Wheat yellow rust (''Puccinia striiformis''

f.sp. ''Forma specialis'' (plural: ''formae speciales''), abbreviated f. sp. (plural ff. spp.) without italics, is an informal taxonomic grouping allowed by the International Code of Nomenclature for algae, fungi, and plants, that is applied to a paras ...

''tritici''), also known as wheat stripe rust, is one of the three major

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeolog ...

rust Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH), ...

diseases, along with stem rust of wheat (''Puccinia graminis'' f.sp. tritici) and leaf rust (''Puccinia triticina'' f.sp. tritici).

History

As R.P. Singh, J. Huerta-Espino, and A.P. Roelfs say in their 2002 comprehensive review of literature on the wheat rusts for UN

FAO The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

Although Gadd first described stripe rust of wheat in 1777, it was not until 1896 that Eriksson and Henning (1896) showed that stripe rust resulted from a separate pathogen, which they named ''P. glumarum''. In 1953, Hylander et al. (1953) revived the name ''P. striiformis''.

A stripe rust outbreak in northwest Syria contributed to the beginning of the Syrian Civil War by increasing food prices.

Life cycle

Other cereal rust fungi have macrocyclic,

heteroecious A heteroecious parasite is one that requires at least two hosts. The ''primary host'' is the host in which the parasite spends its adult life; the other is the ''secondary host''. Both hosts are required for the parasite to complete its life cycl ...

life cycles, involving five spore stages and two

phylogenetically In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

unrelated hosts. ''P. striiformis'' was thought to be microcyclic for centuries until 2009, when a team of scientists at the USDA-ARS

Cereal Disease Lab A cereal is any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food ...

led by Yue Jin confirmed that barberry (''

Berberis ''Berberis'' (), commonly known as barberry, is a large genus of deciduous and evergreen shrubs from tall, found throughout temperate and subtropical regions of the world (apart from Australia). Species diversity is greatest in South America an ...

'' and ''

Mahonia ''Mahonia'' is a genus of approximately 70 species of evergreen shrubs and, rarely, small trees in the family Berberidaceae, native to eastern Asia, the Himalaya, North and Central America. They are closely related to the genus '' Berberis'' a ...

'' spp.) is an alternate host. Barberry was known as an alternate host of the closely related stem rust (''

Puccinia graminis Stem rust, also known as cereal rust, black rust, red rust or red dust, is caused by the fungus ''Puccinia graminis'', which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat, durum wh ...

'') and for many years, when infection was observed on barberry, it was assumed to be stem rust. (Then ''P. striiformis'' was accidentally discovered to ''also'' have the same alternate host when scientists observed rust infection on various

barberry ''Berberis'' (), commonly known as barberry, is a large genus of deciduous and evergreen shrubs from tall, found throughout temperate and subtropical regions of the world (apart from Australia). Species diversity is greatest in South America ...

species, and inoculated spores of this unknown rust onto Poaceae hosts.

Kentucky Bluegrass ''Poa pratensis'', commonly known as Kentucky bluegrass (or blue grass), smooth meadow-grass, or common meadow-grass, is a perennial species of grass native to practically all of Europe, North Asia and the mountains of Algeria and Morocco. Altho ...

was the only one to show infection. The

uredinia {{Short pages monitor