Production of the biocontrol agents Meyerozyma guilliermondii and Pichia kudriavzevii using a low-cost carbon source and their ability to control mango disease in field trials

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发表日期：

2025年6月28日

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Chutima Kaewkrajay,
Orapan Thongprasom,
Thitiya Loylom,
Tida Dethoup

摘要

The goal of this work was to use the antagonistic marine yeasts Meyerozyma guilliermondii ARU3232-1 and Pichia kudriavzevii DMKUJC44-2 to control anthracnose and stem-end rot diseases of the mango cultivar Nam Dok Mai Si Thong, under field conditions. The appropriate carbon source for yeast cell growth was initially screened from broken-milled rice hydrolysate, distillery slop, and sugarcane molasses. Among these carbon sources, sugarcane molasses was promising in supporting the growth of both yeast strains. Statistical screening of nutrient components for yeast growth using sugarcane molasses as a carbon source was carried out using a Plackett–Burman design. Each affecting factor was optimized using the one-factor-at-a-time (OFAT) method. The optimized medium for the cultivation of M. guilliermondii ARU3232-1 was 60 g L⁻¹ sugarcane molasses, 5 g L⁻¹ NH₄Cl, 5 g L⁻¹ KH₂PO₄, 10 g L⁻¹ peptone, and 5 g L⁻¹ yeast extract. In comparison, for P. kudriavzevii DMKUJC44-2, it was 80 g L⁻¹ sugarcane molasses, 20 g L⁻¹ peptone, 5 g L⁻¹ KH₂PO₄, 5 g L⁻¹ yeast extract, and 5 g L⁻¹ malt extract. The fresh cells of both yeast strains were sprayed on mango trees three times during the flowering, fruit set, and fruit-developing stages and twice during the flowering and fruit-setting stages. The results showed that spraying M. guilliermondii ARU3232-1 at a concentration of 10⁸ cells mL⁻¹ and P. kudriavzevii DMKUJC44-2 at a same concentration, mixed with 1% carboxymethyl cellulose (CMC), three times, most effectively reduced mango disease severity by 85.77 ± 2.05% and 82.87 ± 3.16%, respectively. While the chemical fungicide Prochloraz decreased disease severity by 87.89 ± 8.71%. It suggests that both yeast strains act as effective biocontrol agents.