Targeted promoter editing for rice resistance to Xanthomonas oryzae pv. oryzae reveals differential activities for SWEET14-inducing TAL effectors.
Targeted promoter editing for rice resistance to Xanthomonas oryzae pv. oryzae reveals differential activities for SWEET14-inducing TAL effectors.
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DOI：
10.1111/pbi.12613
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发表时间：
2017-03
影响因子：
13.8
通讯作者：
Koebnik R
中科院分区：
文献类型：
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作者：
Blanvillain-Baufumé S;Reschke M;Solé M;Auguy F;Doucoure H;Szurek B;Meynard D;Portefaix M;Cunnac S;Guiderdoni E;Boch J;Koebnik R
黄单胞菌白叶枯病菌（Xanthomonasleafpv.）Xoo将称为转录激活因子样效应子（TALE）的DNA结合蛋白注入植物细胞，该蛋白以序列特异性方式结合效应子结合元件（EBE），导致宿主基因诱导。TALE AvrXa7、PthXo3、TalC和Tal5均以OsSWEET14为靶标，是水稻与Xoo互作的主要易感因子。在这里，我们报告了通过在水稻中稳定表达TALE核酸酶（TALEN）构建体来产生OsSWEET 14启动子的等位基因文库。评估了携带AvrXa7、Tal 5或TalC EBE突变的细胞系的敏感性水平。在AvrXa7或Tal5 EBE中编辑的植物对依赖于相应TALE的细菌菌株具有抗性。令人惊讶的是，虽然TalC EBE内的插入缺失阻止了OsSWEET 14响应于依赖TalC的BAI3野生型细菌的诱导，但TalC响应性的丧失未能赋予对该菌株的抗性。然而，TalC EBE突变株系对表达人工SWEET 14诱导TALE的菌株具有抗性，该菌株的EBE也在该株系中被编辑。这项工作提供了在TalC EBE中编辑的第一组等位基因，并揭示了与AvrXa7或Tal5相比TalC的独特的、更广泛的活性范围。我们提出除了SWEET 14之外，TalC还存在其他靶标，这表明TALE介导的植物易感性可能是由单个效应子诱导几个遗传冗余的宿主易感性基因引起的。
As a key virulence strategy to cause bacterial leaf blight, Xanthomonas oryzae pv. oryzae (Xoo) injects into the plant cell DNA‐binding proteins called transcription activator‐like effectors (TALEs) that bind to effector‐binding elements (EBEs) in a sequence‐specific manner, resulting in host gene induction. TALEs AvrXa7, PthXo3, TalC and Tal5, found in geographically distant Xoo strains, all target OsSWEET14, thus considered as a pivotal TALE target acting as major susceptibility factor during rice–Xoo interactions. Here, we report the generation of an allele library of the OsSWEET14 promoter through stable expression of TALE‐nuclease (TALEN) constructs in rice. The susceptibility level of lines carrying mutations in AvrXa7, Tal5 or TalC EBEs was assessed. Plants edited in AvrXa7 or Tal5 EBEs were resistant to bacterial strains relying on the corresponding TALE. Surprisingly, although indels within TalC EBE prevented OsSWEET14 induction in response to BAI3 wild‐type bacteria relying on TalC, loss of TalC responsiveness failed to confer resistance to this strain. The TalC EBE mutant line was, however, resistant to a strain expressing an artificial SWEET14‐inducing TALE whose EBE was also edited in this line. This work offers the first set of alleles edited in TalC EBE and uncovers a distinct, broader range of activities for TalC compared to AvrXa7 or Tal5. We propose the existence of additional targets for TalC beyond SWEET14, suggesting that TALE‐mediated plant susceptibility may result from induction of several, genetically redundant, host susceptibility genes by a single effector.