Pseudomonas syringae causes bacterial blight (BB) disease worldwide on economically important fruit and vegetable crops including field pea (Pisum sativum L.). The two pathovars responsible for BB in field pea are Pseudomonas syringae pathovar pisi (Psp) and syringae (Pss). In the field, both pathovars cause indistinguishable symptoms on field pea and require laboratory diagnosis to determine the causal pathovar. To aid in-field and laboratory diagnosis, accurate, and robust loop-mediated isothermal amplification (LAMP) assays for Psp and Pss were developed. The assays were able to detect Psp or Pss on live or heat-killed bacterial cells, plant exudates, seeds, and DNA extracts with no inhibitory effects. The two specific LAMP assays developed detected Psp and Pss accurately in less than 20 min and no cross-reaction was observed with 18 strains of closely related species of Pseudomonas syringae. Compared to the conventional PCR assays, the two LAMP assays were equally specific but have advantages of producing quicker and visual live results, enabling early detection and differentiation of Psp and Pss. Our results suggested a potential use of LAMP assays for laboratory testing and can be applied for in-field surveys.

High-quality complete genomes of five Xylella fastidiosa strains were assembled by combining Nanopore and Illumina sequencing data. Among these, International Collection of Micro-organisms from Plants (ICMP) 8731, ICMP 8742 and ICMP 8745 belong to subspecies fastidiosa while ICMP 8739 and ICMP 8740 were determined as subspecies multiplex . The strains were further classified into sequence types.