Peach gummosis caused by Lasiodiplodia theobromae is one of the most detrimental diseases to peaches in southern China. Reactive oxygen species (ROS) play major roles in plant-pathogen interactions, however, their roles in the pathogenesis of peach gummosis, especially shoot disease in perennials, are largely unknown. In this study, the effects of L. theobromae on ROS production-scavenging systems and on signalling transduction during L. theobromae-induced gummosis in current-year peach shoots were investigated. The infection by L. theobromae led to a ROS burst and activated the plant antioxidant enzyme-dependent scavenging system. With disease progression, the capacity of the plant antioxidant machinery declined, and allowed for ROS accumulation and eventual malondialdehyde production. As for the fungus L. theobromae, the transcripts of genes related to ROS production were significantly repressed, and concomitantly the expression of genes related to antioxidant systems and oxidative stress resistance was markedly upregulated, perhaps to alleviate oxidative stress for successful colonisation. Moreover, genes involved in phytohormones biosynthesis and pathogenesis-related proteins were all markedly promoted, which could contribute to the restriction of disease development in peach shoots. Overall, the results showed that the ROS production-scavenging system in P. persica might affect disease development during peach-L. theobromae interaction. Our findings lay the foundations for future in-depth investigations of the molecular mechanisms and regulatory networks underlying L. theobromae-mediated shoot diseases in terms of ROS production-scavenging systems.

由华北豆蔻（Lasiodiplodia theobromae）引起的桃牙龈病是对华南桃子最有害的疾病之一。活性氧（ROS）在植物与病原体的相互作用中起主要作用，但是，在桃胶病的发病机理中，尤其是多年生植物的芽病，其作用尚不清楚。在这项研究中，研究了Theobromae对当年桃芽中ROS产生-清除系统和在L.theobromae诱导的胶质病过程中信号转导的影响。Theobromae的感染导致ROS爆炸并激活了植物抗氧化酶相关的清除系统。随着疾病的进展，植物抗氧化剂机制的能力下降，并允许ROS积累并最终产生丙二醛。至于真菌L. theobromae，与ROS产生相关的基因的转录物被显着抑制，并且与抗氧化系统和氧化应激抗性相关的基因的表达也显着上调，也许是为了减轻氧化应激以成功定居。此外，与植物激素生物合成有关的基因和与病程相关的蛋白质都得到了显着促进，这可能有助于限制桃苗的病害发展。总体而言，结果表明，在桃-L。theobromae相互作用期间，百日草中的ROS产生清除系统可能影响疾病的发展。我们的发现为将来对L. theobromae的分子机制和调控网络的深入研究奠定了基础。ROS产生清除系统介导的芽病。