Identification and characterization ofXanthomonas albilineanscausing sugarcane leaf scald in China using multilocus sequence analysis

Abstract

Xanthomonas albilineans is the causal agent of leaf scald, a disease that can cause considerable damage to sugarcane industries. This study analysed the phylogenetic relationship of 14 samples of X. albilineans from China and 13 reference strains retrieved from the GenBank database by multilocus sequence analysis (MLSA). To reach this goal, five housekeeping genes of X. albilineans were amplified from diseased leaves and sequenced: gyrB, abc, rpoD, atpD and glnA. Based on the concatenated sequence of these genes (4473 nt), the 14 samples of X. albilineans from China had 99.9–100% sequence identity with one another and with five strains of the pathogen from the French West Indies and the USA (Florida). The 27 samples or strains of X. albilineans were distributed in two distinct clades in the MLSA‐based phylogenetic tree. Clade 1 was formed by four strains of the pathogen from Fiji, Papua New Guinea and the USA. All the other strains from worldwide locations, including the 14 samples from China, were grouped in clade 2. This latter clade included all strains of the pathogen that were associated with outbreaks of leaf scald that have occurred over the last two decades, especially in the Caribbean islands and the USA. The very low diversity of X. albilineans in four Chinese provinces suggests recent spread of a single strain (from genetic group PFGE‐B) of the leaf scald pathogen within China.

Complete Genome Sequence Reveals Evolutionary and Comparative Genomic Features of Xanthomonas albilineans Causing Sugarcane Leaf Scald

“…These six strains also clustered together in a phylogenetic tree based on the core-genome sequence of 16 strains of the pathogen. These results are congruent with those obtained in a previous study based on an ABC transporter gene (XALc_1791) and five housekeeping genes [13], suggesting a common evolutionary route for these six strains of X. albilineans. We hypothesized that the occurrence of X. albilineans in mainland China is linked to former frequent introductions of sugarcane germplasm and cultivars from Taiwan and foreign countries such as the USA, India, and Australia.…”

“…In recent years, leaf scald of sugarcane has been reported with increasing frequency in five sugarcane-growing regions of China by PCR-based detection [12,17,18]. Very low genetic diversity was found among strains of X. albilineans from China, based on sequence analysis of an ABC transporter gene (XALc_1791) and MLSA, suggesting recent spread in this country of a single strain (from genetic group PFGE-B) of the leaf scald pathogen [12,13]. Since 2009, 15 genome sequences of X. albilineans strains from 10 worldwide geographical locations have been deposited in GenBank with complete or scaffold sequences.…”

“…However, our previous studies showed that the genetic diversity of X. albilineans from China is very low. MLSA analysis of 14 strains from this country revealed that they belong to the PFGE group B, based on five housekeeping genes [12,13]. With the advent of sequencing technologies, genome sequence data can help to resolve the phylogeny among the strains of X. albilineans by considering mutation and recombination at the whole-genome level [14].…”

Genome-wide identification and characterization of DCL, AGO and RDR gene families in Saccharum spontaneum

“…Additionally, leaf scald caused by Xanthomonas albilineans is one of three main sugarcane bacterial diseases, and is responsible for significant loss in cane yield and juice quality 33 . Leaf scald exists in some sugarcane-producing areas in China, where it represents a potential threat to the sugar industry 34 , 35 . In this study we identified and classified protein members of the DCL, AGO and RDR gene families in the S. spontaneum genome, and analyzed the functions of these genes to understand their roles in responses to polyethylene glycol (PEG)-induced dehydration stress and X. albilineans infection.…”

Comparative Transcriptome Profiling of Resistant and Susceptible Sugarcane Cultivars in Response to Infection by Xanthomonas albilineans

“…Unlike abiotic stresses, microbes causing biotic stresses are complex living entities that have the potential to penetrate and thrive inside the plant. Among these, the bacterium Xanthomonas albilineans causes a major sugarcane disease called leaf scald [7]. This disease results in significant reductions in sugarcane yield and juice quality in susceptible cultivars, preventing their commercial use [8,9].…”