An ANNEXIN-like protein from the cereal cyst nematode Heterodera avenae suppresses plant defense

• Published in: PloS one Vol. 10; no. 4; p. e0122256
• Main Authors: Chen, Changlong, Liu, Shusen, Liu, Qian, Niu, Junhai, Liu, Pei, Zhao, Jianlong, Jian, Heng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.04.2015; Public Library of Science (PLoS)
• Subjects: Amino Acid Sequence; Amino acids; Animals; Annexins - chemistry; Annexins - genetics; Annexins - metabolism; Apoptosis; Arabidopsis; Barley; Bax protein; Cell death; Cloning, Molecular; Females; Gene expression; Gene Silencing; Genes; Genetic engineering; Genomes; Genomics; Health aspects; Heterodera avenae; Heterodera schachtii; Homology; Host-Parasite Interactions; Hybridization; Identification; Immunity; Infections; Kinases; Localization; MAP kinase; MAP Kinase Kinase 1 - metabolism; MAP Kinase Kinase Kinases - metabolism; Metabolism; Microscopy, Fluorescence; Mitogens; Molecular Sequence Data; Mosaic Viruses - genetics; Nematodes; Nicotiana - metabolism; Parasitism; Pathogens; Physiology; Plant pathology; Plant Proteins - metabolism; Plant sciences; Plant virus diseases; Polymerase chain reaction; Protein kinase; Proteins; Proteomics; Roundworms; Sequence Alignment; Signal Transduction; Southern blotting; Stress response; Trends; Triticum; Tylenchoidea - physiology; Up-Regulation; Viruses; Wheat; Beijing China; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0122256

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.