Lachancea thermotolerans acts as a resistance inducer in soybean infected with Meloidogyne incognita

Abstract

The worldwide interest in sustainable agriculture has contributed to the development of alternative methods for the control of plant pests and diseases. This study aimed to assess the efficiency of Lachancea thermotolerans CCMA 0763 and its metabolites in controlling Meloidogyne incognita in soybean and their effects on plant defense enzymes and glyceollin synthesis. The following treatments were applied as foliar spray 4 days before nematode inoculation: fermentation broth, broth filtrate, yeast cells, sugarcane juice, acibenzolar-S-methyl (ASM). An inoculated untreated control and an absolute control were also included. The same treatments were used in the glyceollin assay. For analysis of resistance induction, the treatments were fermentation broth, broth filtrate, yeast cells, ASM, and water (control). Fermentation broth and yeast cells reduced total nematode number, population density and reproduction factor. Yeast-based treatments and ASM enhanced glyceollin synthesis compared with sugarcane juice and water. Peroxidase activity was highest at 4 and 10 days after treatment in plants treated with yeast-based treatmentss. Broth filtrate and yeast cells increased polyphenol oxidase activity at 4 days after treatment. Phenylalanine ammonia-lyase and glucanase activities were not influenced by treatment. L. thermotolerans stimulated phytoalexin synthesis in soybean cotyledons and defense enzyme activity in soybean roots, showing potential as a biopesticide.