AUTHOR=Guo Chang-Fei , Kong Wei-Zhen , Mukangango Marguerite , Hu Yu-Wei , Liu Yu-Tao , Sang Wen , Qiu Bao-Li 

TITLE=Distribution and dynamic changes of Huanglongbing pathogen in its insect vector Diaphorina citri

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2024.1408362

DOI=10.3389/fcimb.2024.1408362

ISSN=2235-2988

ABSTRACT=<p>The Asian citrus psyllid (ACP) <italic>Diaphorina citri</italic> Kuwayama is the leading vector of <italic>Candidatus</italic> Liberibacter asiaticus (<italic>C</italic>Las), the causative agent of citrus Huanglongbing (HLB) disease. The distribution and dynamics of <italic>C</italic>Las within ACP are critical to understanding how the transmission, spread and infection of <italic>C</italic>Las occurs within its host vector in nature. In this study, the distribution and titer changes of <italic>C</italic>Las in various tissues of ACP 5<sup>th</sup> instar nymphs and adults were examined by <italic>fluorescence in situ hybridization</italic> (FISH) and real-time quantitative PCR (qPCR) techniques. Results demonstrated that 100% of ACP 5<sup>th</sup> instar nymphs and adults were infected with <italic>C</italic>Las following feeding on infected plants, and that <italic>C</italic>Las had widespread distribution in most of the tissues of ACP. The titers of <italic>C</italic>Las within the midgut, salivary glands and hemolymph tissues were the highest in both 5<sup>th</sup> instar nymphs and adults. When compared with adults, the titers of <italic>C</italic>Las in these three tissues of 5<sup>th</sup> instar nymphs were significantly higher, while in the mycetome, ovary and testes they were significantly lower than those of adults. FISH visualization further confirmed these findings. Dynamic analysis of <italic>C</italic>Las demonstrated that it was present across all the developmental ages of ACP adults. There was a discernible upward trend in the presence of <italic>C</italic>Las with advancing age in most tissues of ACP adults, including the midgut, hemolymph, salivary glands, foot, head, cuticula and muscle. Our findings have significant implications for the comprehensive understanding of the transmission, dissemination and infestation of <italic>C</italic>Las, which is of much importance for developing novel strategies to halt the spread of <italic>C</italic>Las, and therefore contribute to the efficient prevention and control of HLB.</p>