Transcriptome profiling analysis revealed co-regulation of multiple pathways in jujube during infection by 'Candidatus Phytoplasma ziziphi'.
Gene
; 665: 82-95, 2018 Jul 30.
Article
em En
| MEDLINE
| ID: mdl-29709641
ABSTRACT
BACKGROUND:
Jujube witches' broom (JWB), caused by a phytoplasma, devastates jujube tree (Ziziphus jujuba) growth and production in Asia. Although host responses to phytoplasmas are studied at the phenotypic, physiological, biochemical and molecular levels, it remains unclear how a host plant responds at the molecular level during the primary stage of infection.METHODS:
To understand the response of the jujube tree to JWB infection, leaves were sampled at different times during the phytoplasma infection. Transcriptomic analyses at six stages were performed to reveal how phytoplasma infection affects Chinese jujube gene expression through the determination of the key differentially expressed genes (DEGs), and their related pathways. Quantitative real-time PCR was applied to validate 10 differentially expressed genes at different JWB phytoplasma infection stages.RESULTS:
A total of 25,067 unigenes were mapped to jujube genome reference sequences. In the first infection stage (0-2â¯weeks after grafting (WAG), a total of 582 jujube genes were differentially regulated but no visible symptoms appeared. Quite a few DEGs related to abscisic acid (ABA) and cytokinin (CTK) were down-regulated, while some related to jasmonic acid (JA) and salicylic acid (SA) were up-regulated, Genes related to plant-pathogen interaction were also differentially expressed. In the second infection stage (37-39WAG), witches' broom symptoms were visible, and a total of 4373 DEGs were identified. Genes involved in biosynthesis and signal transduction of ABA, brassinosteroid (BR), CTK, ethylene (ET), and auxin (IAA), GA, JA and SA, plant-pathogen interaction, flavonoid biosynthesis genes were significantly regulated, suggesting that jujube trees activated defense factors related to SA, JA, ABA and secondary metabolites to defend against phytoplasma infection. By the third infection stage (48-52WAG), serious symptoms occurred and 3386 DEGs were identified. Most DEGs involved in biosynthesis and signal transduction of JA, SA and GA were up-regulated, while those relating to ABA were down-regulated. Genes involved in plant-pathogen interaction were up- or down-regulated, while phenylpropanoid and flavonoid biosynthesis genes were significantly up-regulated. Meanwhile, DEGs involved in photosynthesis, chlorophyll and peroxisome biosynthesis, and carbohydrate metabolism were down-regulated. These results suggested that phytoplasma infection had completely destroyed jujube trees' defense system and had disturbed chlorophyll synthesis and photosynthetic activity in the infected leaves at the late stage, resulting in yellow leaves and other JWB symptoms.DISCUSSION:
The results in this report suggested that phytohormone biosynthesis and signal transduction, photosynthesis, and secondary metabolism all played important roles in the battle between colonization and defense in the interaction between Ca. Phytoplasma ziziphi and jujube.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças das Plantas
/
Reguladores de Crescimento de Plantas
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Proteínas de Plantas
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Transdução de Sinais
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Germinação
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Regulação da Expressão Gênica de Plantas
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Ziziphus
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Phytoplasma
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Gene
Ano de publicação:
2018
Tipo de documento:
Article