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Identification of the anthracnose fungus of walnut ( Juglans spp.) and resistance evaluation through physiological responses of resistant vs. susceptible hosts
Author(s) -
Yang Hanbo,
Cao Guangli,
Jiang Shijiao,
Han Shan,
Yang Chunlin,
Wan Xueqin,
Zhang Fan,
Chen Lianghua,
Xiao Jiujin,
Zhu Peng,
Zhang Danju,
He Fang,
Xing Wenxi
Publication year - 2021
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/ppa.13354
Subject(s) - biology , juglans , polyphenol oxidase , inoculation , horticulture , catechol oxidase , chitinase , clone (java method) , botany , superoxide dismutase , point of delivery , sugar , peroxidase , food science , enzyme , dna , biochemistry , genetics
Walnut anthracnose is one of the most serious diseases of walnut globally. In this study, the pathogen was identified as Colletotrichum gloeosporioides by morphological and molecular approaches. Then, the resistance of 18 walnut genotypes was evaluated by field investigation as well as field and detached leaflet inoculation. A field inoculation assay was used as a benchmark for comparing field evaluation and the detached leaflet inoculation assay. Seven genotypes, Panhe1 and clones 71 and 200 of Juglans sigillata , Yanyuanzao and Qingxiang of J. regia , and Shujiang1 and Chuanzao1 of J. regia × J. sigillata , displayed high resistance in all assays, suggesting that they may be good candidates for further evaluation. Subsequently, two genotypes (Panhe1 with high resistance, and clone 199 with high susceptibility) were selected to analyse the different physiological responses between highly resistant and susceptible genotypes after inoculation. C. gloeosporioides infection induced the activities of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), and chitinase; they were all significantly increased in both Panhe1 and clone 199. However, the POD activity and its change rate in Panhe1 were significantly higher than those in clone 199. The change rates of PPO activity, and total phenol and proline content in Panhe1 were significantly higher than those in clone 199. Moreover, the change rates of SOD activity, malondialdehyde, and soluble sugar content in clone 199 were significantly higher than those in Panhe1. These findings not only enhance our understanding of the resistance of walnut to anthracnose, but also lay the foundation for breeding anthracnose‐resistant walnuts in the future.