Interactions between a vesicular-arbuscular mycorrhizal fungus (Glomus intraradices) and Streptomyces coelicolor and their effects on sorghum plants grown in soil amended with chitin of brawn scales

The effect of the interaction between a vesicular-arbuscular (VA)-mycorrhiza (Glomus intraradices no. LAP8) and Streptomyces coelicolor strain no. 2389 on the growth response, nutrition and metabolic activities of sorghum (Sorghum bicolor) plants grown in nonsterilized soil amended with chitin waste was studied in a greenhouse over 8 weeks. Chitin amendment resulted in an increase in the microbial population and chitinase activity in soils. Growth of mycorrhizal G. intraradices no. LAP8 and non-mycorrhizal sorghum plants increased as compared with other treatments either in the presence or absence of S. coelicolor strain 2389. VA-mycorrhizal inoculation significantly increased the growth, photosynthetic pigments, total soluble protein and nutrient contents of sorghum compared to non-mycorrhizal sorghum. Such increases were related to increased mycorrhizal colonization. Inoculation with S. coelicolor 2389 significantly increased the intensity of mycorrhizal root colonization and arbuscular formation, but the levels of mycorrhizal infection and their beneficial effects were significantly reduced with the addition of chitin waste to the soil. Analysis of the content of total amino acids and ammonia in leaves on the basis of dry matter production showed that, in most instances, total amino acids of mycorrhizal plants were significantly higher than those of non-inoculated plants. The microflora of the rhizosphere was highly affected by mycorrhizal inoculation. Quantitative changes in acid and alkaline phosphatase activities of the roots in response to the mycorrhizal inoculation are discussed.