TITLE:
Characterization and in Plant Detection of Bacteria That Cause Bacterial Panicle Blight of Rice
AUTHORS:
Temesgen Mulaw, Yeshi Wamishe, Yulin Jia
KEYWORDS:
Burkholderia glumae, Bacterial Panicle Blight (BPB), Hypersensitive Reactions, In-Plant Detection
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.4,
March
14,
2018
ABSTRACT: Burkholderia
glumae presumably induces a grain rot symptom of rice that
is threatening to rice production in most rice producing states of the USA. The
present study was to identify the causal agent of bacteria panicle blight (BPB), virulence based on hypersensitive reactions and
distribution of the pathogen within a plant. 178 rice panicles samples were
analyzed with semi-selective media (CCNT), polymerase chain reaction (PCR) with
bacterial DNA gyrase (gyrB) specific markers, and hypersensitive reactions on
tobacco leaves. A total of 73 samples out of 178 produced a yellow bacterial
colony with similar morphology on CCNT medium suggesting they were bacterial
panicle diseases. However, with PCR
reactions we only determined that 45 of 73 were due to B. glumae, and the causal agent for the remaining samples was
undetermined. Within the 45 samples, 31 highly, 6 moderately, and 5 weakly
virulent isolates were grouped based on lesion sizes of the hypersensitive
reactions. Pathogenicity variability among the 45 B. glumae detected suggests that different degrees of pathogenicity
exist. To determine the existence of bacteria in different plant tissues,
naturally infected plant parts were examined with CCNT media and PCR analysis. B. glumae was again isolated from seeds
followed by stems and sheaths from light yellow pigmented CCNT media. In
contrast, roots and leaves show no visible yellow pigment on CCNT. Consistent
PCR products were produced from the stem, sheath, and seed, but not from the
root and leaves. These findings suggest that B. glumae is distributed in the stem, sheath, and seed, and not in
the leaf and root. Together this study demonstrated the usefulness of
artificial culture media, tobacco reactions, and DNA test with PCR for
characterization of BPB, and distribution of bacteria in plants. These findings
will help to understand the mechanism of bacteria translocation in plants.