First Report of Pantoea anthophila Causing Soft Rot Disease in Clausena lansium (Wampee) in China

Abstract

Clausena lansium, also known as wampee (Clausena wampi), is a plant species native to China, Vietnam, the Philippines, Malaysia, and Indonesia, where it is widely cultivated, and also grown in India, Sri Lanka, Queensland, Florida, and Hawaii, but less frequently (3). The fruit can be consumed fresh or made into juice, jam, or succade. In summer to fall 2014, a soft rot disease was found in a wampee planting region in Yunan County, Guangdong Province, China. On Sept. 18, we collected diseased samples from a wampee orchard with about 20% disease incidence. The infected fruit initially showed pinpoint spots on the peel, water-soaked lesions, and light to dark brown discoloration. Spots expanded in 2 days, and tissues collapsed after 5 days. Severely affected fruit showed cracking or nonodorous decay. Five diseased samples were collected, and causal agents were isolated from symptomatic tissues 1 cm under the peel after surface sterilization in 0.3% NaOCl for 10 min and rinsing in sterile water three times. Tissues were placed on a Luria Bertani (LB) plate for culture. Ten representative isolates were selected for further characterization. No colony was isolated from healthy tissues. Colonies were round, smooth, with irregular edges, and produced a yellow pigment in culture. Biolog identification (Version 4.20.05) showed that all strains were gram negative, negative for indole production, and utilized glucose, maltose, trehalose, sucrose, D-lactose, and pectin but not sorbitol or gelatin. The isolates were identified as Pantoea agglomerans (SIM 0.69). Multilocus sequence analysis (MLSA) was conducted for rapid classification of the strains. Sequences of atpD, gyrB, infB, and rpoB were amplified using corresponding primers (2). All sequences of the 10 isolates were identical in each gene. BLASTn was performed, and maximum likelihood trees based on the concatenated nucleotide sequences of the four genes were constructed using MEGA6. Bootstrap values after 1,000 replicates were expressed as percentages. Results showed that the tested strain named CL1 was most homologous to P. anthophila, with 98% identity for atpD (KM521543), 100% for gyrB (KM521544), infB (KM521545), and rpoB (KM521546). The 16S rRNA sequence (KM521542) amplified by primers 27f and 1492r shared 99% identity with that of P. anthophila M19_2C (JN644500). P. anthophila was previously reclassified from P. agglomerans (3); therefore, we suggest naming this wampee pathogen P. anthophila. Subsequently, 10 wampee fruits were injected with 20 μl of bacterial suspension (1 × 108 CFU/ml) of strains CL1 and CL2, respectively, and another 10 were injected with 20 μl of LB medium as controls, all kept at 28°C for 4 days. Symptoms similar to those of natural infections were observed on inoculated fruits but not on the negative controls. Bacteria were isolated from diseased tissues and further identified as P. anthophila by gyrB sequencing. P. anthophila was reported to naturally infect balsam and marigold (1,2). To our knowledge, this is the first report of P. anthophila naturally causing soft rot disease and cracking on C. lansium (wampee). References: (1) C. Brady et al. Syst. Appl. Microbiol. 31:447, 2008. (2) C. Brady et al. Int. J. Syst. Evol. Microbiol. 59:2339, 2009. (3) J. Morton. Fruits of Warm Climates. Echo Point Books & Media, Miami, FL, 1987.

Characterization, Antimicrobial and Antioxidant evaluation of biofabricated silver nanoparticles from endophytic Pantoea anthophila

“…3.1 Endophytic Pantoea anthophila P. anthophila was previously reported in eucalyptus and maize and also found to cause infections in Impatiens balsamina, Tagetes erecta and Clausena lansium [28,29]. The multidimensional property of endophytes may produce stable nanoparticles with high medicinal potency, hence the extracelluar metabolite rich broth of P. anthophila are utilised for Pa-AgNPs synthesis.…”

Genomic characterization of Pantoea anthophila strain UI705 causing urinary tract infections in China

“…Wan et al reported the draft genome sequence of P. anthophila strain 11-2 isolated from hypersaline water from the lake on Laysan, Hawaii and numerous virulence-related components were identified based on bioinformatic analysis (Wan et al, 2015). Only one study by Zhou et al reported for the first time that P. anthophila naturally caused soft rot disease and cracking on C. lansium (Zhou et al, 2015), indicating that P. anthophila is pathogenic to plant.…”

“…Studies by Brady et al placed this strain into a separate cluster and proposed its current name as P. anthophila by using multilocus sequence analyses (MLSAs), amplified fragment length polymorphism (AFLP) analysis, and DNA-DNA hybridization in 2009 (Brady et al, 2009). Upon searching in PubMed, only one study reported that P. anthophila is pathogenic to plants and naturally causes soft rot disease and cracking on Clausena lansium (wampee) in China (Zhou et al, 2015).…”

Chemical Composition of Cuticle and Barrier Properties to Transpiration in the Fruit of Clausena lansium (Lour.) Skeels

“…Wampee is a perishable fruit, which is susceptible to mechanical damages, browning, and disease infection after harvest (Shao et al, 2020 ). Meanwhile, pathogen invasion as a factor-causing fruit softening and cracking has been a concern in wampee fruit production (Zhou et al, 2015 ). It has been widely reported that the chemical composition and the structural arrangements of the cell wall or cuticle, as well as the fruit surface properties, are pivotal in maintaining the fruit quality (Ríos et al, 2015 ; Winkler et al, 2020 ).…”