Australian Research Council Centre of Excellence in Plant Energy Biology, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia.
School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia.
New Phytol. 2017 Jul;215(1):77-84. doi: 10.1111/nph.14599. Epub 2017 May 17.
Plants sense microbial signatures via activation of pattern recognition receptors (PPRs), which trigger a range of cellular defences. One response is the closure of plasmodesmata, which reduces symplastic connectivity and the capacity for direct molecular exchange between host cells. Plasmodesmal flux is regulated by a variety of environmental cues but the downstream signalling pathways are poorly defined, especially the way in which calcium regulates plasmodesmal closure. Here, we identify that closure of plasmodesmata in response to bacterial flagellin, but not fungal chitin, is mediated by a plasmodesmal-localized Ca -binding protein Calmodulin-like 41 (CML41). CML41 is transcriptionally upregulated by flg22 and facilitates rapid callose deposition at plasmodesmata following flg22 treatment. CML41 acts independently of other defence responses triggered by flg22 perception and reduces bacterial infection. We propose that CML41 enables Ca -signalling specificity during bacterial pathogen attack and is required for a complete defence response against Pseudomonas syringae.
植物通过激活模式识别受体（PPRs）来感知微生物特征，从而触发一系列细胞防御反应。其中一种反应是胞间连丝的关闭，这会降低质体的连接性和宿主细胞之间直接分子交换的能力。胞间连丝的流动受到各种环境线索的调节，但下游信号通路的定义很差，特别是钙如何调节胞间连丝的关闭。在这里，我们发现，细菌鞭毛蛋白而非真菌几丁质诱导的胞间连丝关闭是由质膜定位的钙结合蛋白钙调素样 41（CML41）介导的。CML41 转录水平受 flg22 上调，并在 flg22 处理后促进快速在胞间连丝沉积胼胝质。CML41 独立于 flg22 感知触发的其他防御反应，减少了细菌感染。我们提出，CML41 在细菌病原体攻击期间实现了钙信号的特异性，并对拟南芥抵抗丁香假单胞菌的完整防御反应是必需的。
