title: In vitro study of the growth, development and pathogenicity responses of Fusarium oxysporum to phthalic acid, an autotoxin from Lanzhou lily.
abstract: Continuous monoculture of Lanzhou lily (Lilium davidii var. unicolor Cotton) results in frequent incidence of fusarium wilt caused by Fusarium oxysporum. Phthalic acid (PA), a principal autotoxin from root exudates of Lanzhou lily, is involved in soil sickness by inducing autotoxicity. The aim of this study was to evaluate the direct allelopathic effects of PA on the growth, development and pathogenicity of F. oxysporum in vitro based on an ecologically relevant soil concentration. The results showed that PA slightly but not significantly inhibited the colony growth (mycelial growth) and fungal biomass of F. oxysporum at low concentrations ranging from 0.05 to 0.5 mM, and significantly inhibited the colony growth at the highest concentration (1 mM). None of the PA concentrations tested significantly inhibited the conidial germination and sporulation of F. oxysporum in liquid medium. However, mycotoxin (fusaric acid) yield and pathogenesis-related hydrolytic enzyme (protease, pectinase, cellulase, and amylase) activities were significantly stimulated in liquid cultures of F. oxysporum containing PA at ≥ 0.25 mM. We conclude that PA at a soil level (i.e. 0.25 mM) is involved in plant-pathogen allelopathy as a stimulator of mycotoxin production and hydrolytic enzyme activities in F. oxysporum, which is possibly one of the mechanisms responsible for promoting the wilt disease of lily.
authors.affiliation: Gaolan Station of Agricultural and Ecological Experiment, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China.
authors.forename: Zhijiang
authors.initials: Z
authors.lastname: Wu
authors.forename: Liu
authors.initials: L
authors.lastname: Yang
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Wang
authors.forename: Yubao
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qianhan
authors.initials: Q
authors.lastname: Shang
authors.forename: Le
authors.initials: L
authors.lastname: Wang
authors.forename: Qin
authors.initials: Q
authors.lastname: Ren
authors.forename: Zhongkui
authors.initials: Z
authors.lastname: Xie
mesh_terms: D005670:Fusarium / Q000187:drug effects / Q000254:growth & development* / Q000472:pathogenicity*; D027762:Lilium / Q000737:chemistry* / Q000378:metabolism / Q000382:microbiology; D010795:Phthalic Acids / Q000378:metabolism / Q000494:pharmacology*; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D013172:Spores, Fungal / Q000187:drug effects* / Q000254:growth & development* / Q000472:pathogenicity; D014774:Virulence / Q000187:drug effects
chemical_list: D010795:Phthalic Acids; C032279:phthalic acid