de Ciencia e InnovaciĂłn, cofinanced by FEDER of the UE).Peer reviewe