Open Access

ARTICLE

Early Spatiotemporal Dynamic of Green Fluorescent Protein-Tagged Fusarium oxysporum f. sp. batatas in Susceptible and Resistant Sweet Potato

Hong Zhang^1,2,#, Ying Zhu^3,#, Xingyu Li^3,#, Zhonghua Liu^1,2, Guoliang Li^1,2, Zhaomiao Lin^1,2, Yongxiang Qiu^1,2, Yongqing Xu^1,2, Shimin Lyu³, Jiyang Wang³, Sixin Qiu^1,2,*

1 Institute of Crop Sciences, Fujian Academy of Agricultural Sciences, Fuzhou, 350013, China
2 Scientific Observing and Experimental Station of Tuber and Root Crops in South China, Ministry of Agriculture and Rural Affairs, Fuzhou, 350013, China
3 Department of Plant Pathology, The Ministry of Agriculture Key Laboratory of Pest Monitoring and Green Management and Joint International Research Laboratory of Crop Molecular Breeding, Ministry of Education, China Agricultural University, Beijing, 100193, China

* Corresponding Author: Sixin Qiu. Email:
# These authors contributed equally to this article

Phyton-International Journal of Experimental Botany 2025, 94(8), 2479-2498. https://doi.org/10.32604/phyton.2025.064850

Received 25 February 2025; Accepted 05 August 2025; Issue published 29 August 2025

Abstract

Vascular wilt caused by Fusarium oxysporum f. sp. batatas (Fob) is a devastating disease threatening global sweet potato production. To elucidate Fob’s pathogenicity mechanisms and inform effective control strategies, we generated a green fluorescent protein (GFP)-tagged Fob strain to track infection dynamics in sweet potato susceptible cultivar Xinzhonghua and resistant cultivar Xiangshu75-55, respectively. Through cytological observation, we found in the susceptible Xinzhonghua, Fob predominantly colonized stem villi, injured root growth points, and directly invaded vascular bundles through stem wounds. Spore germination peaked at 2–3 h post-inoculation (hpi), followed by cyclical mycelial expansion and sporulation within vascular tissues with sustaining infection. In contrast, the resistant Xiangshu75-55 exhibited strong suppression of Fob: spores rarely germinated in vascular bundles or on trichomes by 3 hpi, and mature hyphae were absent in stems at 24 hpi. Quantitative reverse transcription PCR (qRT-PCR) confirmed significantly higher Fob biomass in Xinzhonghua than in Xiangshu75-55 by 16 hpi. Additionally, transcriptional profiling revealed distinct pathogen-host interactions during the compatible and incompatible reactions. In Xinzhonghua, Fob virulence genes FobPGX1, FobICL1, FobCTF2, FobFUB5 and FobFUB6 were upregulated within 16 hpi. Conversely, host defense genes IbMAPKK9, IbWRKY61, IbWRKY75, IbSWEET10, IbBBX24 and IbPIF4 were activated in Xiangshu75-55 during the same period. This study provides spatiotemporal cytological and molecular insights into Fob pathogenicity and host resistance, offering a foundation for early disease detection and improved Fusarium wilt management in sweet potato.

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Supplementary Material

Supplementary Material File

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