Improvement of Hanseniaspora uvarum biocontrol activity against gray mold by the addition of ammonium molybdate and the possible mechanisms involved

Abstract

The efficacy of Hanseniaspora uvarum against gray mold by adding ammonium molybdate (NH 4–Mo) and the mode of actions were evaluated. The results showed that H. uvarum at 1 × 10 6 CFU ml −1 plus 1 mmol l −1 NH 4–Mo greatly reduced gray mold in grape fruits. NH 4–Mo at concentrations of 1, 5, 10 and 15 mmol l −1 significantly inhibited spore germination and mycelium growth of Botrytis cinerea. Population growth of H. uvarum was markedly inhibited by NH 4–Mo at 5 mmol l −1 in vitro and not affected by addition of NH 4–Mo at 1 and 5 mmol l −1 in wounds combination of NH 4–Mo and H. uvarum induced higher activities of peroxidase (POD), polyphenoloxidase (PPO), phenylalanine ammonialyase (PAL), superoxide dismutase (SOD), catalase (CAT) and β-1,3-Glucanase than individual application of H. uvarum or NH 4–Mo. The enhancement of disease control may be directly because of the inhibitory effects of NH 4–Mo on spore germination and mycelial growth of B. cinerea in vitro, and indirectly because of the induced defense reactions by NH 4–Mo in grape berries.