Rosette core fungal resistance in Arabidopsis thaliana

• Published in: Planta 2019-12, Vol.250 (6), p.1941-1953
• Main Authors: Dai, Yanwan, Ogilvie, Huw A., Liu, Yuan, Huang, Michael, Markillie, Lye Meng, Mitchell, Hugh D., Borrego, Eli J., Kolomiets, Michael V., Gaffrey, Matthew J., Orr, Galya, Chehab, E. Wassim, Mao, Wan-Ting, Braam, Janet
• Format: Article
• Language: English
• Subjects: Abscission; Age; Agriculture; Arabidopsis - immunology; Arabidopsis - microbiology; Arabidopsis - physiology; Arabidopsis thaliana; BASIC BIOLOGICAL SCIENCES; Biomedical and Life Sciences; Biotic stress; Botrytis; Botrytis cinerea; Brassicaceae; Cauliflowers; Disease Resistance; Ecology; Forestry; Fungi; Gene expression; Gene Expression Profiling; Host plants; Inoculation; Jasmonate; Jasmonic acid; Leaves; Life Sciences; Organs; ORIGINAL ARTICLE; Plant defense; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Growth Regulators - metabolism; Plant Leaves - immunology; Plant Leaves - microbiology; Plant Sciences; Plants; Real-Time Polymerase Chain Reaction; RNA-seq; Rosette
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-019-03273-5

Arabidopsis thaliana is a model host to investigate plant defense against fungi. However, many of the reports investigating Arabidopsis fungal defense against the necrotrophic fungus, Botrytis cinerea, utilize rosette leaves as host tissue. Here we report organ-dependent differences in B. cinerea resistance of Arabidopsis. Although wild-type Arabidopsis rosette leaves mount a jasmonate-dependent defense that slows fungal growth, this defense is incapable of resisting fungal devastation. In contrast, as the fungus spreads through infected leaf petioles towards the plant center, or rosette core, there is a jasmonate- and age-dependent fungal penetration blockage into the rosette core. We report evidence for induced and preformed resistance in the rosette core, as direct rosette core inoculation can also result in resistance, but at a lower penetrance relative to infections that approach the core from infected leaf petioles. The Arabidopsis rosette core displays a distinct transcriptome relative to other plant organs, and BLADE ON PETIOLE (BOP) transcripts are abundant in the rosette core. The BOP genes, with known roles in abscission zone formation, are required for full Arabidopsis rosette core B. cinerea resistance, suggesting a possible role for BOP-dependent modifications that may help to restrict fungal susceptibility of the rosette core. Finally, we demonstrate that cabbage and cauliflower, common Brassicaceae crops, also display leaf susceptibility and rosette core resistance to B. cinerea that can involve leaf abscission. Thus, spatial and developmental aspects of plant host resistance play critical roles in resistance to necrotrophic fungal pathogens and are important to our understanding of plant defense mechanisms.