Donn Suzanne, Kirkegaard John A, Perera Geetha, Richardson Alan E, Watt Michelle
CSIRO Plant Industry, GPO Box 1600, Canberra, ACT, 2601, Australia.
Environ Microbiol. 2015 Mar;17(3):610-21. doi: 10.1111/1462-2920.12452. Epub 2014 May 7.
The gap between current average global wheat yields and that achievable through best agronomic management and crop genetics is large. This is notable in intensive wheat rotations which are widely used. Expectations are that this gap can be reduced by manipulating soil processes, especially those that involve microbial ecology. Cross-year analysis of the soil microbiome in an intensive wheat cropping system revealed that rhizosphere bacteria changed much more than the bulk soil community. Dominant factors influencing populations included binding to roots, plant age, site and planting sequence. We demonstrated evolution of bacterial communities within the field rhizosphere. Early in the season, communities tightly bound to the root were simplest. These increased in diversity with plant age and senescence. Loosely bound communities also increased in diversity from vegetative to reproductive plant stages but were more stable than those tightly bound to roots. Planting sequence and, to a lesser extent, wheat genotype also significantly affected rhizosphere bacteria. Plasticity in the rhizosphere generated from crop root system management and genetics offers promise for manipulating the soil ecology of intense cereal systems. Analyses of soil microbiomes for the purpose of developing agronomic benefit should include roots as well as soil loosely adhered to the roots, and the bulk soil.
当前全球小麦平均产量与通过最佳农艺管理和作物遗传学所能达到的产量之间差距巨大。这在广泛使用的集约小麦轮作中尤为显著。人们期望通过调控土壤过程，尤其是那些涉及微生物生态学的过程，来缩小这一差距。对集约小麦种植系统中土壤微生物组的跨年分析表明，根际细菌的变化远大于土壤整体群落。影响种群的主要因素包括与根的结合、植株年龄、地点和种植顺序。我们证明了田间根际细菌群落的演变。在生长季节早期，紧密结合在根上的群落最为简单。随着植株年龄增长和衰老，这些群落的多样性增加。从营养生长阶段到生殖生长阶段，松散结合的群落多样性也增加，但比紧密结合在根上的群落更稳定。种植顺序以及在较小程度上小麦基因型也显著影响根际细菌。通过作物根系管理和遗传学在根际产生的可塑性为调控集约谷物系统的土壤生态带来了希望。为实现农艺效益而对土壤微生物组进行分析时，应包括根系以及松散附着在根上的土壤和土壤整体。
