Report of a Quarantine Sugarcane Leaf Scald Disease in Guangxi, China

摘要

In 2016, sugarcane plants were observed in Beihai, Laibin, and Baise in Guangxi province, China for leaf scaled disease. To identify the pathogen, DNA was extracted and PCR was performed with specific primer XAF1/XAR1 for Xanthomonas allbilineans on 62 suspected leaf scald samples collected from Beihai, Laibin and Baise. The PCR results showed that about 600 bp PCR products were obtained from all the samples. Twenty-one PCR products were randomly selected for sequencing. Subsequent sequence analysis revealed that all nucleotide sequences of this study were identical and shared 100% sequence similarity with the nucleotide sequence from the raxB1 gene of X. albilineans (GenBank accession no. FP565176), and were clustered with X. albilineans sequences in one branch of a phylogenetic tree. Field surveys showed that sugarcane cultivar ‘Guitang46’ and ‘Guitang06-2081’ were highly susceptible with disease incidences of 18-100%. Leaf scald can cause huge losses in sugarcane yield and sugar content because severely infected plants show wilting, abnormal development of side shoots, and white-striped leaves on side shoots. Leaf scald disease can be easily transmitted by vegetative propagation in sugarcane, so it is necessary to take appropriate prevention and management measures to prevent the spread of leaf scald from onset.