Maize Genetics Cooperation Newsletter vol 88
2014
Consiglio per la Ricerca e la
sperimentazione in Agricoltura
Unit� di Ricerca per la
Maiscoltura (CRA-MAC)
Via Stezzano 24, 24126 Bergamo
(Italy)
Bilateral collaboration
Italy-Canada for maize Fusarium resistance in the
Canadair project*
Lanzanova, C., Torri, A., Locatelli, S.
and Balconi, C.
e-mail: [email protected]
Within the framework of the
CANADAIR project, a bilateral collaboration between CRA-MAC (Maize Research
Unit of Bergamo-Italy) and ECORC (Agri-Food Canada,
Eastern Cereal and Oilseed Research Centre-Ottawa), will allow achieving a
complementation and integration of transcriptome
data, and the genes that are regulated during maize response both to Fusarium graminearum
and Fusarium verticillioides
will be identified. Commonly regulated genes could act as functional markers of
resistance in both diseases. The tests performed on maize lines will allow the
identification of genetic materials with affordable resistance to both pathogens.
CRA-MAC, recently focused its research activity on the
identification of genetic and molecular bases of maize resistance to F. verticillioides
through i) artificial inoculation screening of
genotypes from breeding programs using the KIA (Kernel Inoculation Assay) on
sib crossed plants and ii) implementation of differentially gene expression
through a RNAseq experiment.
From previous studies (Balconi et al., Phytop. Medit. 53 (1) 14-26,
2014) four Italian inbred lines showed differential
patterns of susceptibility (Lo 43, Lo 186) or resistance (Lo 18, Lo 435) to F. verticillioides.
These materials have been used in transcriptome
analyses (Table1).
The ECORC research Group of Linda Harris is involved
in the investigation of transcriptional changes taking place during maize/ F. graminearum
interaction. The Canadian group carried out transcriptional analyses of
resistant and susceptible maize genotypes, analysing changes in kernel tissues.
In addition, the ECORC group has developed a recombinant inbred line (RIL)
population (F6) of >400 lines derived from CO441 (resistant) x B73
(susceptible), segregating for resistance to F. graminearum. Four RIL lines (RIL
19,RIL 77, RIL 226 resistant and RIL 278 susceptible to F. graminearum) have been used in transcriptome analyses (Table 1).
The collaboration implied the exchange of materials
and data during 2012-2014 period. RNAseq
results will be shared in order to highlight the most repeatable and therefore
affordable data. During 2012 and 2013 seasons, the most F. verticillioides resistant and
susceptible lines identified by CRA-MAC were tested for F. graminearum resistance by the ECORC
group; similarly, the most resistant and susceptible RILs identified by ECORC
were provided to CRA-MAC and tested through field artificial inoculation for
resistance to F. verticillioides.
At 15 DAP (Days After Pollination) the different
materials have been inoculated with a mix of two toxigenic F. verticillioides strains (106
spores/ml) with a multi inoculation assay on sib crossed plants (Figure 1A). At
1 and 5 DAI (Days After Inoculation) 4 ears/treatment as biological replicates
(non-inoculated, sterile water as internal control and Fusarium)
were harvested for molecular analyses (data not shown).
For phenotyping
at 15 DAP the same materials have been inoculated with the same concentration
of spores with a single inoculation assay (Figure 1B). At harvest time
different parameters such as visual rating score (Reid et al., Technical Bull.
1996-5E, 1996), Number of Infected Kernels at the inoculation point (NIK), percentage of
internal infected kernels on DRBC (King et
al., App. and Environ. Microbiol. 37, 959-964,
1979) and fumonisin content, were evaluated.
More in detail, the extension of the mycelium during
2013 season, as Number of Infected Kernels at the inoculation point
(NIK), is lower than 10 for resistant, and between10 and 20 for susceptible
genotypes respectively. Under artificial inoculation, the fumonisin content ranged
from 90000 to 200000 �g/K for susceptible materials and < 30000 �g/Kg for
resistant genotypes. Preliminary data suggest that Canadian materials selected
for resistance/susceptibility to F. graminearum maintained the same trend also under F. verticilliodes
inoculation.
Acknowledgements
*Research
developed in the frame of CANADAIR Project, Ministero
delle Politiche Agricole Alimentari e Forestali (MiPAAF D.M. 254,
27240/7303/2011) coordinated by Dr. E. Lupotto (CRA-DPV). Thanks are due to Dr.
Linda Harris for material transfer.
Table 1: Maize genotypes under study
|
CRA-MAC Italy |
|
|
Lo 18 |
most resistant to F.
verticillioides |
|
Lo 43 |
most resistant to F.
verticillioides |
|
Lo 186 |
most susceptible to F.
verticillioides |
|
Lo 435 |
most susceptible to F.
verticillioides |
|
AAFC-ECORC
Canada |
|
|
RIL 19 |
most resistant to F.
graminearum |
|
RIL 77 |
most resistant to F.
graminearum |
|
RIL 226 |
most resistant to F.
graminearum |
|
RIL 278 |
most susceptible to F.
graminearum |
Figure 1:
Different inoculation assays
A B
Multi
Inoculation-Molecular analyses Single
Inoculation-Phenotyping
Please Note: Notes
submitted to the Maize Genetics Cooperation Newsletter may be cited only with
consent of authors.