PDF(Pubmed)
Abstract：
The complex evolutionary history of wheat has shaped its associated root microbial community. However, consideration of impacts from agricultural intensification has been limited. This study investigated how endogenous (genome polyploidization) and exogenous (introduction of chemical fertilizers) factors have shaped beneficial rhizobacterial selection. We combined culture-independent and -dependent methods to analyze rhizobacterial community composition and its associated functions at the root-soil interface from a range of ancestral and modern wheat genotypes, grown with and without the addition of chemical fertilizer. In controlled pot experiments, fertilization and soil compartment (rhizosphere, rhizoplane) were the dominant factors shaping rhizobacterial community composition, whereas the expansion of the wheat genome from diploid to allopolyploid caused the next greatest variation. Rhizoplane-derived culturable bacterial collections tested for plant growth-promoting (PGP) traits revealed that fertilization reduced the abundance of putative plant growth-promoting rhizobacteria in allopolyploid wheats but not in wild wheat progenitors. Taxonomic classification of these isolates showed that these differences were largely driven by reduced selection of beneficial root bacteria representative of the Bacteroidota phylum in allopolyploid wheats. Furthermore, the complexity of supported beneficial bacterial populations in hexaploid wheats was greatly reduced in comparison to diploid wild wheats. We therefore propose that the selection of root-associated bacterial genera with PGP functions may be impaired by crop domestication in a fertilizer-dependent manner, a potentially crucial finding to direct future plant breeding programs to improve crop production systems in a changing environment.
摘要：
小麦的复杂进化史塑造了其相关的根微生物群落。然而,对农业集约化影响的考虑是有限的。这项研究调查了内源性(基因组多倍体化)和外源（引入化学肥料）因素形成了有益的根瘤菌选择。我们结合培养无关和依赖的方法，从一系列祖先和现代小麦基因型中分析根际细菌群落组成及其在根-土壤界面的相关功能，在添加和不添加化肥的情况下生长。在受控的盆栽实验中，施肥和土壤隔室(根际，根际平面）是影响根际细菌群落组成的主要因素，而小麦基因组从二倍体到异源多倍体的扩展导致了下一个最大的变异。对植物生长促进（PGP）性状进行测试的根际平面衍生的可培养细菌集合表明，施肥降低了异源多倍体小麦中推定的植物生长促进根际细菌（PGPR）的丰度，但在野生小麦祖细胞中却没有。这些分离株的分类学分类表明，这些差异很大程度上是由于对代表异源多倍体小麦中类杆菌门的有益根部细菌的选择减少所致。此外，与二倍体野生小麦相比，六倍体小麦中支持的有益细菌种群的复杂性大大降低。因此，我们建议选择具有PGP功能的根相关细菌属可能会受到作物驯化的影响，这是一个潜在的关键发现，可以指导未来的植物育种计划，以改善不断变化的环境中的作物生产系统。
