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Kauralexins and zealexins accumulate in sub-tropical maize lines and play a role in seedling resistance to Fusarium verticillioides

Author:
Veenstra, Amy, Moola, Naadirah, Wighard, Sara, Korsman, Jeanne, Christensen, Shawn A., Rafudeen, M. Suhail, Murray, Shane L.
Source:
European journal of plant pathology 2019 v.153 no.1 pp. 223-237
ISSN:
0929-1873
Subject:
Fusarium verticillioides, biosynthesis, corn, crop yield, ear rot, fungi, genes, mutants, pathogens, phytoalexins, roots, seed inoculation, seedling diseases, seedlings, terpenoids, Africa
Abstract:
Maize is a socially and economically important crop in Africa (and worldwide) that is severely affected by many fungal pathogens. The pathogen Fusarium verticillioides can infect all maize tissue and causes Fusarium ear rot (FER), a disease that greatly reduces quantity and quality of annual maize yields. In response to fungal infection, maize produces kauralexins and zealexins, which are antimicrobial terpenoid phytoalexins that directly reduce the growth of many fungal pathogens including F. verticillioides. This research evaluates the induction of kauralexins and zealexins in F. verticillioides-inoculated sub-tropical maize lines. CML444 (moderately-resistant to FER) and CML144 (susceptible to FER) accumulated both phytoalexin types in seedling roots in response to seed inoculation with F. verticillioides. CML444 control roots also had higher kauralexin levels in comparison to CML144, suggesting that kauralexin accumulation may be primed for rapid up-regulation in CML444 following fungal infection. The an2 maize mutant, which displays reduced expression of the key kauralexin biosynthetic gene ZmAn2, accumulated decreased root levels of kauralexins and zealexins following F. verticillioides inoculation in comparison to wildtype line W22, confirming that both kauralexins and zealexins play a role in the resistance response to seedling disease caused by F. verticillioides.
Agid:
6310707