Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: June 18, 1997
Publication Date: N/A
Technical Abstract: Polymerase chain reaction (PCR) and isolation on semi-selective medium (XAS) were used to study the distribution of the leaf scald bacterium, Xathomonas albilineans (Xa), in infected sugarcane stalks. Eleven pairs of symptomatic vs. asymptomatic stalks were collected from the field between late November and early December from Xa-infected stools of three varieties [LCP 82-89 (5 pairs), CP 65-357(1 pair), and CP 74-383(5 pairs)]. Sap was collected from 17 to 25 internodes of each stalk and examined for Xa by both methods. Based on combined results of the two methods, it was concluded that: 1) Xa was detected in every internode in symptomatic stalks of all three varieties with the exception of the top-most 3 to 5 internodes where Xa was occasionally undetectable; 2) Distribution of Xa was sporadic among internodes of asymptomatic stalks with the exception that Xa was detected in every internode of one asymptomatic stalk of variety CP 74-383; 3) For the 463 internodes tested, results were matched by both methods in 395 (85.3%) internodes, of which 264 tested positive. However, 39 internodes (8.4%) tested positive only by PCR but not by isolation, while 28 internodes (6%) tested positive only by isolation but not by PCR.