| The root-associated microbiome has a strong influence on the health and nutritional status of the plant and has contributed greatly to the biogeochemical cycle,understanding the distribution and temporal succession characteristics of the root-associated microbiome within a miniscule space is significant in crop and environment improvement.Years of research have confirmed that plants significantly affect the structural composition of their root-associated microbiome.The microbial diversity not only declines sequentially from bulk soil to rhizosphere and root,also under significantly regulated by the plant growth period.However,the dynamic selection characteristics of legumes with its root-associated microbiome members has not fully elucidated.Most of the studies related to plant growth are conducted in an indoor controlled environment,whereas under natural conditions are relatively less.In combination with the high-throughput 16 S rDNA amplicon sequencing technology,the root-associated microbiome of soybean at different growth stages under field conditions were mainly studied from the perspectives of microbial diversity and co-occurrence interaction networks.The results are as follows.Compared with bulk soil,the diversity and functional composition of soybean rhizosphere and root microbial community decreased significantly,and its succession characteristics also showed a pattern closely related to the growth phase of soybean.Under different degree of plant regulation,soybean rhizosphere and root microorganism have inconsistent succession characteristics,respectively.The establishment of rhizosphere flora mainly follows the principle of niche adaptability,while the root flora is more significantly regulated by host signals.In spite of this,the soybean rhizosphere and root flora tend to be more conservative and robust in terms of their structural composition and make the diversity more consistent,and the specific microbial groups are gradually taking the dominant position in their respective microhabitats.Driven by co-evolutionary adaptation,soybean symbiotic rhizobia occupy a dominant position in the soybean root environment.The co-occurrence patterns of bulk soil,soybean rhizosphere and root microbial communities are also determined by the type of micro-habitat and the growth stage of soybean.Soybean root system has a more complex microbial network structure than bulk soil,and is significantly related to the corresponding microbial species diversity composition.While the diversity composition of the soybean root flora tend to stabilized,the degree of interaction between different microorganisms was constantly enhanced and the network has become more connected.Affected by the soybean root system,the bulk soil microbial network also has a tighter connection in the late growth period of soybean,although there is no obvious change in the microbial diversity.Over time,there are more key species in the microbial networks of three micro-habitats dominate the network structure,different microbial species in the network also have more similar niche sharing patterns and collaborative models. |
