Phyllosphere

The phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms. The phyllosphere can be further subdivided into the caulosphere (stems), phylloplane (leaves), anthosphere (flowers), and carposphere (fruits). The below-ground microbial habitats (i.e. the thin-volume of soil surrounding root or subterranean stem surfaces) are referred to as the rhizosphere and laimosphere. Most plants host diverse communities of microorganisms including bacteria, fungi, archaea, and protists . Some are beneficial to the plant, others function as plant pathogens and may damage the host plant or even kill it. However, the majority of microbial colonists on any given plant have no detectable effect on plant growth or function.

Research into the characteristics of microbial life in the phyllosphere is of great commercial importance to the agricultural industry for two reasons. First, understanding the survival of plant disease-causing bacteria and fungi is vital for developing new ways to control their spread. Second, there has been a recent rise in the number of food poisoning cases associated with fruit and vegetables contaminated with bacteria, such as Salmonella and E. coli O157:H7. This is particularly true of fresh fruits and salads which are not cooked prior to consumption. Preventing these outbreaks by developing better decontamination strategies is important to protect public health. For microorganisms the phyllosphere can be considered a hostile environment however, since there is a limited availability of nutrients, strong sun irradiation and variation in water availability.

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