Open AccessWitches’ Broom Disease of Lime Contributes to Phytoplasma Epidemics and Attracts Insect Vectors
Author(s) -
Ali M. AlSubhi,
Abdullah M. Al-Sadi,
Rashid Al-Yahyai,
Yazhou Chen,
Thomas C. Mathers,
Zigmunds Orlovskis,
Gabriele Moro,
Sam T. Mugford,
Khalid Al-Hashmi,
Saskia A. Hogenhout
Publication year - 2021
Publication title -
plant disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.663
H-Index - 108
eISSN - 1943-7692
pISSN - 0191-2917
DOI - 10.1094/pdis-10-20-2112-re
Subject(s) - phytoplasma , broom , biology , leafhopper , lime , insect , vector (molecular biology) , botany , virology , gene , polymerase chain reaction , genetics , ecology , restriction fragment length polymorphism , paleontology , hemiptera , recombinant dna
An insect-transmitted phytoplasma causing Witches’ Broom Disease of Lime (WBDL) is responsible for the drastic decline in lime production in several countries. However, it is unclear how WBDL phytoplasma (WBDLp) induces witches’ broom symptoms and if these symptoms contribute to the spread of phytoplasma. Here we show that the gene encoding SAP11 of WBDLp (SAP11 WBDL ) is present in all WBDLp isolates collected from diseased trees. SAP11 WBDL interacts with acid lime (Citrus aurantifolia) TCP transcription factors, specifically members of the TB1/CYC class that have a role in suppressing axillary branching in plants. Sampling of WBDLp-infected lime trees revealed that WBDLp titers and SAP11 WBDL expression levels were higher in symptomatic leaves compared with asymptomatic sections of the same trees. Moreover, the witches’ brooms were found to attract the vector leafhopper. Defense genes that have a role in plant defense responses to bacteria and insects are more downregulated in witches’ brooms compared with asymptomatic sections of trees. These findings suggest that witches’ broom-affected parts of the trees contribute to WBDL epidemics by supporting higher phytoplasma titers and attracting insect vectors.