title: Toxins produced by Valsa mali var. mali and their relationship with pathogenicity.
abstract: Valsa mali var. mali (Vmm), the causal agent of apple tree canker disease, produces various toxic compounds, including protocatechuic acid, p-hydroxybenzoic acid, p-hydroxyacetophenone, 3-(p-hydroxyphenyl)propanoic acid and phloroglucinol. Here, we examined the relationship between toxin production and the pathogenicity of Vmm strains and determined their bioactivities in several assays, for further elucidating the pathogenesis mechanisms of Vmm and for developing new procedures to control this disease. The toxins were quantified with the high performance liquid chromatography (HPLC) method, and the results showed that the strain with attenuated virulence produced low levels of toxins with only three to four kinds of compounds being detectable. In contrast, higher amounts of toxins were produced by the more aggressive strain, and all five compounds were detected. This indicated a significant correlation between the pathogenicity of Vmm strains and their ability to produce toxins. However, this correlation only existed in planta, but not in vitro. During the infection of Vmm, protocatechuic acid was first detected at three days post inoculation (dpi), and the others at seven or 11 dpi. In addition, all compounds produced noticeable symptoms on host plants at concentrations of 2.5 to 40 mmol/L, with protocatechuic acid being the most effective compound, whereas 3-(p-hydroxyphenyl)propanoic acid or p-hydroxybenzoic acid were the most active compounds on non-host plants.
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China. cxwang@qau.edu.cn.
authors.forename: Caixia
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China. 13864213246@163.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Li
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China. Baohuali@qau.edu.cn.
authors.forename: Baohua
authors.initials: B
authors.lastname: Li
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China. liguifangqingnong@163.com.
authors.forename: Guifang
authors.initials: G
authors.lastname: Li
authors.affiliation: Key Lab of Integrated Crop Pest Management of Shandong Province, College of Agronomy and Plant Protection, Qingdao Agricultural University, Qingdao 266109, China. xldong@qau.edu.cn.
authors.forename: Xiangli
authors.initials: X
authors.lastname: Dong
authors.affiliation: College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. gpwang@mail.hzau.edu.cn.
authors.forename: Guoping
authors.initials: G
authors.lastname: Wang
authors.affiliation: College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China. zhangqingminghf@163.com.
authors.forename: Qingming
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D001203:Ascomycota / Q000378:metabolism / Q000472:pathogenicity*; D001937:Brassica / Q000187:drug effects / Q000254:growth & development; D018553:Cucumis sativus / Q000187:drug effects / Q000254:growth & development; D018525:Germination / Q000187:drug effects; D018551:Solanum lycopersicum / Q000187:drug effects / Q000254:growth & development; D027845:Malus / Q000187:drug effects / Q000382:microbiology*; D009183:Mycotoxins / Q000032:analysis* / Q000633:toxicity; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D014026:Nicotiana / Q000187:drug effects; D014774:Virulence
chemical_list: D009183:Mycotoxins