Passera Alessandro, Follador Alessia, Morandi Stefano, Miotti Niccolò, Ghidoli Martina, Venturini Giovanni, Quaglino Fabio, Brasca Milena, Casati Paola, Pilu Roberto, Bulgarelli Davide
Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy.
Institute of Sciences of Food Production, Italian National Research Council, Via Celoria 2, 20133 Milan, Italy.
Microorganisms. 2021 Nov 19;9(11):2388. doi: 10.3390/microorganisms9112388.
Locally adapted maize accessions (landraces) represent an untapped resource of nutritional and resistance traits for breeding, including the shaping of distinct microbiota. Our study focused on five different maize landraces and a reference commercial hybrid, showing different susceptibility to fusarium ear rot, and whether this trait could be related to particular compositions of the bacterial microbiota in the embryo, using different approaches. Our cultivation-independent approach utilized the metabarcoding of a portion of the 16S rRNA gene to study bacterial populations in these samples. Multivariate statistical analyses indicated that the microbiota of the embryos of the accessions grouped in two different clusters: one comprising three landraces and the hybrid, one including the remaining two landraces, which showed a lower susceptibility to fusarium ear rot in field. The main discriminant between these clusters was the frequency of Firmicutes, higher in the second cluster, and this abundance was confirmed by quantification through digital PCR. The cultivation-dependent approach allowed the isolation of 70 bacterial strains, mostly Firmicutes. In vivo assays allowed the identification of five candidate biocontrol strains against fusarium ear rot. Our data revealed novel insights into the role of the maize embryo microbiota and set the stage for further studies aimed at integrating this knowledge into plant breeding programs.
本地适应的玉米种质（地方品种）是育种中营养和抗性性状的未开发资源，包括塑造独特的微生物群。我们的研究聚焦于五个不同的玉米地方品种和一个参考商业杂交种，它们对镰刀菌穗腐病表现出不同的易感性，并使用不同方法研究了这种性状是否可能与胚中细菌微生物群的特定组成有关。我们不依赖培养的方法利用16S rRNA基因一部分的代谢物条形码来研究这些样品中的细菌种群。多变量统计分析表明，种质胚的微生物群分为两个不同的簇：一个包含三个地方品种和杂交种，另一个包括其余两个地方品种，后者在田间对镰刀菌穗腐病的易感性较低。这些簇之间的主要判别因素是厚壁菌门的频率，在第二个簇中较高，并且通过数字PCR定量证实了这种丰度。依赖培养的方法能够分离出70株细菌菌株，大多数为厚壁菌门。体内试验能够鉴定出五种抗镰刀菌穗腐病的候选生物防治菌株。我们的数据揭示了关于玉米胚微生物群作用的新见解，并为旨在将这些知识整合到植物育种计划中的进一步研究奠定了基础。
