title: Identification of a xyloglucan-specific endo-(1-4)-beta-D-glucanase inhibitor protein from apple (Malus × domestica Borkh.) as a potential defense gene against Botryosphaeria dothidea.
abstract: Botryosphaeria dothidea is the causal agent of apple ring rot which is a highly destructive apple disease in China. Here, a putative xyloglucan-specific endo-(1-4)-beta-d-glucanase inhibitor protein from Malus×domestica (designated as MdXEGIP1) was found to be involved in defense against B. dothidea infection. MdXEGIP1 shares high amino acid sequence identity with other apple XEGIPs, but exhibited significantly different responses to B. dothidea infection. Quantitative real-time PCR revealed that MdXEGIP1 expression was significantly induced in shoot bark of apple plant by B. dothidea and showed different expression pattern in resistant and susceptible apple cultivars. In resistant cultivar, MdXEGIP1 expression was elevated with larger amplitude than that in susceptible cultivar after B. dothidea infection. MdXEGIP1 expression was also significantly enhanced by treatment with exogenous methyl jasmonate and salicylic acid in apple plantlets. Further investigation revealed that recombinant MdXEGIP1 has significant inhibitor activity to XEGs from family 12 and 74 of glycoside hydrolase. More importantly, recombinant MdXEGIP1 inhibited crude enzyme solution of XEG from B. dothidea, suggesting that MdXEGIP1 might protect apple plant from B. dothidea infection by inhibiting XEG activity. Taken together, the results indicated that MdXEGIP1 is a potential defense gene against B. dothidea in apple.
authors.affiliation: College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China; College of Life Sciences, Key Laboratory of Plant Biotechnology of Shandong Province, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Suhua
authors.initials: S
authors.lastname: Bai
authors.affiliation: College of Life Sciences, Key Laboratory of Plant Biotechnology of Shandong Province, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Chaohua
authors.initials: C
authors.lastname: Dong
authors.affiliation: College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.affiliation: College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China.
authors.forename: Yugang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Horticulture, Qingdao Agricultural University, Qingdao 266109, China. Electronic address: hydai@qau.edu.cn.
authors.forename: Hongyi
authors.initials: H
authors.lastname: Dai
mesh_terms: D001203:Ascomycota / Q000472:pathogenicity*; D018506:Gene Expression Regulation, Plant; D005936:Glucans / Q000378:metabolism; D027845:Malus / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014990:Xylans / Q000378:metabolism
chemical_list: D005936:Glucans; D010940:Plant Proteins; D014990:Xylans; C029353:xyloglucan
keywords: Botryosphaeria dothidea; Gene expression; Malus×domestica; Pathogen defense; Xyloglucan-specific endo-(1-4)-beta-d-glucanase inhibitor protein