The Potency Purple Sweet Potato (Ipomoea batatas) Leaf Extract as Biofungicide for Controlling Fusarium Rot on Chili -

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The Potency Purple Sweet Potato (Ipomoea batatas) Leaf Extract as Biofungicide for Controlling Fusarium Rot on Chili

Purple sweet potato (Ipomoea batatas L.) is potentially utilized as biofungicide to control Fusarium fruit rot disease in chili. Purple sweet potato contains secondary metabolites, mainly the active compounds in the form of flavonoids, which has been previously revealed to perform antifungal activity. The ethanol-extracted purple sweet potato leaves extracts against Fusarium sp. with 40% (w/v) for in vitro assay and showed 76.6% inhibitory ability of the leaves extract against the growth of Fusarium sp.  Its antifungal test was conducted using preventive and curative test for in vivo assay. Purple sweet potato leaves extract with 40% concentration can reduce the intensity of Fusarium fruit rot disease and potentially utilized as biofungicide.

Material and Methods

Purple Sweet Potato Leaves Extraction

Samples of purple sweet potato leaves used in this study were macerated with ethanol 70% solvent in a 1:10 ratio at room temperature for 5 days. Next, the macerated samples were filtered and evaporated in a rotary evaporator IKA RV6 at 60 ºC to evaporate, resulting in a concentrated extract. Then, the concentrated extract was weighed to measure the extract yield of maceration. Extracts concentration of purple sweet potato leaves were made by dissolving previously concentrated extract (40%) with DMSO 10% solvent.

In Vitro Assay of Purple Sweet Potato Leaf Extract Against Fusarium sp.

In vitro assays of ethanol extracted purple sweet potato leaves on the growth of Fusarium sp. were performed on PDA mediums aseptically. Each extract was mixed with liquid PDA to form the medium with a specific sweet potato extract concentration of 40%. Furthermore, isolates of Fusarium sp. in 5 mm diameter were grown on all test media. As a negative control, Fusarium sp. isolates were grown on a non-extract-added PDA medium, which was without the addition of purple sweet potato leaves extract. For positive control, isolates of Fusarium sp. were also grown on a non-extract added PDA medium mixed with a Propineb 70% fungicide at 0.2% concentration (w/v).  Each in vitro test treatment was repeated 5 times.

In vivo inhibition Assay

In vivo inhibition assays of purple sweet potato leaf extract with 40% concentration were conducted in curative and preventive tests. A curative test was performed to determine the ability of purple sweet potato leaf extract to suppress the incidence of chili rot disease after Fusarium sp. attack. Curative treatment was performed after the first symptoms arose and seven days after the fruit rot. Rot chili fruits were soaked in purple sweet potato leaf extract suspension for 10 minutes, dried, placed on the tray, and subsequently incubated for 7 days. As a negative control, chilis were incubated with-out soaking in the purple sweet potato leaf extract. A preventive test was performed to determine the potency of purple sweet potato leaf extract to prevent Fusarium infection in chili. The purple sweet potato leaf extract was applied before rot chili disease symptoms appeared.

Results

In vitro assays of purple sweet potato leaves ethanol extract on the growth of Fusarium sp. application of purple sweet potato leaves extracts at 40% concentration was observed to perform a very strong inhibitory ability. Observations of in vitro test results on growing media indicated the addition of leaves extracts at 40% concentration to be more effective in inhibiting the growth of Fusarium sp., resulting in the highest inhibition percentage at 76.6%.

In general, the uses of chemical fungicides had been stated to affect the conditions of soil, water, treated agriculture products, and human users of these fungicides, hence causing further problems such as unbalanced ecosystems. Therefore, the uses of biofungicide had been stated to act as an alternative treatment in controlling diseases in plants. Purple sweet potato leaves can be used as an antifungal because they contain anthocyanin compounds, which are secondary metabolites of flavonoid and polyphenol groups. As an antifungal, flavonoid and phenol can damage pathogenic cell membranes, resulting in changes in cell growth or deaths of fungal cells. These compounds can also desaturate pathogenic cell proteins and shrink cell walls to then lyse fungal cell walls.

 

Reference:

Saputri, D.D. and Utami, A.W.A., 2020. The Potency Of Purple Sweet Potato (Ipomoea Batatas) Leaf Extract As Biofungicide For Controlling Fusarium Rot On Chili. Journal Of Agriculture And Applied Biology, 1(1), pp.1-8.