ABSTRACT

Cyanobacteria can form nitrogen-fixing symbioses with a broad range of plant species. Unlike other plant-bacteria symbioses, little is understood about the immunological responses induced by plant cyanobionts (symbiotic cyanobacteria). Here, we demonstrated that the model plant-symbiotic cyanobacteria, Nostoc punctiforme is capable of protecting against programmed cell death (PCD) when induced in Arabidopsis thaliana suspension cell cultures. We also profiled the early transcriptomic changes that were induced in response to conditioned medium (CM) from N. punctiforme cell cultures. Interestingly, the reduction in PCD was preceded by the induction of genes associated with defence and immunity, the most striking of which were a number of WRKY-family transcription factors. Down-regulated genes included those involved in the regulation of cell growth and differentiation. This work is the first to show that a cyanobiont can affect plant PCD and provides a useful transcriptome resource for studying early plant cell responses to symbiotic cyanobacteria.

摘要

蓝细菌可以与多种植物形成固氮共生酶。与其他植物细菌共生酶不同，人们对由植物蓝藻类（共生蓝细菌）诱导的免疫反应知之甚少。在这里，我们证明了当在拟南芥悬浮细胞培养物中诱导时，模型植物共生蓝藻（点状点菜）能够防御程序性细胞死亡（PCD）。我们还分析了响应点状猪笼草条件培养基（CM）诱导的早期转录组学变化细胞培养。有趣的是，在PCD降低之前是诱导了与防御和免疫相关的基因，其中最引人注目的是许多WRKY家族转录因子。下调的基因包括那些参与细胞生长和分化调控的基因。这项工作是第一个表明氰基苯醌可以影响植物PCD的方法，并为研究早期植物细胞对共生蓝细菌的反应提供了有用的转录组资源。