Abstract: Phyllosphere and rhizosphere of plants are two unique and complex ecosystems with rich microbial components,and play an important role in promoting plant growth,enhancing plant disease resistance and stress resistance.Over the past decades,rhizosphere attracted many microbiologists and botanists,especially some research progresses were achieved at the aspects of rhizospheric microorganisms in promoting plant growth and enhancing the effect and mechanism of plant disease resistance.Comparatively speaking,the study on phyllosphere microorganisms was much more behind that on rhizospheric microorganisms.Initially,the study on phyllosphere microorganisms was focused on plant pathogenic microorganisms,so the progress of researching phyllosphere microorganisms was slow due to the limitation of technical conditions.The research on phyllosphere microorganisms was developed rapidly since the 21st century along with the development of molecular biological technique,especially the application of high-throughput sequencing technology.Recently,numerous studies proved that only a few of phyllosohere microorganisms were pathogenic,and most of them benefited plants by improving nutrients,promoting plant growth,and improving disease and stress resistance,thus a very important role of structuring plant communities and sustaining their functions was played.The objectives of this review are as follows: ① To introduce the definition of phyllosphere and the development of the methodology related to phyllosphere microorganisms as well as their biological functions and mechanisms;and ② To provide future perspectives in understanding microorganisms.

Key words: phyllosphere, microorganism, community structure, endophyte, epiphyte, biological nitrogen fixation