Background Tea, which is produced from new shoots of existing tea plants (Camellia sinensis), is one of the most popular, non-alcoholic, healthy beverages worldwide. Colletotrichum camelliae is one of the dominant fungal pathogens of tea. The interaction of C. camelliae with tea could be a useful pathosystem to elucidate various aspects of woody, medicinal plant-fungal interactions. Currently, many studies characterizing resistance or virulence and aggressiveness use lesion size at the infection sites on the leaves to quantify the growth of the pathogen. However, this method does not offer the sensitivity needed for the robust quantification of small changes in aggressiveness or the accurate quantification of pathogen growth at the early stages of infection. Results A quantitative real-time polymerase chain reaction (qRT-PCR) assay was developed for the quantification of C. camelliae growth on tea plant. This method was based on the comparison of fungal DNA in relation to plant biomass. This assay was used to investigate the phenotypes of tea plant cultivars in response to C. camelliae infection. Two cultivars, Zhongcha 108 (ZC108) and Longjing 43 (LJ43), were tested with this method. ZC108 was previously reported as an anthracnose-resistant cultivar against C. camelliae, while LJ43 was susceptible. The traditional lesion measurement method showed that both cultivars were susceptible to a virulent strain of C. camelliae, while the qRT-PCR approach indicated that very little fungal growth occurred in the anthracnose-resistant cultivar ZC108. The observed results in this study were consistent with previously published research. In addition, the DNA-based real-time PCR method was applied for analysis of pathogenic differences in general C. camelliae isolates and among several Colletotrichum spp that infect tea. Conclusions This study showed that the DNA-based qRT-PCR technique is rapid, highly sensitive and easily applicable for routine experiments and could be used in screening for resistant tea plant cultivars or to identify differences in pathogen aggressiveness within and among Colletotrichum species.

中文翻译：

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开发基于 DNA 的实时 PCR 测定法，用于定量茶（Camellia sinensis）中茶花炭疽菌的生长。

背景 茶是由现有茶树（Camellia sinensis）的新芽制成的，是全球最受欢迎的无酒精健康饮料之一。茶花炭疽菌是茶叶的主要真菌病原体之一。茶花与茶的相互作用可能是一个有用的病理系统来阐明木本、药用植物-真菌相互作用的各个方面。目前，许多表征抗性或毒力和侵袭性的研究使用叶片感染部位的病变大小来量化病原体的生长。然而，这种方法不能提供对攻击性的微小变化进行稳健量化或在感染早期阶段准确量化病原体生长所需的灵敏度。结果 开发了一种定量实时聚合酶链反应 (qRT-PCR) 测定法，用于定量茶树上茶花的生长。该方法基于真菌 DNA 与植物生物量的比较。该测定法用于研究茶树栽培品种对 C. camelliae 感染的反应。采用该方法对中茶108（ZC108）和龙井43（LJ43）两个品种进行了试验。ZC108 曾被报道为抗炭疽病的品种，可抗茶花，而 LJ43 则易感。传统的病斑测量方法表明，两个品种都对山茶花的毒株敏感，而 qRT-PCR 方法表明，抗炭疽病品种 ZC108 的真菌生长非常少。本研究中观察到的结果与先前发表的研究一致。此外，基于 DNA 的实时 PCR 方法被应用于分析一般茶花分离株和几种感染茶的炭疽菌属之间的致病差异。结论 本研究表明，基于 DNA 的 qRT-PCR 技术快速、灵敏度高且易于用于常规实验，可用于筛选抗性茶树品种或鉴定炭疽菌种内和间的病原体侵袭性差异。