Integrated physiological and transcriptomic analysis reveals molecular distinctions between Huanglongbing- and Zn/Mn deficiency-induced chlorosis in citrus
- 1Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Engineering Research Center of Biological Control, Ministry of Education/State Key Laboratory of Green Pesticide, College of Plant Protection, South China Agricultural University, Guangzhou, 515000 Guangdong China
- 2National Center for International Collaboration Research on Precision Agricultural Aviation Pesticide Spraying Technology, Guangdong Engineering Technology Research Center of Smart Agriculture, College of Artificial Intelligence, South China Agricultural University, Guangzhou, 510642 China
Abstract
Background: Citrus Huanglongbing (HLB) and zinc/manganese (Zn/Mn) deficiency induce similar chlorosis in young leaves, complicating field diagnosis. Despite visual similarities, the molecular mechanisms distinguishing these disorders remain unclear. This study employed integrated transcriptomic and physiological analyses to contrast HLB-specific responses with nutrient deficiency in Citrus sinensis (sweet orange) and Citrus reticulata 'Orah', aiming to identify the abiotic cause of chlorosis and clarify the underlying molecular divergence.
Result: “Candidatus Liberibacter asiaticus” (CLas)-infected leaves showed significant downregulation of photosynthesis-related genes but upregulated starch/sucrose metabolism and phenylpropanoid biosynthesis, divergent from Zn/Mn-deficient leaves. Intriguingly, photosynthetic efficiency was independent of chlorosis severity. Starch accumulation was markedly higher and more consistent in HLB than in nutrient deficiency, serving as a predominant diagnostic marker. Flavonoid biosynthesis was significantly enhanced under both stresses, but the transcriptional induction was more pronounced and conserved across leaf positions in HLB. Additionally, plant-pathogen interaction pathways were activated exclusively in CLas-infected leaves, highlighting biotic stress-specific responses.
Conclusion: We propose a practical diagnostic matrix—pairing starch assays with molecular signatures of biotic defense—to differentiate HLB from nutrient deficiency. Our comparative analysis reveals HLB establishes a unique "defense-priority" metabolic state, offering both actionable management tools and a novel conceptual framework for understanding its pathology.
Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s12870-026-09447-0.
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BibTeX
@article{cui2026integrated,
title = {{Integrated physiological and transcriptomic analysis reveals molecular distinctions between Huanglongbing- and Zn/Mn deficiency-induced chlorosis in citrus}},
author = {Xiaoqing Cui and Sumiao Zhang and Lu Chen and Zheng Zheng and Xiaoling Deng and Xiaoling Deng and Wen Sang and Meirong Xu},
journal = {BMC Plant Biology},
year = {2026},
month = aug,
doi = {10.1186/s12870-026-09447-0},
url = {https://doi.org/10.1186/s12870-026-09447-0},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Integrated physiological and transcriptomic analysis reveals molecular distinctions between Huanglongbing- and Zn/Mn deficiency-induced chlorosis in citrus
AU - Xiaoqing Cui
AU - Sumiao Zhang
AU - Lu Chen
AU - Zheng Zheng
AU - Xiaoling Deng
AU - Xiaoling Deng
AU - Wen Sang
AU - Meirong Xu
PY - 2026
DA - 2026/08/08
JO - BMC Plant Biology
DO - 10.1186/s12870-026-09447-0
UR - https://doi.org/10.1186/s12870-026-09447-0
AB - Background: Citrus Huanglongbing (HLB) and zinc/manganese (Zn/Mn) deficiency induce similar chlorosis in young leaves, complicating field diagnosis. Despite visual similarities, the molecular mechanisms distinguishing these disorders remain unclear. This study employed integrated transcriptomic and physiological analyses to contrast HLB-specific responses with nutrient deficiency in Citrus sinensis (sweet orange) and Citrus reticulata 'Orah', aiming to identify the abiotic cause of chlorosis and clarify the underlying molecular divergence. Result: “Candidatus Liberibacter asiaticus” (CLas)-infected leaves showed significant downregulation of photosynthesis-related genes but upregulated starch/sucrose metabolism and phenylpropanoid biosynthesis, divergent from Zn/Mn-deficient leaves. Intriguingly, photosynthetic efficiency was independent of chlorosis severity. Starch accumulation was markedly higher and more consistent in HLB than in nutrient deficiency, serving as a predominant diagnostic marker. Flavonoid biosynthesis was significantly enhanced under both stresses, but the transcriptional induction was more pronounced and conserved across leaf positions in HLB. Additionally, plant-pathogen interaction pathways were activated exclusively in CLas-infected leaves, highlighting biotic stress-specific responses. Conclusion: We propose a practical diagnostic matrix—pairing starch assays with molecular signatures of biotic defense—to differentiate HLB from nutrient deficiency. Our comparative analysis reveals HLB establishes a unique "defense-priority" metabolic state, offering both actionable management tools and a novel conceptual framework for understanding its pathology. Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s12870-026-09447-0.
SN - 1471-2229
ER -