Phyllosphere Santhakumar.M

II-M.Sc microbiologyDepartment of microbiology

Periyar university SALEM-11

Phyllosphere

Rhizosphere

Microbes colonies by all parts of the plant

MICROSCOPIC APPERIENCE OF PHYLLOSPHERE BACTERIA

ELECTRON MICROGRAPH SHOWING BACTERIA

Terms describing the location of microbial habitats related to plants:

Epiphytic = organisms growing on the surface of photosynthetic organisms

Phylloplane = leaf surfacePhyllosphere = area surrounding the leaf

Rhizoplane = root surfaceRhizosphere = area surrounding the root

Some common phylloplane micro-flora Bacteria – Pseudomonas, Bejerinckia,etc,. Fungi- Aspergillus sp,Alternaria, Cladosporium

Yeast - Caandida albicancs, Saccharomyces cerevissiae

Phylloplane consist of several types of saprotrophs,symbionts and

pathogens

THE PHYLLOSPHERE CAN BE FURTHER SUBDIVIDED INTO :

Caulosphere (stems)Phylloplane (leaves)

Anthosphere (flowers)

Carposphere (fruits)

Most plants host diverse communities of microorganisms including bacteria, fungi, archaea, and protists

PHYLLOSPHERE The leaf – surface is termed as phylloplane

and the zone on leaves inhabited by the micro-orgagisms is called phyllosphere.

The term phyllosphere was coined by the Dutch microbiologist,Ruinen.J.1961 from her observations on indonesian forest vegetation where thick microbial epiphytic associations exits on leaves. In puerto Rico,

The phyllosphere is a term used in microbiology to refer to the total above-ground portions of plants as habitat for microorganisms.

The establishment of flora on the leaf – surface aided by cuticle . Waxes and appendages helps in providing anchorage to the micro-organisms

The leaves surfaece normally consistts of some microbial population

In general apart from nitrogen –fixing bacteria ilke azotobacter, other genera such as Pseudomonas,Pseudobacterium, Phytomonas, Erwinia, Sarcina and other unidentified ones have been encountered on plant surface, especially on leaf surface .

The dominant and useful microorganisms on the leaf surfaces in the forest vegetation indonesia happened to to nitrogen fixating bacteria such as Beijerinckia and Azotobacter.

Anabaena Calothrix Nostoc Scytonema

and Tolypothrix

Nitrogen –fixing Bacteria

Nitrogen –fixing Blue

Green Algae

Nitrogen –fixing Bacteria and Blue Green Algae - Phyllosphere

Azotobacter Rhizobium Pseudomonas Pseudobacteriu

m Phytomonas Erwinia and Sarcina

SOME OF THE FUNGI AND ACTINOMYCETES

Aspergillus Alternaria Cercospora Cryptococcus Candida Cladosporium Penicillium Fusarium Colletotrichum Verticillium

Actinomyces streptomyces

FUNGUS ACTINOMYCETES

Research into the characteristics of microbial life in the phyllosphere is of great commercial importance to the agricultural industry for two reasonsFirst, 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.

BIOCHEMICAL REACTION IN THE PHYLLOSPERE

Leaf surface microorganisms may perform an effctive function in controlling the spread of air- born pathogen on the surface of leaves and pods results in the formation of a substance referred to as phytoalexin.

Alternatively the phytoalexin may be normally present in plants and the concentration of such a substance may rise markedly in response to microbial infection.

The term phytoalexin is derived from Greek phyto meaning plant and alexin meaning warding – off compound.

The fungal spores produce a chemical substance or substance which are active in inducing the production of phytoalexins by the host as a defence reaction .

Some of the known phytoalexins

S,NO PLANT INCITANTS PHYTOALEXIN

1. Soya bean (Glycine max)

Phytopthora sojae Hydroxyphaseolin

2. Potato(Solanum

tuberosum)

Phytopthora infestans

Solanine

3. Pea(Pisum sativum)

Penicillium expansum

Pisatin

4. Tobacco(Nicotiana tabacum)

Pseudomonas Solanacearum

Scopolin

5. Apple (Pyrus malus)

Venturia inaequalis Phloridzin

MICROBIAL COMMUNITIES ON LEAVES

The microbial communities of leaves are diverse and include many different genera of bacteria, filamentous fungi, yeasts, algae, and, less frequently, protozoa and nematodes. Filamentous fungi are considered transient inhabitants of leaf surfaces, being present predominantly as spores, whereas rapidly sporulating species and yeasts colonize this habitat more actively (1). Bacteria are by far the most abundant inhabitants of the phyllosphere.