Overexpressing a NPR1-like gene from Citrus paradisi enhanced Huanglongbing resistance in C. sinensis

• Published in: Plant cell reports 2021-03, Vol.40 (3), p.529-541
• Main Authors: Peng, Aihong, Zou, Xiuping, He, Yongrui, Chen, Shanchun, Liu, Xiaofeng, Zhang, Jingyun, Zhang, Qingwen, Xie, Zhu, Long, Junhong, Zhao, Xiaochun
• Format: Article
• Language: English
• Subjects: Acids; Biomedical and Life Sciences; Biotechnology; Cell Biology; Citrus fruits; Citrus paradisi; Citrus paradisi - genetics; Citrus paradisi - microbiology; Cyclopentanes - metabolism; Disease Resistance - genetics; Fruits; Gene expression; Gene Expression Regulation, Plant; Genes; Grapefruit; Inoculation; Jasmonic acid; Liberibacter - pathogenicity; Life Sciences; Original Article; Oxylipins - metabolism; Pathogenesis; Pathogens; Phloem - anatomy & histology; Phloem - genetics; Phylogeny; Plant bacterial diseases; Plant Biochemistry; Plant Diseases - microbiology; Plant Proteins - genetics; Plant Sciences; Plants, Genetically Modified - microbiology; Population studies; Reproducibility of Results; Salicylic acid; Salicylic Acid - metabolism; Sequence Analysis, RNA; Starch; Starch - genetics; Starch - metabolism; Transcription; Transcriptomes; Transgenic plants
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-020-02648-3

Key message Overexpression of CiNPR4 enhanced resistance of transgenic citrus plants to Huanglongbing by perceiving the salicylic acid and jasmonic acid signals and up-regulating the transcriptional activities of plant–pathogen interaction genes. Developing transgenic citrus plants with enhanced immunity is an efficient strategy to control citrus Huanglongbing (HLB). Here, a nonexpressor of pathogenesis-related gene 1 ( NPR1 ) like gene from HLB-tolerant ‘Jackson’ grapefruit ( Citrus paradisi Macf.), CiNPR4 , was introduced into ‘Wanjincheng’ orange ( Citrus sinensis Obseck). CiNPR4 expression was determined in transgenic citrus plants using quantitative real-time PCR analyses. The Candidatus Liberibacter asiaticus ( C Las) pathogen of HLB was successfully transmitted to transgenic citrus plants by grafting infected buds. HLB symptoms developed in transgenic and wild-type (WT) plants by 9 months after inoculation. A C Las population analysis showed that 26.9% of transgenic lines exhibited significantly lower C Las titer levels compared with the C Las-infected WT plants at 21 months after inoculation. Lower starch contents and anatomical aberration levels in the phloem were observed in transgenic lines having enhanced resistance compared with C Las-infected WT plants. CiNPR4 overexpression changed the jasmonic acid, but not salicylic acid, level. Additionally, the jasmonic acid and salicylic acid levels increased after C Las infection. Transcriptome analyses revealed that the enhanced resistance of transgenic plants to HLB resulted from the up-regulated transcriptional activities of plant–pathogen interaction-related genes.