Alcaligenes faecalis—a maize endophytic bacterium to reduce Stewart wilt disease

บทคัดย่อ

Importance of the work: Alcaligenes faecalis can effectively reduce Stewart wilt
disease, one of the most important maize diseases.
Objectives: To evaluate the effect of A. faecalis on the inhibition of Stewart wilt disease
and growth enhancement of maize.
Materials and Methods: Three potential isolates of A. faecalis (JCB-1, JCJ-7 and MS-X)
were used to decrease the disease. The antagonistic activity, volatile organic compounds
(VOCs) and growth-promoting activities were evaluated in vitro. The effectiveness of
endophytes for stimulating maize growth was assessed using a seed germination test,
while their ability to reduce the disease was tested on seedlings. The responsiveness of
plant defense was detected by containing phenylalanine ammonia-lyase and polyphenol
oxidase (PPO) in seedlings. In addition, the chemical compounds of the bacterial
endophytes were identified using gas chromatography-mass spectrometry.
Results: All the tested endophytic isolates could fix nitrogen, solubilize phosphate and
produce indole. The A. faecalis MS-X isolate had the highest VOC activity (78.94%)
and efficacy in reducing disease severity (52.4%), while the most significant antibiosis
activity was produced by the isolate JCJ-7 (100%). In addition, the isolate MS-X had the
best capacity to induce PPO, along with excellent ability to reduce pathogen infection and
growth promoters, while JCB-1 effectively enhanced the germination of maize.
Main finding: A. faecalis had the potential to reduce Stewart wilt diseases by both
induction resistance and enhancing maize growth.