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ABSTRACT Understanding how pathogens infect different tissue types and how plants mount tissue‐specific defences against bacterial pathogens is critical for improving disease resistance.Xanthomonas vasicolapv.vasculorum(Xvv) is a bacterial pathogen of maize that exhibits both vascular and nonvascular lifestyles, offering a unique opportunity to dissect host–pathogen interactions across tissue types. Here, we combined fluorescence microscopy, dual RNA‐seq and functional genetics to characterize the interactions between Xvv and maize, both vascular and nonvascular. Using distinct inoculation methods, we reveal temporally and spatially divergent colonization patterns and transcriptional responses in resistant (B73) and susceptible (CML333) maize lines. We show, using transposon insertion lines, that a malectin‐like receptor kinase (ZmCrRLK1L19) confers resistance to vascular disease. The gene colocalizes with a major Xvv vascular resistance QTL. Xvv modulates motility and virulence gene expression depending on tissue context; flagellar motility is essential for mesophyll colonization but is dispensable in the xylem. These findings reveal mechanisms underlying tissue‐specific resistance and pathogen tissue tropism, providing a foundation for improving broad‐spectrum disease resistance in cereal crops.
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This content will become publicly available on February 1, 2027
Vascular Pathogenicity of Xanthomonas vasicola pv. vasculorum in Maize Is Modulated by Tissue-Specific Host Resistance
How host genotype shapes pathogen tissue tropism remains poorly understood. Vascular and nonvascular tissues represent distinct habitats within a plant for bacteria to colonize. Host plants often utilize different mechanisms to defend themselves against vascular and nonvascular pathogens, and mechanisms of resistance employed by the host can vary by organ. Xanthomonas vasicola pv. vasculorum ( Xvv) is an emerging bacterial maize pathogen, and this pathosystem offers an opportunity to study how host resistance differs in response to the vascular and nonvascular lifestyles exhibited by a single bacterial phytopathogen. We used different inoculation techniques to induce vascular and nonvascular disease and evaluated maize populations using both techniques to map resistance to vascular and nonvascular disease caused by Xvv. Xvv can colonize both vascular and nonvascular tissues, depending on the genotype. Different inoculation techniques can be used to induce vascular or nonvascular colonization. Independent loci control variation in resistance to Xvv during vascular and nonvascular pathogenesis. We confirmed the role of those regions in resistance to vascular and nonvascular infection. This study offers insights into how host resistance shapes how bacterial pathogens adapt to both vascular and nonvascular lifestyles. We show that host genotype can dictate which tissues a pathogen can infect. This system can serve as a model to understand tissue-specific host resistance to plant pathogens and tissue specificity in pathogens.
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- Award ID(s):
- 2154872
- PAR ID:
- 10690695
- Publisher / Repository:
- The American Phytopathological Society
- Date Published:
- Journal Name:
- Phytopathology®
- Volume:
- 116
- Issue:
- 2
- ISSN:
- 0031-949X
- Page Range / eLocation ID:
- 285 to 297
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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