Abstract：The aim of the present study was to investigate the effect of plant growth-promoting rhizo‐
bacteria (PGPR) Bacillus amyloliquefacien AW3 strain on disease resistance in Pinus koraiensis in‐
fected with Fusarium oxysporum. P. koraiensis saplings were inoculated with AW3 using fermenta‐
tion liquor under greenhouse conditions. Relative control factors of root rot such as soluble protein,
soluble sugar, phenylalanine ammonia lyase (PAL), catalase (CAT), superoxide dismutase (SOD) and
disease resistance related genes were determined. The results indicated that the inhibitory effect of
AW3 on root rot in P. koraiensis was remarkably high (79.3%). AW3 induced a rapid generation of
cell defense in P. koraiensis after inoculation of AW3 in P. koraiensis. The relative staining intensity
of reactive oxygen species (ROS) was 2.57 and cell membrane permeability was 2.98 times that of thecontrol group, and the difference was significant (P<0.05). The content of soluble sugar and suluble
protein of P. koraiensis saplings increased significantly (P<0.05). AW3 significantly increased the ac‐
tivity of SOD, POD and reduced CAT. AW3 also induced transcription of jasmonic acid (JA), sali‐
cylic acid (SA), and genes involved in auxin signaling. In summary, AW3 induced disease resistance
against F. oxysporum infection in P. koraiensis and reduced occurrence of the disease through a com‐
bined action of defense-related enzymes and resistance genes. AW3 is a very effective bacterial
strain that can be used to control root rot in P. koraiensis, however further studies on the development
of biologics using AW3 and its field applications are advocated.
