title: Comparative Transcriptomic Analysis Reveals That Ethylene/H2O2-Mediated Hypersensitive Response and Programmed Cell Death Determine the Compatible Interaction of Sand Pear andAlternaria alternata.
abstract: A major restriction on sand pear (Pyrus pyrifolia) production is black spot disease caused by the necrotrophic fungusAlternaria alternata. However, the pear response mechanism toA. alternatais unknown at the molecular level. Here, host responses of a resistant cultivar Cuiguan (CG) and a susceptible cultivar Sucui1 (SC1) toA. alternatainfection were investigated. We found that the primary necrotic lesion formed at 1 dpi and the expansion of lesions was aggressive in SC1. Data from transcriptomic profiles using RNA-Seq technology identified a large number of differentially expressed genes (DEGs) between CG and SC1 in the early phase ofA. alternatainfection. K-mean cluster and Mapman analysis revealed that genes involved in ethylene (ET) biosynthesis and ET signaling pathway, such as ACS, ACOs, and ERFs, and in hypersensitive response (HR) and programmed cell death (PCD) were significantly enriched and up-regulated in the susceptible cultivar SC1. Conversely, genes involved in response to hydrogen peroxide and superoxide were differentially up-regulated in the resistant cultivar CG after inoculation with the fungus. Furthermore, ET levels were highly accumulated in SC1, but not in CG. Higher activities of detoxifying enzymes such as catalases were detected in CG. Our results demonstrate that the ET-/H2O2-mediated PCD and detoxifying processes play a vital role in the interaction of pear andA. alternata.
authors.affiliation: Institute of Horticulture, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement Nanjing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Institute of Horticulture, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement Nanjing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Lin
authors.affiliation: Institute of Horticulture, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement Nanjing, China.
authors.forename: Youhong
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Plant Sciences, University of California at DavisDavis, CA, USA; Crops Pathology and Genetics Research Unit, United States Department of Agriculture, Agricultural Research ServiceDavis, CA, USA.
authors.forename: Cai-Zhong
authors.initials: CZ
authors.lastname: Jiang
keywords: Alternaria alternata (Fr.) Keissler; antioxidant enzyme; ethylene; hydrogen peroxide; hypersensitive response; programmed cell death; sand pear