Email updates

Keep up to date with the latest news and content from BMC Plant Biology and BioMed Central.

Open Access Highly Accessed Research article

Characterization of non-host resistance in broad bean to the wheat stripe rust pathogen

Yulin Cheng1, Hongchang Zhang12, Juanni Yao1, Xiaojie Wang1, Jinrong Xu13, Qingmei Han1, Guorong Wei1, Lili Huang1 and Zhensheng Kang1*

Author Affiliations

1 State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China

2 College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, People’s Republic of China

3 Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA

For all author emails, please log on.

BMC Plant Biology 2012, 12:96  doi:10.1186/1471-2229-12-96

Published: 21 June 2012

Abstract

Background

Non-host resistance (NHR) confers plant species immunity against the majority of microbial pathogens and represents the most robust and durable form of plant resistance in nature. As one of the main genera of rust fungi with economic and biological importance, Puccinia infects almost all cereals but is unable to cause diseases on legumes. Little is known about the mechanism of this kind of effective defense in legumes to these non-host pathogens.

Results

In this study, the basis of NHR in broad bean (Vicia faba L.) against the wheat stripe rust pathogen, Puccinia striiformis f. sp. tritici (Pst), was characterized. No visible symptoms were observed on broad bean leaves inoculated with Pst. Microscopic observations showed that successful location of stomata and haustoria formation were significantly reduced in Pst infection of broad bean. Attempted infection induced the formation of papillae, cell wall thickening, production of reactive oxygen species, callose deposition and accumulation of phenolic compounds in plant cell walls. The few Pst haustoria that did form in broad bean cells were encased in reactive oxygen and callose materials and those cells elicited cell death. Furthermore, a total of seven defense-related genes were identified and found to be up-regulated during the Pst infection.

Conclusions

The results indicate that NHR in broad bean against Pst results from a continuum of layered defenses, including basic incompatibility, structural and chemical strengthening of cell wall, posthaustorial hypersensitive response and induction of several defense-related genes, demonstrating the multi-layered feature of NHR. This work also provides useful information for further determination of resistance mechanisms in broad bean to rust fungi, especially the adapted important broad bean rust pathogen, Uromyces viciae-fabae, because of strong similarity and association between NHR of plants to unadapted pathogens and basal resistance of plants to adapted pathogens.

Keywords:
Broad bean; Cell wall; Expression profile; Haustorium; Non-host resistance; Rust fungus