Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Al Khod 123, Oman.
John Innes Centre, Department of Crop Genetics, Norwich NR4 7UH, United Kingdom.
Plant Dis. 2021 Sep;105(9):2637-2648. doi: 10.1094/PDIS-10-20-2112-RE. Epub 2021 Oct 24.
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 of WBDLp () is present in all WBDLp isolates collected from diseased trees. interacts with acid lime () 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 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.
一种由昆虫传播的植原体导致了酸橙的扫帚病（WBDL），这是几个国家酸橙产量急剧下降的原因。然而，目前尚不清楚 WBDL 植原体（WBDLp）如何引起扫帚病症状，以及这些症状是否有助于植原体的传播。在这里，我们表明，WBDLp 中编码（）的基因存在于从患病树上收集的所有 WBDLp 分离株中。与酸橙（）TCP 转录因子相互作用，特别是在植物腋芽分支抑制中起作用的 TB1/CYC 类成员。对感染 WBDLp 的酸橙树进行采样表明，与同一树上无症状部位相比，有症状叶片中的 WBDLp 滴度和表达水平更高。此外，发现扫帚病吸引了媒介叶蝉。与树木无症状部位相比，在植物对细菌和昆虫防御反应中起作用的防御基因在扫帚病中下调更多。这些发现表明，受扫帚病影响的树木部分通过支持更高的植原体滴度和吸引昆虫媒介来促进 WBDL 流行。
