Comparison Of Rhizosphere Microbiome Of Three Different Photosynthetic Types Of Flaveria

The genus Flaveria is a genus in the family Compositae.Flaveria not only contains C3 and C4 species but also many C3-C4 photosynthetic intermediates.Flaveria grows in a wide range of habitats.It is found in many places of the world.Because of its physiological,biochemical and metabolic characteristics,it grows in mineral and salt rich environment and has a very strong growth ability.Their roots are well developed and beneficial to its absorption of nutrients in barren areas.Flaveria has strong saline-alkali and barren tolerance.In some countries and regions,the genus Flaveria contains three different light and types of plants,which has great value in studying the evolutionary mechanism of plant photosynthesis.There are many undefined interactions between rhizosphere microorganisms and plants.The plants secrete products,such as carbon sources and nitrogen sources through their roots.These are used to attract the accumulation of microbes in rhizosphere space.Microbial communities that are highly enriched in rhizosphere space also assist plants in providing the nutrients needed for life activities and the absorption of metal ions.The purpose of this project is to study whether there is a connection between plant photosynthetic pathways and rhizosphere microbes.Firstly,the rhizosphere microbiomes of three different photosynthetic of Flaveria such as Flaveria bidentis?C₄?,Flaveria robusta?C₃?and Flaveria ramosissima?C₃-C₄?were analyzed grown under normal CO₂ environment?380ppm?.Low CO₂ is proposed to be the driving force of C₄ evolution,and there are significant differences in the growth of C₃ plants and C₄ plants under low CO₂.We also conducted parallel analysis of the rhizosphere microbial composition when these three species grown under low CO₂?100ppm?The rhizosphere soil was collected at 13-14 weeks,the 16s rRNA sequence was sequenced,and the obtained data were analyzed by bioinformatics softwares.The most abundant strain in all samples was Proteus,in which the?-Proteus of Proteus had little change in different CO₂ treatment,but?-Proteus had obvious difference between two CO₂ treatment and more in the rhizosphere of C₄ plants.When treated with low CO₂?100 ppm?,the species composition of F.ramosissima?C₃-C₄?rhizosphere organisms shifted tremendously which more like the one of F.robusta?C₃?,while under normal CO₂,it is more lie F.bidentis?C₄?.When considering the significantly changed microorganisms,the C₃-C₄ intermediate F.ramosissima and C₃ photosynthetic type F.robusta had more significantly different flora under low CO₂.Under low CO₂,we found some species were specific to a certain photosynthetic type:Acetobacteraceae,Rhodobiaceae,Sneathiellaceae,Gemmatimonadaceae,Nannocystaceae were specific to the C₃-C₄ intermediate F.ramosissima and Dermacoccaceae was specific to C₄ photosynthetic type F.bidentis.In the prediction of microbial gene function,the genes related to amino acid production and transport in rhizosphere microbes,the genes related to energy transfer and the genes involved in proteins secretion were highly expressed in all samples,while expression of related to carbon fixation were different in different photosynthetic types.The results of 16s rRNA sequencing of rhizosphere microbes of three different photosynthetic types of Flaveria showed that different photosynthetic types could enrich different species of microbes in rhizosphere.The phenomenon may be related to differences in the metabolites secreted by different photosynthetic types.There were also significant differences in the rhizosphere microbial diversity of different photosynthetic types.Low CO2treatment significantly changed the rhizosphere microbial composition of the C3 photosynthetic type and C3-C4 intermediate plants,and had less effect on the microbial composition of the C4plants.Our preliminary studies showed that plants of different photosynthetic type might have co-evolved with their soil microorganisms.The next step will be to further validate with more genera.