Potentiation of defense-related gene expression by silicon increases wheat resistance to leaf blast

• Published in: Tropical plant pathology 2015-12, Vol.40 (6), p.394-400
• Main Authors: Cruz, Maria F. A., Debona, Daniel, Rios, Jonas A., Barros, Everaldo G., Rodrigues, Fabrício A.
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Life Sciences; Plant Pathology; Short Communication
• ISSN: 1983-2052; 1983-2052
• DOI: 10.1007/s40858-015-0051-7

It is well known that silicon (Si) increases the resistance of many plant species to several pathogens, including Pyricularia oryzae , the causal agent of blast on wheat, but the mechanisms underlying such resistance remain elusive. This study was carried out to investigate whether Si-mediated wheat resistance to blast could be linked to host defense responses at the histopathological level as well as with greater expression of defense-related genes. Wheat plants (cv. BR 18) were grown in hydroponic cultures containing 0 (−Si) or 2 mM (+Si) Si and were either non-inoculated or inoculated with P. oryzae . The foliar Si concentration was 0.4 and 4.5 dag/kg, and blast severity was 29.5 and 8.8 % for the −Si and +Si plants, respectively. Colonization of P. oryzae in leaf tissue for +Si plants was greatly limited and was associated with the deposition of phenolic compounds. The expression of all defense-related genes studied was significantly increased in response to P. oryzae infection. However, expression levels were 2- to 3-fold higher for the +Si plants relative to their −Si counterparts at 96 h after inoculation. This study provides further evidence that Si plays an active role in wheat resistance to leaf blast through the expression of some defense-related genes.