Stem rust, also known as cereal rust, black rust, red rust, or red dust, is a disease caused by the fungus Puccinia graminis f. sp. tritici in cereal crops, with susceptible Wheat being the most important host. Stem rust (black rust) is a common disease of barberry and other Berberis, Mahoberberis, and Mahonia species. It decreases grain quality and causes severe yield losses. The fungus affects the plant’s stem and leaves, causing rusty-colored pustules that burst and release spores of spores that spread the illness to neighboring plants.
Stem Rust disease management in Wheat
The causal organism of Stem rust disease
- Rust fungi are obligatory parasites that grow and reproduce on live host tissue.
- The species that causes stem rust, Puccinia graminis, is heteroecious, needing two unrelated host plants to complete its life cycle.
- Puccinia graminis is a macrocyclic organism with five spore phases.
- There is significant genetic variety within the species, with subspecies and races of the fungus known to exist.
- Puccinia graminis f. sp. tritici causes wheat stem rust, while P. graminis f.sp. secalis causes rye stem rust and P. graminis f.sp. avenae causes oat stem rust.
Disease cycle of Stem rust disease
It only survives on living hosts from one season to the next. The greatest carryover occurs during wet summers and autumns. Rust fragments can be spread quickly by wind, and the establishment of stem rust is favored by wet conditions and temperatures of 15-30°C. In comparison to stripe rust, stem rust typically appears later in the season.
Its obligate biotrophic lifestyle necessitates the activation of specific gene transcriptions. It constitutes biotrophy genomic features, which have parallels in other eukaryotic plant pathogens and show a convergent evolution around the plant pathogenic lifestyle.
The life cycle of Puccinia graminis
- Stage 0: Spermogonium stage. During this stage, the fungus produces spermatia and receptive hyphae.
- Stage I: Aecium stage. During this stage, the fungus produces aeciospores.
- Stage II: Uredium stage. During this stage, the fungus produces urediospores.
- Stage III: Telium stage. During this stage, the fungus produces teliospores.
- Stage IV: Basidium stage. During this stage, the fungus produces basidiospores.
Each of these spore stages plays a key role in the life cycle of Puccinia graminis; they contribute to the spread and survival of the fungus in the environment.
Favorable conditions for the spread of Stem rust disease
- Both live on stubbles a