Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State, MS, U.S.A.; and Pest Integrated Management Key Laboratory of China Tobacco, Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao 266101, China.
Delta Research and Extension Center, Mississippi State University, Stoneville, MS, U.S.A.
Plant Dis. 2019 Mar;103(3):422-429. doi: 10.1094/PDIS-07-18-1150-RE. Epub 2019 Jan 11.
Bacterial blight, historically a seed-borne disease of cotton (Gossypium hirsutum) is caused by Xanthomonas citri pv. malvacearum, resulted in significant economic losses prior to development of resistant varieties and implementation of acid-delinting of planting seed. Periodic outbreaks have been associated with seed since the early twentieth century; of note, the disease has experienced a resurgence since 2011. Effective management of bacterial blight is dependent on accurate diagnosis and detection of the pathogen. Currently, detection of X. citri pv. malvacearum is performed by time-consuming microbiological methods. In this study, a novel and sensitive TaqMan-based qPCR protocol was developed to test for X. citri pv. malvacearum in cotton plant tissue. The primers developed are specific to five races of X. citri pv. malvacearum, but not to other Xanthomonas species or cotton-associated nonpathogenic bacteria. The efficiency of this assay was evaluated on artificially inoculated cotton leaves and seed, on naturally infected cotton leaves, and on bolls and seed originating from bacterial blight symptomatic bolls. The protocol's efficiency from artificially inoculated plant tissue was 10 copies g and 37 copies from 1 g seed for leaves and seed, respectively. In addition, X. citri pv. malvacearum was detected from 94% of the seed samples originating from blight symptomatic bolls. The qPCR protocol provides a rapid and accurate method for diagnosis and detection of bacterial blight and offers a tool for monitoring X. citri pv. malvacearum and potentially reducing its spread in seed.
细菌性疫病，历史上是棉花（Gossypium hirsutum）的种子传播疾病，由黄单胞菌野油菜致病变种（Xanthomonas citri pv. malvacearum）引起，在培育出抗性品种和实施种子脱绒酸处理之前，导致了重大的经济损失。自 20 世纪初以来，种子就与周期性爆发有关；值得注意的是，自 2011 年以来，该疾病再次爆发。细菌性疫病的有效管理依赖于对病原体的准确诊断和检测。目前，对黄单胞菌野油菜致病变种的检测是通过耗时的微生物方法进行的。在这项研究中，开发了一种新的、基于 TaqMan 的敏感 qPCR 方案，用于测试棉花植物组织中的黄单胞菌野油菜致病变种。开发的引物特异性针对黄单胞菌野油菜致病变种的五个菌株，但不能针对其他黄单胞菌物种或与棉花相关的非致病性细菌。该测定法的效率在人工接种的棉花叶片和种子、自然感染的棉花叶片以及源自细菌性疫病病铃的棉铃和种子上进行了评估。该方案从人工接种的植物组织中的效率为 10 拷贝 g，从叶片和种子的 1 g 种子中分别为 37 拷贝。此外，从源自疫病病铃的 94%的种子样本中检测到了黄单胞菌野油菜致病变种。qPCR 方案为细菌性疫病的诊断和检测提供了一种快速、准确的方法，并为监测黄单胞菌野油菜致病变种和潜在减少其在种子中的传播提供了一种工具。
