Department of Crop and Soil Sciences, University of Georgia, Tifton Campus, Tifton, GA 31793, U.S.A.
Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, 35020 Legnaro, Italy.
Plant Dis. 2020 Oct;104(10):2598-2605. doi: 10.1094/PDIS-11-19-2477-RE. Epub 2020 Aug 14.
() is an emerging insect-vectored, xylem-limited bacterium that can cause disease on several economically important fruit and tree crops including almond, blueberry, citrus, grapevine, peach, and pecan. On blueberry, causes bacterial leaf scorch (BLS), which is prevalent in the southeastern United States. This disease, previously reported to be caused by subsp. (), can result in rapid plant decline and death of southern highbush (SHB) blueberry cultivars. In 2017, a survey of blueberry plantings in southern Georgia (U.S.A.) confirmed the presence of -infected plants in eight of nine sites examined, and seven isolates were cultured from infected plants. Genetic characterization of these isolates through single-locus and multilocus sequence analysis revealed that three isolates from two sites belonged to subsp. (), with significant similarity to isolates from grapevine. After these three isolates were artificially inoculated onto greenhouse-grown SHB blueberries (cv. 'Rebel'), symptoms typical of BLS developed, and infection was confirmed through genetic characterization and reisolation of the bacterium to fulfill Koch's postulates. Because all previously reported isolates from blueberry have been characterized as , this is the first time that isolation of has been reported from naturally infected blueberry plantings. The potential impact of isolates on disease management in blueberry requires further exploration. Furthermore, given that isolates from both and were obtained within a single naturally infected blueberry planting, blueberry in southern Georgia may provide opportunities for intersubspecific recombination between and isolates.
()是一种新兴的昆虫媒介、木质部局限细菌，可引起杏仁、蓝莓、柑橘、葡萄、桃和山核桃等几种重要经济作物的疾病。在蓝莓上，引起细菌性叶斑病（BLS），该病普遍存在于美国东南部。这种疾病以前被认为是由 亚种 ()引起的，可导致南方高丛蓝莓（SHB）品种迅速衰退和死亡。2017 年，对美国佐治亚州南部蓝莓种植园的调查证实，在所检查的 9 个地点中有 8 个存在感染的植物，从感染的植物中培养了 7 个分离株。通过单基因座和多位点序列分析对这些分离株的遗传特征进行分析表明，来自两个地点的三个分离株属于 亚种 ()，与葡萄藤上的分离株具有显著相似性。这三个分离株被人工接种到温室种植的 SHB 蓝莓（cv. 'Rebel'）上后，出现了典型的 BLS 症状，并通过遗传特征和对细菌的重新分离证实了 感染，满足科赫假设。由于以前从蓝莓中分离出的所有 菌株都被鉴定为 ，这是首次从自然感染的蓝莓种植园中分离出 。需要进一步探索 分离株对蓝莓疾病管理的潜在影响。此外，由于 和 分离株都来自单一的自然感染蓝莓种植园，佐治亚州南部的蓝莓可能为 和 分离株之间的种间重组提供机会。
