Engineering a Decoy Substrate in Soybean to Enable Recognition of the Soybean Mosaic Virus NIa Protease
Engineering a Decoy Substrate in Soybean to Enable Recognition of the Soybean Mosaic Virus NIa Protease
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DOI：
10.1094/mpmi-12-18-0324-r
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发表时间：
2019-06-01
影响因子：
3.5
通讯作者：
Innes, Roger W.
中科院分区：
文献类型：
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作者：
Helm, Matthew;Qi, Mingsheng;Innes, Roger W.
在拟南芥中，来自假单胞菌的AvrPphB效应蛋白酶的识别是由抗病（R）蛋白RPS 5介导的，其通过AvrPphB诱导的拟南芥蛋白激酶PBS 1的切割而被激活。RPS 5的识别特异性可以通过用其他蛋白酶（包括来自病毒的蛋白酶）的切割序列取代PBS 1内的AvrPphB切割位点来改变。AvrPphB还激活大豆（Glycine max）中的防御反应，表明大豆可能含有类似于RPS 5的R蛋白。然而，尚不清楚这种反应是否由大豆PBS 1样蛋白的切割介导。在这里，我们表明，大豆含有三个PBS 1直系同源物，其产品被AvrPphB切割。此外，在其AvrPphB切割位点含有5-丙氨酸插入的大豆PBS 1衍生物的瞬时表达激活了大豆原生质体中的细胞死亡，表明大豆可能含有由大豆PBS 1蛋白的构象变化激活的AvrPphB特异性抗性蛋白。值得注意的是，我们表明，大豆PBS 1诱饵蛋白修饰含有一个切割位点的大豆花叶病毒（SMV）NIa蛋白酶触发细胞死亡，在大豆原生质体时，这种蛋白酶切割，表明PBS 1诱饵的方法将在大豆中工作，使用内源性PBS 1基因。最后，我们表明，激活的AvrPphB依赖的细胞死亡反应有效地抑制大豆SMV的系统传播。这些数据还表明，诱饵工程可能是可行的，在其他作物植物物种，识别AvrPphB蛋白酶活性。
In Arabidopsis, recognition of the AvrPphB effector protease from Pseudomonas syringae is mediated by the disease resistance (R) protein RPS5, which is activated by AvrPphB-induced cleavage of the Arabidopsis protein kinase PBS1. The recognition specificity of RPS5 can be altered by substituting the AvrPphB cleavage site within PBS1 with cleavage sequences for other proteases, including proteases from viruses. AvrPphB also activates defense responses in soybean (Glycine max), suggesting that soybean may contain an R protein analogous to RPS5. It was unknown, however, whether this response is mediated by cleavage of a soybean PBS1-like protein. Here, we show that soybean contains three PBS1 orthologs and that their products are cleaved by AvrPphB. Further, transient expression of soybean PBS1 derivatives containing a five-alanine insertion at their AvrPphB cleavage sites activated cell death in soybean protoplasts, demonstrating that soybean likely contains an AvrPphB-specific resistance protein that is activated by a conformational change in soybean PBS1 proteins. Significantly, we show that a soybean PBS1 decoy protein modified to contain a cleavage site for the soybean mosaic virus (SMV) NIa protease triggers cell death in soybean protoplasts when cleaved by this protease, indicating that the PBS1 decoy approach will work in soybean, using endogenous PBS1 genes. Lastly, we show that activation of the AvrPphB-dependent cell death response effectively inhibits systemic spread of SMV in soybean. These data also indicate that decoy engineering may be feasible in other crop plant species that recognize AvrPphB protease activity.