A natural fungicide identified in Zuccagnia punctata, a legume

Zuccagnia punctata is a species of legume native to Argentina and Chile. In a study published in Annals of Applied Biology, researchers found that the plant’s extracts and phenolic compounds have protective effects on corn against species of fungi.

• The researchers obtained the plant’s ethanolic leaf extract (TZP), its ethereal fraction (Eet), and its phenolic compounds: 2?,4??dihydroxychalcone (DC), 2?,4??dihydroxy?3??methoxychalcone (DMC), and 7?hydroxy?3?,4??dimethoxyflavone (HF) and evaluated these for their protective effects on corn seeds against species of Fusarium, particularly, Fusarium verticillioides.
• They found that DC had the lowest minimum inhibitory concentration (MIC) at only 25 to 50 mcg ML^-1. The MIC for the other extracts and compounds were 400 to 800 mcg mL^-1 (TZP), 50 to 100 mcg mL^-1 (Eet), 50 to 100 mcg mL^-1 (DMC), and 200 to 400 mcg mL^-1 (HF).
• The authors also incorporated suspensions of TZP, Eet, DC and DMC at MIC × 20 at rates of 1920, 240, 120 and 240 mg dry matter kg^-1 of grain respectively. This elongated the primary roots by 24 to 44 percent and increased the number of seminal roots by 44 to 50 percent. TZP, in particular, increased the number of secondary roots while HF was found to be phytotoxic.
• Furthermore, the suspensions suppressed the population of mycoflora at rates similar to what was observed with thiram + carbendazim?based fungicides. The improvements in root growth were attributed to this.
• Eet and its chalcones were also noted to have done a better job at reducing the severity of blight in corn seeds than thiram + carbendazim?based fungicides.

The researchers concluded that besides having protective effects on corn seeds against F. verticilloides and other seed-borne fungal pathogens, Eet and its chalcones could also improve the growth and performance of corn seedlings.

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Journal Reference:

Jiménez CM, Sgariglia M, Soberón J, Vattuone M, Sampietro D. EXTRACTS AND PHENOLIC COMPOUNDS FROM ZUCCAGNIA PUNCTATA AS FUNGICIDE SEED PROTECTANTS FOR CORN. Annals of Applied Biology. 2018;173(2):112–120. DOI: 10.1111/aab.12439