title: TaMCA4, a novel wheat metacaspase gene functions in programmed cell death induced by the fungal pathogen Puccinia striiformis f. sp. tritici.
abstract: Programmed cell death (PCD) is a physiological process to remove redundant or harmful cells, for the development of multicellular organisms, or for restricting the spread of pathogens (hypersensitive response). Metacaspases are cysteine-dependent proteases which play an essential role in PCD. Triticum aestivum metacaspase 4 (TaMCA4) is a type II metacaspase gene cloned from 'Suwon11' wheat, with typical structural features such as peptidase C14 caspase domain and a long linker sequence between the two subunits. Transient expression of TaMCA4 in tobacco leaves failed to induce PCD directly but enhanced cell death triggered by a mouse Bax gene or a candidate effector gene from Puccinia striiformis f. sp. tritici. Enhancement of PCD was also observed in wheat leaves co-bombarded with TaMCA4. When challenged with the avirulent race of P. striiformis f. sp. tritici, the expression level of TaMCA4 in wheat leaves was sharply upregulated, whereas the transcript level was not significantly induced by the virulent race. Moreover, knocking down TaMCA4 expression by virus-induced gene silencing enhanced the susceptibility of Suwon11 to the avirulent race of P. striiformis f. sp. tritici and reduced the necrotic area at infection sites.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wang
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Feng
authors.forename: Chunlei
authors.initials: C
authors.lastname: Tang
authors.forename: Pengfei
authors.initials: P
authors.lastname: Bai
authors.forename: Guorong
authors.initials: G
authors.lastname: Wei
authors.forename: Lili
authors.initials: L
authors.lastname: Huang
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Kang
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000502:physiology*; D001487:Basidiomycota / Q000502:physiology*; D020169:Caspases / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D020868:Gene Silencing; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism; D014158:Transcription, Genetic; D014908:Triticum / Q000201:enzymology* / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D020169:Caspases