The induction of plant nutrient secretion systems is critical for successful pathogen infection. Some bacterial pathogens (e.g., Xanthomonas spp.) use transcription activator-like (TAL) effectors to induce transcription of SWEET sucrose efflux transporters. Pseudomonas syringae pv. tomato strain DC3000 lacks TAL effectors yet is able to induce multiple SWEETs in Arabidopsis thaliana by unknown mechanisms. Because bacteria require other nutrients in addition to sugars for efficient reproduction, we hypothesized that Pseudomonas spp. may depend on host transcription factors involved in secretory programs to increase access to essential nutrients. Bioinformatic analyses identified the Arabidopsis basic-leucine zipper transcription factor bZIP11 as a potential regulator of nutrient transporters, including SWEETs and UmamiT amino acid transporters. Inducible downregulation of bZIP11 expression in Arabidopsis resulted in reduced growth of P. syringae pv. tomato strain DC3000, whereas inducible overexpression of bZIP11 resulted in increased bacterial growth, supporting the hypothesis that bZIP11-regulated transcription programs are essential for maximal pathogen titer in leaves. Our data are consistent with a model in which a pathogen alters host transcription factor expression upstream of secretory transcription networks to promote nutrient efflux from host cells.

Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

植物营养物分泌系统的诱导对于成功感染病原体至关重要。一些细菌病原体（例如Xanthomonas spp。）使用转录激活因子样（TAL）效应子来诱导SWEET蔗糖外排转运蛋白的转录。丁香假单胞菌（Pseudomonas syringae） pv。番茄菌株DC3000缺乏TAL效应子，但能够通过未知机制诱导拟南芥中的多种SWEET 。由于细菌除了糖以外还需要其他营养素才能有效繁殖，因此我们假设假单胞菌属（Pseudomonas spp）。可能取决于分泌程序中涉及的宿主转录因子，以增加对必需营养素的获取。生物信息学分析确定了拟南芥碱性亮氨酸拉链转录因子bZIP11作为营养转运蛋白（包括SWEET和UmamiT氨基酸转运蛋白）的潜在调节剂。拟南芥中bZIP11表达的诱导下调导致丁香假单胞菌PV的生长减少。番茄菌株DC3000，而bZIP11的诱导型过表达导致细菌生长增加，支持bZIP11调控的转录程序对于叶片中最大病原体效价必不可少的假设。我们的数据与一种模型一致，在这种模型中，病原体会改变分泌转录网络上游的宿主转录因子表达，从而促进营养物质从宿主细胞中流出。

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