Summary Arabidopsis Col‐0 RPP2A and RPP2B confer recognition of Arabidopsis downy mildew (Hyaloperonospora arabidopsidis [Hpa]) isolate Cala2, but the identity of the recognized ATR2Cala2 effector was unknown. To reveal ATR2Cala2, an F2 population was generated from a cross between Hpa‐Cala2 and Hpa‐Noks1. We identified ATR2Cala2 as a non‐canonical RxLR‐type effector that carries a signal peptide, a dEER motif, and WY domains but no RxLR motif. Recognition of ATR2Cala2 and its effector function were verified by biolistic bombardment, ectopic expression and Hpa infection. ATR2Cala2 is recognized in accession Col‐0 but not in Ler‐0 in which RPP2A and RPP2B are absent. In ATR2Emoy2 and ATR2Noks1 alleles, a frameshift results in an early stop codon. RPP2A and RPP2B are essential for the recognition of ATR2Cala2. Stable and transient expression of ATR2Cala2 under 35S promoter in Arabidopsis and Nicotiana benthamiana enhances disease susceptibility. Two additional Col‐0 TIR‐NLR (TNL) genes (RPP2C and RPP2D) adjacent to RPP2A and RPP2B are quantitatively required for full resistance to Hpa‐Cala2. We compared RPP2 haplotypes in multiple Arabidopsis accessions and showed that all four genes are present in all ATR2Cala2‐recognizing accessions.

中文翻译：

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来自拟南芥感染霜霉病的 ATR2Cala2 需要 4 个 TIR-NLR 免疫受体才能完全识别

概括 拟南芥Col-0 RPP2A 和 RPP2B 赋予对拟南芥霜霉病（拟南芥霜霉[帕]) 分离Cala2，但识别ATR2的身份卡拉2效应器未知。 揭示ATR2卡拉2, 一个 F2人口是由两者之间的杂交产生的帕‐Cala2 和帕‐Noks1。我们确定了 ATR2卡拉2作为非典型 RxLR 型效应子，携带信号肽、dEER 基序和 WY 结构域，但没有 RxLR 基序。认可ATR2卡拉2其效应子功能通过基因枪轰击、异位表达和帕感染。 ATR2卡拉2在登录 Col-0 中被识别，但在 Ler-0 中未被识别，其中 RPP2A 和 RPP2B 不存在。在ATR2埃莫伊2和ATR2诺克斯1等位基因，移码导致早期终止密码子。 RPP2A 和 RPP2B 对于识别 ATR2 至关重要卡拉2。稳定和瞬时表达ATR2卡拉235S启动子下拟南芥和本塞姆氏烟草增强疾病的易感性。 另外两个 Col-0 TIR-NLR (TNL) 基因（RPP2C和RPP2D) 毗邻RPP2A和RPP2B完全抵抗所需的数量帕‐卡拉2。我们比较了RP2多个单倍型拟南芥种质并表明所有四个基因都存在于所有 ATR2 中卡拉2‐识别加入物。