Transcript PPT
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.
2.
3.
Wide spectrum of hormonal stimulation factors Biofertilization (nutrient solubilization, nitrogen fixation) Pathogen-control (antibiotics, fungicides, insecticides …)
Rothballer et al., 2003; Gamalero et al., 2004,
Persello-Cartieaux
et 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
Growth inside plant cells.
Hyphae don't extend into soil
Dark, septate endophytes
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)
voland et al, 1999
Pseudomonas sp
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
5.8S
ETS 18S 28S IGS
Stem Root
BMBC-F ITS1-F
18S ITS1 5.8S
600 nt 750 nt
ITS2 28S
ITS4-R 2. DNA Extraction and PCR
rRNA gene in bacteria
27-F
16S
534-R
507 nt
tRNA 23S 5S tRNA
Muyzer et al. (1993) ; White et al. 1990; blast.ncbi.nlm.nih.gov
3. DNA Sequencing and Blast (NCBI)
BLAS T
Checking of microorganism properties Phosphate solubilization Nitrogen fixation Biocontrol
NBRIP medium Insoluble phosphate Nitrogen free medium PDA medium Halo representing mineral solubilization Bacterial growth Fungal or bacterial growth inhibition
Results
1 – Microbial Diversity 2 – Beneficial Proprieties
Unexpected endophyte diversity: the tip of an iceberg? 137 microorganisms isolated Fungi Roots
65 Fungi, 36 Bacteria
Leaves 6, 4% 14, 18 % Others 4, 3% Stems Roots 75%
Not identified Trimmatostroma betulinum
Bacteria :
Bacillus sp.
Paenibacillus sp Pantoea sp
Fungi: Stems
16 Fungi, 8 Bacteria
Leaves 14, 18 % Stems Others 4, 3% 6, 4% Roots 75%
Nemania serpens
Bacteria
: Alternaria sp.
Paenibacillus sp.
Leaves 6, 4% 14, 18 % Stems Others 4, 3% Roots 75% Bacteria
:
Leaves
8 Bacteria
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.
Pseudomonas sp.
Biocontrol
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