title: An ANNEXIN-like protein from the cereal cyst nematode Heterodera avenae suppresses plant defense.
abstract: Parasitism genes encoding secreted effector proteins of plant-parasitic nematodes play important roles in facilitating parasitism. An annexin-like gene was isolated from the cereal cyst nematode Heterodera avenae (termed Ha-annexin) and had high similarity to annexin 2, which encodes a secreted protein of Globodera pallida. Ha-annexin encodes a predicted 326 amino acid protein containing four conserved annexin domains. Southern blotting revealed that there are at least two homologies in the H. avenae genome. Ha-annexin transcripts were expressed within the subventral gland cells of the pre-parasitic second-stage juveniles by in situ hybridization. Additionally, expression of these transcripts were relatively higher in the parasitic second-stage juveniles by quantitative real-time RT-PCR analysis, coinciding with the time when feeding cell formation is initiated. Knockdown of Ha-annexin by method of barley stripe mosaic virus-based host-induced gene silencing (BSMV-HIGS) caused impaired nematode infections at 7 dpi and reduced females at 40 dpi, indicating important roles of the gene in parasitism at least in early stage in vivo. Transiently expression of Ha-ANNEXIN in onion epidermal cells and Nicotiana benthamiana leaf cells showed the whole cell-localization. Using transient expression assays in N. benthamiana, we found that Ha-ANNEXIN could suppress programmed cell death triggered by the pro-apoptotic mouse protein BAX and the induction of marker genes of PAMP-triggered immunity (PTI) in N. benthamiana. In addition, Ha-ANNEXIN targeted a point in the mitogen-activated protein kinase (MAPK) signaling pathway downstream of two kinases MKK1 and NPK1 in N. benthamiana.
authors: Department of Plant Pathology, China Agricultural University, Beijing, China.
authors: Changlong
authors: C
authors: Chen
authors: Department of Plant Pathology, China Agricultural University, Beijing, China; Institute of Plant Protection and Agro-products Safety, Anhui Academy of Agricultural Sciences, Hefei, Anhui, China.
authors: Shusen
authors: S
authors: Liu
authors: Department of Plant Pathology, China Agricultural University, Beijing, China.
authors: Qian
authors: Q
authors: Liu
authors: Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, Hainan, China.
authors: Junhai
authors: J
authors: Niu
authors: Department of Plant Pathology, China Agricultural University, Beijing, China.
authors: Pei
authors: P
authors: Liu
authors: Department of Plant Pathology, China Agricultural University, Beijing, China.
authors: Jianlong
authors: J
authors: Zhao
authors: Department of Plant Pathology, China Agricultural University, Beijing, China.
authors: Heng
authors: H
authors: Jian
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017302:Annexins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D003001:Cloning, Molecular; D020868:Gene Silencing; D006790:Host-Parasite Interactions; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction; D014026:Nicotiana / Q000378:metabolism*; D014431:Tylenchoidea / Q000502:physiology*; D015854:Up-Regulation
chemical_list: D017302:Annexins; D010940:Plant Proteins; D020930:MAP Kinase Kinase Kinases; C082276:NPK1 protein, Nicotiana tabacum; D048369:MAP Kinase Kinase 1