Truyens S, Beckers B, Thijs S, Weyens N, Cuypers A, Vangronsveld J
Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium.
Plant Biol (Stuttg). 2016 May;18(3):376-81. doi: 10.1111/plb.12415. Epub 2015 Nov 25.
Trans-generational adaptation is important to respond rapidly to environmental challenges and increase overall plant fitness. Besides well-known mechanisms such as epigenetic modifications, vertically transmitted endophytic bacteria might contribute to this process. The cultivable and total endophytic communities of several generations of Arabidopsis thaliana seeds harvested from plants exposed to cadmium (Cd) or not exposed were investigated. The diversity and richness of the seed endophytic community decreased with an increasing number of generations. Aeromicrobium and Pseudonocardia were identified as indicator species in seeds from Cd-exposed plants, while Rhizobium was abundantly present in both seed types. Remarkably, Rhizobium was the only genus that was consistently detected in seeds of all generations, which suggests that the phenotypic characteristics were more important as selection criteria for which bacteria are transferred to the next plant generation than the actual genera. Production of IAA was an important trait for endophytes from both seed types, while ACC deaminase activity and Cd tolerance were mainly associated with seed endophytes from Cd-exposed plants. Understanding how different factors influence the seed endophytic community can help us to improve seed quality and plant growth through different biotechnological applications.
跨代适应对于快速应对环境挑战和提高植物整体适应性至关重要。除了表观遗传修饰等知名机制外，垂直传播的内生细菌可能也有助于这一过程。对从暴露于镉（Cd）或未暴露于镉的植物收获的几代拟南芥种子的可培养内生菌群落和总内生菌群落进行了研究。种子内生菌群落的多样性和丰富度随着代数的增加而降低。在暴露于镉的植物种子中，气微菌属和假诺卡氏菌属被鉴定为指示物种，而两种种子类型中均大量存在根瘤菌属。值得注意的是，根瘤菌属是在所有世代的种子中均能持续检测到的唯一属，这表明表型特征作为细菌转移到下一代植物的选择标准比实际的属更为重要。吲哚-3-乙酸（IAA）的产生是两种种子类型内生菌的重要特征，而1-氨基环丙烷-1-羧酸（ACC）脱氨酶活性和镉耐受性主要与暴露于镉的植物种子内生菌有关。了解不同因素如何影响种子内生菌群落有助于我们通过不同的生物技术应用提高种子质量和植物生长。
