Microorganisms with biofertilizing and
biocontrol properties in cranberries
Lila N. Salhi, David Bernard-Perron, Suha Jabaji, B. Franz Lang
Overview
 What are plant endophytes?
 Benefits of endophytes for plants
 Only few endophytes are known
 Are there more? what are they good for?
 Result: endophyte diversity is completely
underestimated
 Which ones are beneficial?
 Conclusions : Exiting future opportunities
Why microorganisms?
Every child knows (?):
bacteria dissolve minerals (P, K)
and make them available via plant
roots.
Microbial community is involved in:
 Stimulation of plant growth
 Improvement of soil fertility
Holguin et al., 1999). Ciencia y Desarrollo 25 (No.144): 26-35
Plant growth promoting microorganisms
 Colonize plant roots (rhizosphere and endophytes).
 Dominate in competition with other microbes.
 Promote plant growth by:
1.
Wide spectrum of hormonal stimulation factors
2.
Biofertilization (nutrient solubilization, nitrogen fixation)
3.
Pathogen-control (antibiotics, fungicides, insecticides …)
Rothballer et al., 2003; Gamalero et al., 2004, Persello-Cartieauxet al., 2003
Are endophytes always plant growth promoting?
No!
Potential interaction types
(fluid, sometimes transitional):
Neutral : No effect
Mutualistic : beneficial
Pathogenic : harmful
Zhu et al, 2012
Fungal endophytes of cranberries: little is known
Ericoid mycorrhiza
Dark, septate endophytes
 Growth inside plant cells.
 Hyphae don't extend into soil
 Heterogeneous group
 Darkly-pigmented
 Septate hyphae
Phialocephala fortinii
Rhizoscyphus ericae
Oidiodendron maius
Smith and Read, 2008; Jumpponen and Trappe, 1998
… and bacterial endophytes: even less is known
Pseudomonas syringae
 Gram negative with polar flagella
 Usually a pathogen, but …
 Successful in controlling Cottonball disease (Monilinia
oxycocci)
Pseudomonas sp
voland et al, 1999
Questions and Hypotheses
A much more diverse universe of endophytes?
Which isolates in our microbial collection are beneficial?
How to implant them sustainably with plants ?
Molecular identification of microorganisms
rRNA gene in fungi
1. Isolation from plant tissue
Leave
ITS
ETS
5.8S
18S
28S
IGS
Stem
BMBC-F
Root
18S
ITS1-F
ITS1
ITS2
5.8S
28S
ITS4-R
600 nt
750 nt
2. DNA Extraction and PCR
rRNA gene in bacteria
3. DNA Sequencing and Blast
(NCBI)
BLAS
T
27-F
16S
534-R
23S
tRNA
5S
tRNA
507 nt
Muyzer et al. (1993) ; White et al. 1990; blast.ncbi.nlm.nih.gov
Checking of microorganism properties
Phosphate
solubilization
NBRIP medium
Insoluble
phosphate
Halo representing
mineral solubilization
Nitrogen
fixation
Nitrogen
free medium
Bacterial
growth
Biocontrol
PDA medium
Fungal or bacterial
growth inhibition
Results
1 – Microbial Diversity
2 – Beneficial Proprieties
Unexpected endophyte diversity: the tip of an iceberg?
Roots
65 Fungi, 36 Bacteria
137 microorganisms isolated
Fungi
Others
14, 18
4, 3%
%
Stems
Leaves
6, 4%
75%
Roots
Not identified
Trimmatostroma
betulinum
Bacteria :
Bacillus sp.
Paenibacillus sp
Pantoea sp
Stems
16 Fungi, 8 Bacteria
Fungi:
14, 18
%
Stems
Others
4, 3%
Leaves
6, 4%
75%
Roots
Nemania serpens
Alternaria sp.
Bacteria:
Paenibacillus sp.
Leaves
8 Bacteria
Bacteria:
14, 18
%
Stems
Others
4, 3%
Leaves
6, 4%
Roots
75%
Bacillus subtilis
Which endophytes may be beneficial?
Phosphate solubilization
Bacillus subtilis
Burkholderia sp.
Rahnella aquatilis
Nitrogen fixation
Rhodococcus qingshengii
Burkholderia sp.
Rahnella aquatilis
Panteoa sp.
Cohnella ginsengisoli
Rhizobium sp.
Biocontrol
Pseudomonas sp.
Penicillium janthinellum
Bacterial-fungal
interaction
Fungal-fungal
interaction
Conclusions
 Unexpectedly large endophyte diversity in cranberry tissues
 Different types of microbes in roots and aerial plant parts.
 Some endophytes have plant growth promoting properties.
 Others have strong fungicide properties.
What Next?
Thanks !
This work was possible thanks to financial support by
Le ministère de l'Agriculture, des Pêcheries et de
l'Alimentation du Québec