Study on Interactions between the Major Apple Valsa Canker Pathogen Valsa mali and Its Biocontrol Agent Saccharothrix yanglingensis Hhs.015 Using RT-qPCR.
The mechanism of biocontrol agent Saccharothrix yanglingensis Hhs.015 action against Valsa mali, a major apple Valsa canker pathogen, was examined using a novel, sensitive (minimum detection limit 100 pg/μL) and reliably RT-qPCR technique. Prior to lesion formation, total concentration of V. mali in the bark showed a significant decrease (p<0.05) after 24 h of Hhs.015 treatment. This was more pronounced at 48 and 96 h post treatment. After lesion formation, levels of V. mali remained constant at the boundary between infected and uninfected bark tissues, although the relative expansion rate of the lesion was significantly reduced (p<0.05). Gene expression levels of endo-polygalacturonase, a marker for fungal pathogenicity, were sharply reduced while host induced resistance callose synthase levels increased significantly (p<0.05) at the boundary bark at 9 d after Hhs.015 treatment. The results showed that biocontrol agent Hhs.015 prevented infection of V. mali by inhibiting pathogen growth, down-regulating pathogenicity factor expression and inducing a high level of host resistance.
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China.|College of Life Science, Northwest A&F University, Yangling, Shaanxi, China.
Dongying
D
Fan
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China.|College of Life Science, Northwest A&F University, Yangling, Shaanxi, China.
Yanfang
Y
Li
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China.|College of Life Science, Northwest A&F University, Yangling, Shaanxi, China.
Lingyun
L
Zhao
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China.|College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
Zhengpeng
Z
Li
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China.|College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
Lili
L
Huang
State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, China.|College of Life Science, Northwest A&F University, Yangling, Shaanxi, China.
Xia
X
Yan
D000192:Actinomycetales / Q000502:physiology*; D001203:Ascomycota / Q000502:physiology*; D027845:Malus / Q000378:metabolism / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D011096:Polygalacturonase / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D011096:Polygalacturonase