Effects of soil types on phyllosphere microbial community structure and function of hyperaccumulator Sedum alfredii
Phyllosphere microorganisms play important roles in promoting plant growth and resisting biotic and abiotic stresses.Nevertheless,there is a lack of knowledge on the phyllosphere microbial community structure and function of environment-specific plants,especially heavy metal-hyperaccumulating plants.In the present study,16S rRNA high-throughput sequencing technology was used to explore the phyllosphere microbial community structure and function of the cadmium(Cd)hyperaccumulating ecotype(HE)and non-hyperaccumulating ecotype(NHE)of Sedum alfredii grown in red soil,purple soil,paddy soil and purplish clayey soil.The results showed that in purplish clayey soil and paddy soil,the relative abundances of Actinobacteria and Nocardia microorganisms in the phyllosphere of S.alfredii were higher than those in red soil and purple soil,whereas the relative abundances of Proteobacteria,Bacteroidetes and Chloroflexi microorganisms in the phyllosphere of S.alfredii grown in red soil and purple soil were higher than those in purplish clayey soil and paddy soil.In different soils,the relative abundances of Nocardia,Sphingomonas and Methylobacterium microorganisms in HE were higher than those in NHE.The soil type and ecotype significantly affected the phyllosphere microbial community structure of S.alfredii,and the soil type was the greatest contributor,accounting for 28.17％of the variation.The co-occurrence networks of the phyllosphere microorganisms of S.alfredii grown in paddy soil and red soil were more complex than those in purplish clayey soil and purple soil.Moreover,compared with those in NHE,the co-occurrence networks in HE were more complex in all the soils.PICRUSt2-based functional prediction analysis showed that the soil type significantly affected the relative abundances of glutathione metabolism,D-glutamine and glutamate metabolism,and bacterial chemotaxis pathways in the phyllosphere microorganisms of S.alfredii(p＜0.01),whereas in different soils,the relative abundances of carbohydrate metabolism(citrate cycle)and amino acid metabolism(glutathione metabolism,phenylalanine metabolism,cysteine and methionine metabolism)pathways in the phyllosphere microorganisms of HE were significantly higher than those in NHE(p＜0.01).Taken together,the soil type significantly affects the structure and function of the phyllosphere microbial community of S.alfredii,and the phyllosphere microorganisms in HE are more resistant to Cd stress than those in NHE.
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