Martin Phillip L, Peter Kari A
Department of Plant Pathology and Environmental Microbiology, Fruit Research and Extension Center, The Pennsylvania State University, Biglerville, PA 17307.
Phytopathology. 2021 Feb;111(2):333-344. doi: 10.1094/PHYTO-05-20-0157-R. Epub 2021 Jan 13.
of the species complex is an important hemibiotrophic pathogen of vegetables and fruits in temperate regions worldwide. In apple, it is one of the primary species responsible for bitter rot disease. Understanding the disease cycle is complicated because many broadleaf plants can be hosts of By detecting and quantifying rain-splashed species complex conidia in more than 500 samples from heavily bitter-rot-infected apple orchards and nearby forested woodlots over two summers, we show that conidial quantities were higher in the woodlots than in the orchards. Testing of more than 1,000 surface-disinfected leaves of apple and 24 different forest plant species showed that overall was an abundant leaf endophyte, with high variation in leaf colonization area. Endophytic isolates from leaves were pathogenic on apples, and multilocus sequence analysis showed 100% identity between most isolates from leaves and diseased fruits. Apple leaves endophytically infected with were present in a conventionally managed orchard and abundant in an untreated orchard. These lines of evidence, in the context of previously published research, lead us to hypothesize that the main ecological role of is that of a leaf endophyte, which we present as a generalized infection cycle that provides an updated framework for its integrated management in agricultural systems.
该物种复合体是全球温带地区蔬菜和水果的一种重要半活体营养型病原菌。在苹果上，它是导致苦腐病的主要病原菌之一。由于许多阔叶植物都可能是其寄主，因此了解其病害循环很复杂。通过在两个夏天对来自苦腐病严重感染的苹果园和附近森林林地的500多个样本中的雨水飞溅的该物种复合体分生孢子进行检测和定量，我们发现林地中的分生孢子数量高于果园。对1000多片经过表面消毒的苹果叶和24种不同森林植物物种进行的测试表明，总体而言，它是一种丰富的叶内生菌，叶定殖面积差异很大。从叶片中分离出的内生菌对苹果具有致病性，多位点序列分析表明，大多数从叶片和患病果实中分离出的菌株之间具有100%的同一性。在一个传统管理的果园中存在内生感染该病菌的苹果叶，而在一个未处理的果园中则大量存在。结合之前发表的研究，这些证据使我们推测该病菌的主要生态作用是作为一种叶内生菌，我们提出了一个广义的感染循环，为其在农业系统中的综合管理提供了一个更新的框架。
