Shiga-toxigenic Escherichia coli (STEC) is often transmitted into food via fresh produce plants, where it can cause disease. To identify early interaction factors for STEC on spinach, a high-throughput positive-selection system was used. A bacterial artificial chromosome (BAC) clone library for isolate Sakai was screened in four successive rounds of short-term (2 h) interaction with spinach roots, and enriched loci identified by microarray. A Bayesian hierarchical model produced 115 CDS credible candidates, comprising seven contiguous genomic regions. Of the two candidate regions selected for functional assessment, the pO157 plasmid-encoded type two secretion system (T2SS) promoted interactions, while a chaperone-usher fimbrial gene cluster (loc6) did not. The T2SS promoted bacterial binding to spinach and appeared to involve the EtpD secretin protein. Furthermore, the T2SS genes, etpD and etpC, were expressed at a plant-relevant temperature of 18 °C, and etpD was expressed in planta by E. coli Sakai on spinach plants.

产志贺毒素大肠杆菌(STEC) 通常通过新鲜农产品植物传播到食物中，在那里它会引起疾病。为了确定菠菜上 STEC 的早期相互作用因素，使用了高通量正选择系统。在连续四轮与菠菜根的短期（2 小时）相互作用中筛选了分离 Sakai 的细菌人工染色体 (BAC) 克隆文库，并通过微阵列确定了富集的位点。贝叶斯分层模型产生了 115 个 CDS 可信候选者，包括七个连续的基因组区域。在选择用于功能评估的两个候选区域中，pO157 质粒编码的二型分泌系统 (T2SS) 促进相互作用，而伴侣引导菌毛基因簇 ( loc6） 没有。T2SS 促进细菌与菠菜的结合，并且似乎涉及 EtpD 分泌蛋白。此外，T2SS基因，etpD和ETPC，分别以18℃的植物相关的温度表示，和etpD表达在植物中由大肠杆菌酒井对菠菜植物。