Munazza Gull

By Munazza Gull

Environment friendly control of plant disease is an emerging need for agriculture in the twenty‐first century. Biological control using antimicrobial producing rhizobacteria to suppress plant diseases and promote plant health offers a powerful alternative to the use of synthetic chemicals. Many studies have been conducted to identify the specific traits by which plant growth‐promoting rhizobacteria (PGPR) promote plant growth. Most of these studies were limited to examining just one or two of these traits. The plant growth‐promoting rhizobacteria produce a wide variety of antimicrobial compounds against pathogens. The addition of antagonistic antimicrobial producing bacterial strains, either individual or as mixture in combination with fungicide, significantly decreased the plant disease stress. A single PGPR strain can produce different kinds of antimicrobial defense compounds to compete pathogens. A biocontrol agent possessing multimechanism systems of defense can antagonize pathogens in a better way. This research chapter highlights the current advancements about plant‐PGPR interactions focusing on the principles and defensive mechanisms of PGPR during disease stress conditions and their potential use for the biocontrol of plant diseases. The integrated use of genetic, molecular, and ecological approaches will form the basis for significant future advances in biocontrol research against plant diseases.

Part of the book: Plant Growth

By Munazza Gull and Sondos El-Baz

Part of the book: Plasmid

By Huda Al Doghaither and Munazza Gull

Plasmids are genetic elements of DNA molecules in the form of small circles present within the bacterial cell cytoplasm outside the bacterial chromosome. Because they are separate from the chromosome, they reproduce independently. However, plasmids are bound to multiply in the cell by multiplying the chromosome. Plasmids differ in size and number of copies in the cell. Plasmids carry genes that add to the cell additional properties, but they are not necessary for cell life and do not affect cell vitality. Some chemicals can remove plasmids from the cell by stopping their proliferation. By bacterial cell multiplication, the number of plasmids decreases until bacterial cells free from the plasmids are obtained. Plasmids are used in the techniques and research of genetic engineering and gene therapy by gene transfer to bacterial cells or to cells of superior organisms, whether other plants, animals, or other living organisms, to improve their resistance to diseases or to improve their growth rates or to improve any other required traits.

Part of the book: Plasmid