title: Wound-induced pectin methylesterases enhance banana (Musa spp. AAA) susceptibility to Fusarium oxysporum f. sp. cubense.
abstract: Recent studies suggest that plant pectin methylesterases (PMEs) are directly involved in plant defence besides their roles in plant development. However, the molecular mechanisms of PME action on pectins are not well understood. In order to understand how PMEs modify pectins during banana (Musa spp.)-Fusarium interaction, the expression and enzyme activities of PMEs in two banana cultivars, highly resistant or susceptible to Fusarium, were compared with each other. Furthermore, the spatial distribution of PMEs and their effect on pectin methylesterification of 10 individual homogalacturonan (HG) epitopes with different degrees of methylesterification (DMs) were also examined. The results showed that, before pathogen treatment, the resistant cultivar displayed higher PME activity than the susceptible cultivar, corresponding well to the lower level of pectin DM. A significant increase in PME expression and activity and a decrease in pectin DM were observed in the susceptible cultivar but not in the resistant cultivar when plants were wounded, which was necessary for successful infection. With the increase of PME in the wounded susceptible cultivar, the JIM5 antigen (low methyestrified HGs) increased. Forty-eight hours after pathogen infection, the PME activity and expression in the susceptible cultivar were higher than those in the resistant cultivar, while the DM was lower. In conclusion, the resistant and the susceptible cultivars differ significantly in their response to wounding. Increased PMEs and thereafter decreased DMs acompanied by increased low methylesterified HGs in the root vascular cylinder appear to play a key role in determination of banana susceptibility to Fusarium.
authors.affiliation: College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.forename: Shuang
authors.initials: S
authors.lastname: Jiang
authors.forename: Guimei
authors.initials: G
authors.lastname: Lin
authors.forename: Jianghua
authors.initials: J
authors.lastname: Cai
authors.forename: Xiaoxi
authors.initials: X
authors.lastname: Ye
authors.forename: Houbin
authors.initials: H
authors.lastname: Chen
authors.forename: Minhui
authors.initials: M
authors.lastname: Li
authors.forename: Huaping
authors.initials: H
authors.lastname: Li
authors.forename: Tomás
authors.initials: T
authors.lastname: Takác
authors.forename: Jozef
authors.initials: J
authors.lastname: Samaj
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Xu
mesh_terms: D002265:Carboxylic Ester Hydrolases / Q000096:biosynthesis*; D003124:Colorimetry; D060467:Disease Resistance / Q000502:physiology; D004790:Enzyme Induction; D005455:Fluorescent Antibody Technique; D005670:Fusarium / Q000378:metabolism*; D028521:Musa / Q000201:enzymology / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D016133:Polymerase Chain Reaction
chemical_list: D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase
keywords: Banana (Musa spp.); Fusarium wilt; degree of pectin methylesterification; host–; pathogen interaction; pectin methylesterases; wound induced.