Advances in Microbial Toxin Research and Its Biotechnological Exploitation

Microbial toxins are secondary metabolites that accumulate in the organism and, to a large extent, are metabolically inactive towards the organism that produces them. The discovery of penicillin, a secondary metabolite of Penicillium notatum West (= P. chrysogenum Thom), in 1929 marked a milestone in the development of antibiotics (microbial toxins). In the intensive studies that followed this discovery, scientists chemically characterized several new molecules (toxins) from secondary metabolites of microbes, some having a definite function in causing pathogenesis in plants. Toxins are also known to playa significant role in inciting animal (human) and insect diseases and as plant growth regulators. Many common toxins have also been isolated from different microbes exhibiting a wide spectrum of biological activity. Toxins are broadly divisible into several characteristic groupings - polyketides, oxygen heterocyclic compounds, pyrons, terpenoidS, amino acids - diketopiperazines, polypeptides etc. Recent research has indicated that these toxins play an important role in plant pathogenesis, disease epidemics, plant breeding, biological control of plant pathogens and insect pests, induced resistance, plant-pathogen interactions etc. Toxins produced by weed pathogens are exploited as lead molecules in developing environmentally friendly herbicides.

Inhalt
A Chemical Approach for Elucidating the Molecular Interaction of Host-Specific AK-toxin, with Japanese Pear.- Beauvericin: Chemistry, Biology and Significance.- Suppressor and Elicitor-Activities of Magnaporthe grisea Toxin in Rice Leaves.- Toxinogenesis of Fusarium graminearum, Clonal Variability and Influence of Substrate and Agrochemicals.- The Aflatoxins: Evolution, Function and Prospects for Control.- Oxygen Activation by Fungal and Bacterial Toxins.- Theromoresponsive Phytotoxin Production in Plant Pathogenic Bacteria.- Cerato-ulmin, a Toxin Produced by the Pathogens of the Dutch Elm Disease.- Lipopeptide Secondary Metabolites from the Phytopathogenic Bacterium Pseudomonas syringae.- Toxicity of Syringomycins and its Pathological Significance.- Structural Diversity of Lichen Metabolites and Their Potential Use.- Algal and Cyanobacterial Metabolites as Agents for Pest Management.- Engineering Disease Resistance in Plants Using Phytotoxins as Molecular Stooges.- Inhibition of Ceramide Synthesis in Plants by Phytotoxins.- Advances in Molecular Biology of Phytotoxin Production and its Involvement in Plant Pathogenesis.- Insecticidal Proteins of Bacillus Thuringiensis and Their Application in Agriculture.