Abstract
Developing kernels of maize with contrasting levels of resistance to Fusarium ear rot were
inoculated with Fusarium verticillioides. Selected defense systems were investigated using realtime
reverse transcription-polymerase chain reaction to monitor the expression of pathogenesisrelated
(PR) genes (PR1, PR5, PRm3, PRm6) and genes protective from oxidative stress
(peroxidase, catalase, superoxide dismutase and ascorbate peroxidase) at 72 hours post inoculation.
In this respect, the hydrogen peroxide and malondialdehyde contents were studied to evaluate the
oxidation level. The study was also extended to the analysis of the ascorbate-glutathione cycle and
catalase, superoxide dismutase, and cytosolic and wall peroxidases enzymes. Higher levels of gene
expression, enzymatic activities and antioxidant metabolites were observed in uninoculated kernels
of resistant lines, conferring a major readiness to the pathogen attack. After inoculation, the level of
gene induction was stronger in susceptible lines, although their enzymatic activity was higher in the
resistant lines. The susceptible genotypes, therefore, respond specifically to pathogen inoculation,
while resistant genotypes have already high levels of defense-related transcripts before infection,
which provide a basal defense system. In the susceptible maize, the presence of oxidative stress due
to its incapacity to remove ROS might help to explain its susceptibility to F. verticillioides. These
results support our previous findings of a basal defense response provided by maize genotypes
resistant against F. verticillioides infection, both in kernels and seedlings. Our data provide an
important basis for further investigation of defense gene functions in developing kernels in order to
improve resistance to fungal pathogens. Maize genotypes with overexpressed resistance traits could
be profitably utilized in breeding programs focused on resistance to pathogens and grain safety.
Lingua originale | English |
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Titolo della pubblicazione ospite | Proceedings of the Joint Congress SIBV-SIGA |
Pagine | 246 |
Numero di pagine | 1 |
Stato di pubblicazione | Pubblicato - 2015 |
Evento | Joint Congress SIBV-SIGA - Milano Durata: 8 set 2015 → 11 set 2015 |
Convegno
Convegno | Joint Congress SIBV-SIGA |
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Città | Milano |
Periodo | 8/9/15 → 11/9/15 |
Keywords
- Fusarium verticilliodes
- Zea mays
- defense systems
- resistance