轮作和连作对胡萝卜根际和非根际细菌多样性的影响

细菌是土壤最重要的组成部分,土壤细菌的群落结构对土壤的健康至关重要,可以直接影响植物的生长。胡萝卜的长年连作导致其产量低、质量差等一系列问题的发生,连作问题已成为不可忽视的问题。本研究通过HiSeq PE250高通量测序和生物信息学方法获得了玉米胡萝卜轮作种植和胡萝卜连作种植中胡萝卜根际和非根际土壤细菌的组成结构。研究结果表明,相较于胡萝卜连作,玉米胡萝卜轮作种植改变了胡萝卜根际土壤细菌的组成和群落多样性。RM.M (玉米胡萝卜轮作根际土壤样品)样品中的优势菌门为放线菌门和厚壁菌门,RM.R (胡萝卜连作根际土壤样品)的优势菌门是变形菌门;有益菌如芽孢杆菌属和根瘤菌属在玉米胡萝卜轮作种植中的胡萝卜根际富集。RM.M与RM.R的细菌类群差异显著,群落多样性较低;NRM.M(玉米胡萝卜轮作非根际土壤样品)和NRM.R (胡萝卜连作非根际土壤样)的细菌类群差异不明显,群落多样性较高。与连作根际土壤相比,轮作根际土壤中有益菌的相对丰度较大,细菌相对丰度明显增加。本研究结果对通过调节根际土壤细菌组成来保证胡萝卜产量和质量的稳定,解决连作问题具有重要的意义。

Effect of Continuous and Rotated Cropping on Bacteria Diversity in Carrots of Rhizosphere and Non-rhizosphere

Bacteria are the most important part of soil. The community structure of soil bacteria is very important for soil health and can directly affect the growth of plants. Continuous cropping of carrot leads to a series of problems such as low yield and poor quality. Obviously, continuous cropping in carot production has become a problem that cannot be ignored. The bacterial composition in rhizosphere and non-rhizosphere soil in rotation of maize and carrot and carrot continuous cropping were analyzed based on HiSeq PE250 and bioinformatics. The results illustrated that compared with consecutive cropping of carrot, the rotation of maize and carrot shifted the diversity and composition of bacteria community in rhizosphere of carrot. The dominant phyla of RM.M(the bacteria in carrot soil rhizosphere of rotation of maize and carrot) sample was Actinobacteria and Firmicutes. The dominant phyla of RM.R(the bacteria in carrot soil rhizosphere of carrot continuous cropping) sample was Proteobacteria. The bacteria population increased such as Bacillus and Rhizobium in the bacteria in carrot soil rhizosphere of rotation of maize and carrot. The community composition of soil bacteria was significantly different in RM.R and RM.M, the diversity were showed lower. The community composition of soil bacteria was not obviously different in NRM.M(The bacteria in soil non-rhizosphere of rotation of maize and carrot) and NRM.R(The bacteria in soil non-rhizosphere of carrot continuous cropping), the diversity were showed higher. Compared with the consecutive cropping rhizosphere soil, the relative abundance of the beneficial bacteria was higher, and the relative abundance of the bacteria increased obviously in the rotation cropping rhizosphere soil. It is the key to solve the continuous cropping problem by regulating the composition of rhizosphere soil bacteria to ensure the stable yield and quality of carrot. The results had great significance to regulate the yield and quality of carrots by adjusting the composition of rhizosphere soil bacteria and solve the problem of continuous cropping.