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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Crop Improvement and Genetics Research » Research » Publications at this Location » Publication #332694
Title: PvPGIP2 accumulation in specific floral tissues, but not in the endosperm, limits Fusarium graminearum infection in wheat

Author
item TUNDO, SILVIO - University Of Tuscia
item JANNI, MICHELA - University Of Tuscia
item MOSCETTI, ILARIA - University Of Tuscia
item MANDALA, GIULIA - University Of Tuscia
item SAVATIN, DANIEL - University Of Rome
item Blechl, Ann
item FAVARON, FRANCESCO - Universita Di Padova
item D'OVIDIO, RENATO - University Of Tuscia

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2016
Publication Date: 10/15/2016
Citation: Tundo, S., Janni, M., Moscetti, I., Mandala, G., Savatin, D., Blechl, A.E., Favaron, F., D'Ovidio, R. 2016. PvPGIP2 accumulation in specific floral tissues, but not in the endosperm, limits Fusarium graminearum infection in wheat. Molecular Plant-Microbe Interactions. 29:815-821.

Interpretive Summary: Wheat is an important crop, providing dietary staples for much of the world’s population. One of the most destructive diseases of wheat is Fusarium Head Blight (FHB), which is caused by Fusaria fungi in years when flowering occurs during warm humid conditions. Wheat affected by FHB produces shriveled kernels that contain the mycotoxins produced by the fungus during its colonization of the wheat flower (head). We had previously used genetic engineering to show that introduction of a polygalacturonase inhibiting protein (PGIP) from green beans into all the tissues of wheat plants reduced FHB damage and mycotoxin accumulation in wheat grains. PGIPs are proteins that inhibit the activity of enzymes that the fungus secretes to dismantle the wheat cell walls during its invasion. In this report, we show that to be effective, the bean PGIP is needed only in the outer tissues of the flowers (lemma, palea and anthers) and in the connector between the flowers and the stem (rachis), but not in the seed itself. Thus, we can refine our biotechnology approach and reduce FHB symptoms and mycotoxins in wheat without introducing a bean protein into the grain we use as food.

Technical Abstract: Fusarium Head Blight (FHB) caused by Fusarium graminearum is one of the most destructive fungal diseases of wheat worldwide. The pathogen infects the spike at flowering time and causes severe yield losses, deterioration of grain quality, and accumulation of mycotoxins. The understanding of the precise means of pathogen entry and colonization of floral tissue is crucial to providing effective protection against FHB. Polygalacturonase inhibiting proteins (PGIPs) are cell wall proteins that inhibit the activity of polygalacturonases (PGs), a class of pectin-depolymerizing enzymes secreted by microbial pathogens, including Fusaria, and insects. The constitutive expression of a bean PGIP (PvPGIP2) limits FHB symptoms and reduces mycotoxin accumulation in wheat grain. To better understand which spike tissues play major roles in limiting F. graminearum infection, we explored the use of PvPGIP2 to defend specific spike tissues. We show here that the simultaneous expression of PvPGIP2 in lemma, palea, rachis and anthers reduced FHB symptoms caused by F. graminearum compared to symptoms in infected nontransgenic plants. However, the expression of PvPGIP2 only in the endosperm did not affect FHB symptom development, indicating that once the pathogen has reached the endosperm, inhibition of the pathogen’s PG activity is not effective in preventing further its spread.