TITLE:
Quantitative Screening of Secretory Protein Genes in Candidatus Liberibacter Asiaticus
AUTHORS:
Binbin Li, Yi Yang, Zhiwen Luo, Zhixin Liu, Naitong Yu
KEYWORDS:
Candidatus Liberibacter Asiaticus, Secretory Protein, DNA Amount, RNA Transcription, Subcellular Localization
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.12,
November
19,
2018
ABSTRACT: Huanglongbing
(HLB) is the most destructive disease of citrus worldwide. The disease is
caused by Candidatus Liberibacter spp., which is vectored by the psyllids Diaphorina
citri Kuwayama and Trioza
erytreae.
Secretory proteins are important in bacterial pathogenesis and structure components.
Some of them are expressed at a high level. To obtain the highly-expressed
secretory protein genes (SPGs) for antiserum preparation, six candidate SPGs
were chosen from Candidatus Liberibacter asiaticus by bioinformatic analysis and were further tested by
qPCR and RT-qPCR methods, respectively. The result showed that two SPGs, 408 and pap (both
are Flp pilus assembly protein genes), have relative high amounts of DNA and
RNA transcripts of early HLB-infected green orange leaves. The 408 and pap genes
were further constructed into the plant expression vector pCAMBIA1300 (GV1300:
GFP) and expressed in tobacco leaf epidermal cells for subcellular localization
analysis. The transient expression results indicated that the 408 protein is
located in the nuclei and cytoplasm of tobacco leaf cells. However, the pap
protein is located in the cytoplasm of tobacco leaf cells, which may help the
pathogen invade into plant cells. This research is an important foundation for
the preparation of the antiserum against Candidatus Liberibacter asiaticus and the early detection of HLB disease.