Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy

Huanglongbing (HLB), which is mainly associated with “Candidatus Liberibacter asiaticus” (CLas), is currently threatening citrus production around the world. This destructive century-old disease results in callose deposition in phloem plasmodesmata and starch overaccumulation in leaf chloroplasts. H...

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Main Authors: Ruixuan Pan, Yanling Chen, Xiaoling Deng, Meirong Xu
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2021-01-01
Series:Horticultural Plant Journal
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S246801412030128X
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author Ruixuan Pan
Yanling Chen
Xiaoling Deng
Meirong Xu
author_facet Ruixuan Pan
Yanling Chen
Xiaoling Deng
Meirong Xu
author_sort Ruixuan Pan
collection DOAJ
description Huanglongbing (HLB), which is mainly associated with “Candidatus Liberibacter asiaticus” (CLas), is currently threatening citrus production around the world. This destructive century-old disease results in callose deposition in phloem plasmodesmata and starch overaccumulation in leaf chloroplasts. Heat treatment with high humidity has proven to be effective in eliminating the CLas titers in potted citrus trees. This study explored the curative mechanisms and impact of heat treatment (from 32 to 48 °C with 75% ± 5% relative humidity, 14 h in light and 10 h in dark for four days) on mandarin trees (Citrus reticulata Blanco) that were severely infected by CLas using Solexa/Illumina's digital gene expression (DGE) profiling. A total of 838 differentially expressed genes (DEGs) were identified, of which 510 were downregulated. Protein-protein interaction analysis of the DEGs indicated that the thermotherapy of HLB trees downregulated the circadian clock related genes in chloroplasts and upregulated the RNA-editing process in the mitochondria, characterized by 141 genes encoding pentatricopeptide repeat-containing proteins (PPR) being all upregulated. Furthermore, the expression of phenylpropanoid and flavonoid biosynthesis genes, and auxin-induced genes were suppressed. The defense response pathway of the thermotherapy treated diseased trees was apparently disrupted, as indicated by the downregulation of LRR receptor-like serine/threonine-protein kinase FLS2 gene. This study improves our understanding of the curative mechanisms of heat treatment on HLB trees and CLas biological regulation. Importantly, this provides new insights on the involvement of RNA modification by PPR genes and changes in the circadian clock after the heat stress treatment of CLas-infected citrus.
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spelling doaj.art-7dc1e755fe8e46f5bf0f5e73c69b2ed02024-04-16T13:59:32ZengKeAi Communications Co., Ltd.Horticultural Plant Journal2468-01412021-01-0171112Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to ThermotherapyRuixuan Pan0Yanling Chen1Xiaoling Deng2Meirong Xu3Laboratory of Citrus Huanglongbing Research, Guangdong Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, ChinaLaboratory of Citrus Huanglongbing Research, Guangdong Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, ChinaCorresponding authors. Tel: +86 20 38297040, +86 20 38297495.; Laboratory of Citrus Huanglongbing Research, Guangdong Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, ChinaCorresponding authors. Tel: +86 20 38297040, +86 20 38297495.; Laboratory of Citrus Huanglongbing Research, Guangdong Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, ChinaHuanglongbing (HLB), which is mainly associated with “Candidatus Liberibacter asiaticus” (CLas), is currently threatening citrus production around the world. This destructive century-old disease results in callose deposition in phloem plasmodesmata and starch overaccumulation in leaf chloroplasts. Heat treatment with high humidity has proven to be effective in eliminating the CLas titers in potted citrus trees. This study explored the curative mechanisms and impact of heat treatment (from 32 to 48 °C with 75% ± 5% relative humidity, 14 h in light and 10 h in dark for four days) on mandarin trees (Citrus reticulata Blanco) that were severely infected by CLas using Solexa/Illumina's digital gene expression (DGE) profiling. A total of 838 differentially expressed genes (DEGs) were identified, of which 510 were downregulated. Protein-protein interaction analysis of the DEGs indicated that the thermotherapy of HLB trees downregulated the circadian clock related genes in chloroplasts and upregulated the RNA-editing process in the mitochondria, characterized by 141 genes encoding pentatricopeptide repeat-containing proteins (PPR) being all upregulated. Furthermore, the expression of phenylpropanoid and flavonoid biosynthesis genes, and auxin-induced genes were suppressed. The defense response pathway of the thermotherapy treated diseased trees was apparently disrupted, as indicated by the downregulation of LRR receptor-like serine/threonine-protein kinase FLS2 gene. This study improves our understanding of the curative mechanisms of heat treatment on HLB trees and CLas biological regulation. Importantly, this provides new insights on the involvement of RNA modification by PPR genes and changes in the circadian clock after the heat stress treatment of CLas-infected citrus.http://www.sciencedirect.com/science/article/pii/S246801412030128XCitrushuanglongbingheattranscriptomdifferentially expressed genes
spellingShingle Ruixuan Pan
Yanling Chen
Xiaoling Deng
Meirong Xu
Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy
Horticultural Plant Journal
Citrus
huanglongbing
heat
transcriptom
differentially expressed genes
title Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy
title_full Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy
title_fullStr Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy
title_full_unstemmed Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy
title_short Digital Gene Expression Analysis of Huanglongbing Affected Mandarins (Citrus reticulata Blanco) In Response to Thermotherapy
title_sort digital gene expression analysis of huanglongbing affected mandarins citrus reticulata blanco in response to thermotherapy
topic Citrus
huanglongbing
heat
transcriptom
differentially expressed genes
url http://www.sciencedirect.com/science/article/pii/S246801412030128X
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AT xiaolingdeng digitalgeneexpressionanalysisofhuanglongbingaffectedmandarinscitrusreticulatablancoinresponsetothermotherapy
AT meirongxu digitalgeneexpressionanalysisofhuanglongbingaffectedmandarinscitrusreticulatablancoinresponsetothermotherapy