Emergence and spread of new races of wheat stem rust: continued threat to food security and prospects of genetic control

Authors: SINGH, RAVI - International Maize & Wheat Improvement Center (CIMMYT); HODSON, DAVID - International Maize & Wheat Improvement Center (CIMMYT); Jin, Yue; LAGUDAH, EVANS - Commonwealth Scientific And Industrial Research Organisation (CSIRO); AYLIFFE, MICHAEL - Commonwealth Scientific And Industrial Research Organisation (CSIRO); BHAVANI, SRIDHAR - International Maize & Wheat Improvement Center (CIMMYT); Rouse, Matthew; PRETORIUS, ZACHARIAS - University Of The Free State; Szabo, Les; HUERTA-ESPINO, JULIO - Instituto Nacional De Investigaciones Forestales Y Agropecuarias (INIFAP); BASNET, BHOJA - International Maize & Wheat Improvement Center (CIMMYT); LAN, CAIXIA - International Maize & Wheat Improvement Center (CIMMYT); HOVMOLLER, MOGENS - Aarhus University

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 6/29/2015
Publication Date: 7/29/2015
Citation: Singh, R.P., Hodson, D.P., Jin, Y., Lagudah, E.S., Ayliffe, M.A., Bhavani, S., Rouse, M.N., Pretorius, Z.A., Szabo, L.J., Huerta-Espino, J., Basnet, B.R., Lan, C., Hovmoller, M.S. 2015. Emergence and spread of new races of wheat stem rust: continued threat to food security and prospects of genetic control. Book Chapter. 105(7):872-884. https://doi.org/10.1094/PHYTO-01-15-0030-FI.
DOI: https://doi.org/10.1094/PHYTO-01-15-0030-FI

Interpretive Summary: Cereals are gramineous plants cultivated for stable human food and animal feed. The cereal crop species are attacked by a number of rust fungi, known as cereal rusts. These rust pathogens are heteroecious, completing their life history on two unrelated hosts, a cereal host and an alternate host, with multiple spore stages. During a crop season, multiple generations of urediniospores are produced when environmental conditions are conducive and receptive hosts are available, resulting in large volumes of spores that incite local epidemics, or disperse into new areas. Cereal rusts remain to be some of the most challenging plant diseases for crop management, and continue to pose a threat to stable cereal production worldwide. The difficulties in achieving a satisfactory control is largely due to constant evolving rust pathogens with regular occurrence of virulent forms or races that renders deployed resistance ineffective, and the airborne dispersal of spores that results in potential aerial incursions of new races from neighboring wheat producing regions. Most of the cereal rusts also have unique ability to rapidly multiply when conditions are conducive, causing explosive epidemics. The spatial, temporal and genetic uniformity in cereal crops and their productions combined with virulent and aggressive pathogen races have facilitated epidemics of regional, and sometimes continental, in scales. The chapter describes the biology, epidemiology, host-pathogen interactions, and genetic control of the three rust diseases on wheat: stem rust caused by Puccinia graminis f. sp. tritici, leaf rust caused by P. triticina, and stripe rust caused by P. striiformis f. sp. tritici.

Technical Abstract: Cereals are gramineous plants cultivated for stable human food and animal feed. The cereal crop species are attacked by a number of rust fungi, known as cereal rusts. These rust pathogens are heteroecious, completing their life history on two unrelated hosts, a cereal host and an alternate host, with multiple spore stages. During a crop season, multiple generations of urediniospores are produced when environmental conditions are conducive and receptive hosts are available, resulting in large volumes of spores that incite local epidemics, or disperse into new areas. Cereal rusts remain to be some of the most challenging plant diseases for crop management, and continue to pose a threat to stable cereal production worldwide. The difficulties in achieving a satisfactory control is largely due to constant evolving rust pathogens with regular occurrence of virulent forms or races that renders deployed resistance ineffective, and the airborne dispersal of spores that results in potential aerial incursions of new races from neighboring wheat producing regions. Most of the cereal rusts also have unique ability to rapidly multiply when conditions are conducive, causing explosive epidemics. The spatial, temporal and genetic uniformity in cereal crops and their productions combined with virulent and aggressive pathogen races have facilitated epidemics of regional, and sometimes continental, in scales. The chapter describes the biology, epidemiology, host-pathogen interactions, and genetic control of the three rust diseases on wheat: stem rust caused by Puccinia graminis f. sp. tritici, leaf rust caused by P. triticina, and stripe rust caused by P. striiformis f. sp. tritici.