Xylella fastidiosa (Xf) 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, Xf causes bacterial leaf scorch (BLS), which is prevalent in the southeastern United States. This disease, previously reported to be caused by Xf subsp. multiplex (Xfm), 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 Xf-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 Xf subsp. fastidiosa (Xff), 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 Xff infection was confirmed through genetic characterization and reisolation of the bacterium to fulfill Koch’s postulates. Because all previously reported Xf isolates from blueberry have been characterized as Xfm, this is the first time that isolation of Xff has been reported from naturally infected blueberry plantings. The potential impact of Xff isolates on disease management in blueberry requires further exploration. Furthermore, given that isolates from both Xfm and Xff were obtained within a single naturally infected blueberry planting, blueberry in southern Georgia may provide opportunities for intersubspecific recombination between Xff and Xfm isolates.

fastylosa（Xf）是一种新兴的以昆虫为载体的，木质部受限的细菌，可在几种经济上重要的水果和树木作物（包括杏仁，蓝莓，柑橘，葡萄，桃和山核桃）上引起疾病。在蓝莓上，Xf会引起细菌的叶子灼焦（BLS），这在美国东南部很普遍。该疾病先前报道是由Xf亚种引起的。多重（Xfm），可导致植物迅速衰退并导致南部高灌木（SHB）蓝莓品种死亡。2017年，一项对美国乔治亚州南部蓝莓种植的调查证实了Xf的存在在检查的9个位点中的8个位点中，有8个被感染的植物，从被感染的植物中培养了7个分离株。通过单基因座和多基因座序列分析对这些分离物进行遗传表征，发现来自两个位点的三个分离物属于Xf亚种。fastidiosa（Xff），与葡萄树的分离物具有显着相似性。在将这三种分离株人工接种到温室种植的SHB蓝莓（cv。“ Rebel”）上之后，出现了BLS的典型症状，并且通过遗传鉴定和重新分离细菌来证实Xff感染，从而满足了Koch的假设。因为先前报道的所有蓝莓Xf分离株都被表征为Xfm，这是首次报道从自然感染的蓝莓种植中分离出Xff。Xff分离物对蓝莓疾病管理的潜在影响需要进一步探索。此外，考虑到Xfm和Xff的分离株都是在一次自然感染的蓝莓种植中获得的，佐治亚州南部的蓝莓可能为Xff和Xfm分离株之间的种间重组提供了机会。