Suppression of Pythium-Rhizoctoni Root Rots by Trichoderm pseudokoningii Tr905 Pul Hrvey CSIRO Sustinble Agriculture Flgship April 2011
Aims Suppression of Pythium-Rhizoctoni Complex: Trichoderm Tr905 Define root disese suppressive efficcy of T. pseudokoningii incidence & severity of Pythium-Rhizoctoni complexes (cerels) Impcts of Tr905 inocultion on soil-borne microbil communities moleculr ecology : shifts in microbil community composition Mechnism of pthogen inhibition & disese suppression pthogen ecology : intr-specific genotypic interctions on roots
Anlyses of soil-borne microbil communities Soils bulk (pre-sowing) quntify pthogens : isoltion rhizosphere (10 week) community : bcteril & fungl T-RFLP Roots quntify : isoltion ID : PCR & sequence Bute Young popultion : AFLP
Pythium & Rhizoctoni Root Isoltions Pythium metlxyl untreted Rhizoctoni Pythium root rot complex irregulre (Clde F) proecndrum (F) heterothllicum (I) rostrtum (E1) Rhizoctoni complex R. solni AG8 R. solni AG2, AG4 R. oryze Dominnt pthogens Pythium irregulre R. solni AG8 SAF 1180.5 : Moleculr Ecology
Bute : Tr905 suppression Pythium & Rhizoctoni Root Rot Root Isoltion (f) Pythium irregulre Rhizoctoni solni LSD = 0.134 LSD = 0.118 0.4 P < 0.05 3.0 Grin Yield (T H -1 ) Not Significnt 0.3 2.9 0.2 0.1 0.0 b bc 39 bc 13 bc 33 Untreted Fungicide Tr905 c 50 2.8 2.7 2.6 2.5 5 4 Untreted Control Metlxyl Fungicide Tr905 Tk7 1 6
Disese Suppression : Trichoderm Tr905 Incidence & severity of root diseses (Pythium, Rhizoctoni) root infection frequencies & ID (species-specific PCR, sequence) Impcts of inocultion on soil-borne microbil communities moleculr ecology : shifts in microbil community composition Mechnism of pthogen inhibition & disese suppression Pythium Microbil T-RFLP
Moleculr Ecology Fungl Communities : Disese Suppression by Tr905 T-RFLP (ITS-5.8S) 0. t-sowing 1. in-crop (10 weeks) Impcts of Tr905 inoculnt untreted Fungl community structure Tr905 Site : Bute vs Young P<0.001 Time : T0 vs T1 P<0.001 Tr905 : no significnt impcts Time P<0.001 Pythium suppression P<0.05 Rhizoctoni suppression P<0.05 Bute Tretment Not Signif. Young
Disese Suppression : Trichoderm Tr905 Incidence & severity of root diseses (Pythium, Rhizoctoni) root infection frequencies & ID (species-specific PCR, sequence) Impcts of inocultion on soil-borne microbil communities moleculr ecology : shifts in microbil community composition Mechnism of pthogen inhibition & disese suppression pthogen ecology : intr-specific genotypic interctions on roots Pythium AFLP Microbil T-RFLP
Pythium irregulre : host-bsed selection MN Brley Clre SA SW KP TR whet brley WP SP CN Genetic Identity (I) rottion W C B Different crops shift genetic structure of popultions continuous G ST : host-bsed popultions (p<0.01) isoltes differentil pthogenicity : (p<0.05) Hrvey et l. (2001), (2006) Effects of disese suppressive Trichoderm inoculnt?
Moleculr Ecology Trichoderm Suppression Pythium-Rhizoctoni Bute AFLP : 2 primer combintions 50 isoltes per loction 25 isoltes per tretment Young Bute untreted +Tr905-42 P<0.05 Bute Young -5 NS
Tr905 : Genetic Differentition of Pthogens Pythium irregulre Rhizoctoni solni AG8 untreted untreted P<0.015 Bute P<0.003 Bute Tr905 untreted P<0.001 Tr905 untreted P<0.001 P<0.004 Young P<0.001 Young Tr905 Tr905
Root Disese Suppression : Trichoderm Tr905 Tr905 : suppressed P. irregulre & R. solni root disese (cerels) effective t moderte inoculum levels Tr905 : no significnt impcts on microbil community composition trgeting Pythium & Rhizoctoni (rhizoplne) : decresed disese Tr905 : significnt shifts in genetic structure of pthogen popultions inoculnt-medited selection incresed intr-specific diversity incresed rhizosphere competition decresed disese severity
Disese Suppression : On-Going Reserch Tr905 rhizosphere ecology : inoculnt competence & persistence species-specific q-pcr : quntify root & rhizosphere colonistion define disese suppressive efficcies on rottion crops Ecology of Pythium-Rhizoctoni complex : genotypic interctions comprtive pthogenicity : untreted vs Tr905- selected isoltes compre fungicide- & Tr905- treted pthogen popultions
CSIRO Ecosystem Sciences Soil Microbil Ecology Belind Stummer Li Jinhu (GAU) Rosemry Wrren Yng Hetong (SDAS) Pul Hrvey Thnk you Emil: pul.hrvey@csiro.u Web: www.csiro.u/people Contct Us Phone: 1300 363 400 or +61 3 9545 2176 Emil: enquiries@csiro.u Web: www.csiro.u
0.8 0.6 0.4 Pythium irregulre LSD = 0.105 Young : Tr905 suppression Pythium & Rhizoctoni root rot Root Isoltion (f) P<0.05 b 16 Rhizoctoni solni 1 1.5 1.4 1.3 1.2 Grin Yield (T H -1 ) LSD = 0.08 P<0.05 b 24 4 0.2 1.1 0.0 Untreted Fungicide Tr905 1.0 Untreted Control Metlxyl Fungicide Tr905 Tk7 1 6