Glossary
Bacterial endophytes: bacteria that occur inside a plant (‘: endo’, inside;
‘phyte’, plant). In practical terms, bacteria that can be isolated from surfacesterilized
plant tissue [6,7].
Colonization traits: bacterial traits that are involved in the plant colonization
process.
Competent endophytes: microorganisms that successfully colonizes a plant
by actively entering plant tissue and that have the capacity to modulate plant
physiology and be selectively favored, leading to beneficial maintenance of the
plant–microbe association.
Endosphere: the microenvironment inside the plant (between plant cells) that
is colonized by microorganisms. The endosphere consists of the endorhizosphere
(internal root tissue) and the endophyllosphere (internal shoot and leaf
tissue).
Exosphere: the environment outside the plant, which might or might not be
directly influenced by the plant. This includes the rhizosphere and the
rhizoplane.
Facultative endophytes: organisms that can (optionally) live inside plants and
in other habitats.
Obligate endophytes: organisms that are strictly bound to life inside a plant
during their entire lifespan and that do not posses life stages outside the plant,
except for plant-to-plant and plant-to-insect-to-plant transmission.
Opportunistic endophytes: organisms that occasionally enter plants and profit
from the plant internal environment (nutrient availability, protection and lack of
competition) [20].
Passenger endophytes: endophytes that enter the plant by accident in the
absence of selective forces maintaining it in the internal tissue of the plant.
Phytosphere: the area influenced by plants.
Rhizobacteria: soil bacteria that live under direct influence of plant roots. The
term is often used for plant growth promoting rhizobacteria (PGPR), referring
to beneficial plant–microbe interactions.
Rhizoplane: the surface of plant roots.
Rhizosphere: the narrow layer of soil in the vicinity of plant roots that is
directly influenced by the root [56].