gh NEW COLLECTION OF BACTERIA

In recent times, efforts in protecting plants from insect pests are aimed at reducing the use of chemical controls, i.e., pesticides, and employing biological methods. The latter, as distinct from the chemical ones, do not contaminate the environment and agricultural products, do not accumulate in soil and water, and do not poison warm-blooded animals. Non-chemical pest control is often performed using bacteria, especially, Baccilus turingiensis (BT) that synthesizes toxins killing insects. Each strain of BT is effective against a certain insect species or a group of species. On the one hand, this definitely is an advantage of the method, because other insects (e.g., bees) are not poisoned. On the other hand, this means that scientists have to find a specific strain of BT against each kind of pests. Specialists from the Federal State Enterprise GOSNIIGENETIKA have collected 20 strains of BT obtained from natural sources in different parts of Russia. This unique collection includes strains that synthesize very unusual toxins.

Researchers all over the world hunt for new strains of BT, and their achievements are already great. Primarily, the bacterial strain that strikes butterflies and, further, BT strains against beetles, mosquitoes, locusts, protozoa, and nematodes were found. However, theoretically, there are more strains to discover, because the diversity of BTs in nature is very high. To avoid separating already known strains, one should search in areas, where plants are not treated with BT-based preparations. The Russian researchers separated bacteria from leaves, dead insects, soils, and flour. They used special culture mediums supporting only BT. Bacteria that form spores and crystals inside their cell and, therefore, can be harmful for insects were studied further.

A crystal inside the bacterial cell is, in fact, a toxin. As a rule, it consists of not only one, but several poisonous proteins, and, therefore, one stain can be effective against several insect pests. For instance, Moscow scientists have obtained two strains that simultaneously strike flour chafer, Colorado beetle, gypsy moth, and cricket (the latter was used as a test-object in search for a strain killing locust). The collectors of bacterial strains believe that potential benefits of already discovered BTs are not fully realized, because their testing was performed on only six insect species. It is very probable that other pests-targets will be found. The Russian collection is very valuable, as it includes BTs synthesizing several (2-4) kinds of crystals that are shaped as cubes, rhombi of different sizes, pyramids, and even ovals, medium and small.

Twenty strains collected by the present day produce many unusual toxins and, therefore, should be studied in a greater detail to find an efficient and productive exterminator of another pest. The diversity of BTs in Russia is very great, so, the scientists have an abundant material to work on.

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