Résumé
Leaf scald caused by Xanthomonas albilineans (Ashby) Downson is a destructive disease of sugarcane that can cause severe economic losses. During 2013–2017, 357 sugarcane leaf samples were collected from four provinces in China: 141 samples were taken from plants showing symptoms attributed to leaf scald and 216 were taken from asymptomatic plants. A previously described PCR protocol and PCR primers (XAF1/XAR1) targeting a putative ATP (adenosine triphosphate)-biding cassette (ABC) transporter gene (XALc_1791) were used to detect X. albilineans in these leaf samples. The pathogen was detected in 73% and 17% of symptomatic and asymptomatic leaf samples, respectively. The PCR-amplified fragments (608 bp) from 140 Xa-positive samples were cloned and sequenced. A total of 241 XALc gene sequences were obtained and compared to 13 sequences of X. albilineans isolates retrieved from GenBank. The isolates from China had 99.1–100% sequence identity with one another and 99.5–100% with four strains from the French West Indies (GPE PC73, GPE PC17, GPE PC86, and MTQ032) and one from Florida/USA (XaFLO7-1). Our findings show that X. albilineans causes leaf scald of sugarcane in Guangxi, Guangdong, Hainan, and Fujian provinces, suggesting that this disease could be a potential threat to the sugarcane industry in China.
•X. albilineans was detected in four major sugarcane-producing provinces in China.•X. albilineans was identified to infect sugarcane hybrids and wild germplasm clones.•Low genetic variation was found among the X. albilineans isolates from China.•Leaf scald is widespread in China and a potential threat to its sugarcane industry.