Neubauer Anna, Iniesta-Pallarés Macarena, Álvarez Consolación, Bailly Aurélien, Szövényi Péter, Mariscal Vicente
Department of Systematic and Evolutionary Botany, University of Zurich, 8008 Zurich, Switzerland.
Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland.
J Exp Bot. 2025 Sep 17;76(14):3943-3953. doi: 10.1093/jxb/eraf197.
While symbiotic plant-cyanobacteria interactions hold significant potential for revolutionizing agricultural practices by reducing the application of artificial nitrogen fertilizers, the genetic underpinnings of the symbiotic interaction between the plant host and the cyanobiont remain poorly understood. In particular, the molecular mechanisms through which host plants induce the formation of motile cyanobacterial filaments (hormogonia), essential for colonization and initiation of symbiosis, are not well characterized. In this study, we present a novel yet objective method for quantifying hormogonia induction, addressing limitations of traditional qualitative approaches. We have developed a reporter strain of Nostoc punctiforme PCC 73102 capable of quantifying hormogonia induction in response to diverse biotic and abiotic stimuli. This reporter strain, generated via triparental mating conjugation transformation, contains the promoter sequence of prepilin pilA fused to a green fluorescent protein (GFP) and enables quantitative and high-throughput monitoring of hormogonia induction using a microplate reader. Our innovative approach, employing a cyanobacterial hormogonia reporter strain, allows high-throughput screening of the hormogonia-inducing effect of a wide array of environmental and plant signals. This method is expected to greatly advance our understanding of the genetic determinants underpinning plant-cyanobacteria symbioses.
虽然共生植物-蓝细菌相互作用在通过减少人工氮肥施用来革新农业实践方面具有巨大潜力，但植物宿主与蓝细菌共生相互作用的遗传基础仍知之甚少。特别是，宿主植物诱导运动性蓝细菌丝状体（藻殖段）形成的分子机制尚未得到充分表征，而藻殖段对于共生的定殖和起始至关重要。在本研究中，我们提出了一种新颖且客观的方法来量化藻殖段诱导，解决了传统定性方法的局限性。我们构建了一种点状念珠藻PCC 73102的报告菌株，能够量化对多种生物和非生物刺激的藻殖段诱导。该报告菌株通过三亲本交配接合转化产生，包含与绿色荧光蛋白（GFP）融合的前菌毛蛋白pilA的启动子序列，并能够使用微孔板读数器对藻殖段诱导进行定量和高通量监测。我们采用蓝细菌藻殖段报告菌株的创新方法，能够对多种环境和植物信号的藻殖段诱导效应进行高通量筛选。预计该方法将极大地推进我们对植物-蓝细菌共生关系遗传决定因素的理解。
