Rust (fungus)

Rusts
Example of wheat leaf from a disease differential of Puccinia recondita f.sp. tritici
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Basidiomycota
Class: Pucciniomycetes
Order: Pucciniales
Families

Rusts are fungal plant pathogens of the order Pucciniales (previously known as Uredinales) causing plant fungal diseases.

An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus Puccinia, are currently accepted.[3] Rust fungi are highly specialized plant pathogens with several unique features. Taken as a group, rust fungi are diverse and affect many kinds of plants. However, each species has a range of hosts and cannot be transmitted to non-host plants. In addition, most rust fungi cannot be grown easily in pure culture.

Most species of rust fungi are able to infect two different plant hosts in different stages of its life cycle, and may produce up to five morphologically and cytologically distinct spore-producing structures viz., spermogonia, aecia, uredinia, telia, and basidia in successive stages of reproduction.[4] Each spore type is very host specific, and can typically infect only one kind of plant.

Rust fungi are obligate plant pathogens that only infect living plants. Infections begin when a spore lands on the plant surface, germinates, and invades its host. Infection is limited to plant parts such as leaves, petioles, tender shoots, stem, fruits, etc.[3] Plants with severe rust infection may appear stunted, chlorotic (yellowed), or may display signs of infection such as rust fruiting bodies. Rust fungi grow intracellularly, and make spore-producing fruiting bodies within or, more often, on the surfaces of affected plant parts.[3] Some rust species form perennial systemic infections that may cause plant deformities such as growth retardation, witch's broom, stem canker, galls, or hypertrophy of affected plant parts.

Rusts get their name because they are most commonly observed as deposits of powdery rust-coloured or brown spores on plant surfaces. The Roman agricultural festival Robigalia (April 25) has ancient origins in combating wheat rust.[5]

  1. ^ a b c d e f g Aime, M. C.; McTaggart, A. R. (2021). "A higher-rank classification for rust fungi, with notes on genera". Fungal Systematics and Evolution. 7: 21–47. doi:10.3114/fuse.2021.07.02. PMC 8165960. PMID 34124616.
  2. ^ "Species Fungorum - Search Page". www.speciesfungorum.org. Archived from the original on 9 October 2023. Retrieved 27 October 2022.
  3. ^ a b c Mohanan, C. (2010). Rust Fungi of Kerala. Kerala, India: Kerala Forest Research Institute. p. 148. ISBN 978-81-85041-72-8.
  4. ^ Kolmer, James A; Ordonez, Maria E; Groth, James V (2001). eLS. John Wiley & Sons, Ltd. doi:10.1002/9780470015902.a0021264. ISBN 9780470015902. S2CID 1434349.
  5. ^ Evans, R. (2007). Utopia Antiqua: Readings of the Golden Age and Decline at Rome. Taylor & Francis. ISBN 978-1-134-48787-5. Archived from the original on 2023-10-09. Retrieved 2018-01-12.