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The population growth is one of the most important global problems that researchers must overcome. So, application of plant growth promoting rhizobacteria (PGPR) can play a significant role in enhancing the agricultural production through facilitating water and nutrient uptake for plants under various conditions as an important and alternative strategy to overcome overpopulation all over the world. Plant growth promoting rhizobacteria can used as low-cost and environmentally safe biofertilizer to improve crop growth and development by regulating hormonal balance, maintaining nutrients and producing plant growth regulators, however, the chemical fertilizers can harm the ecosystem and human health severely. PGPR treatments may positively affect physiological, biochemical and anatomical features resulting in improve various morphological characters such as number of leaves, leaf area and stem height. Additionally, chlorophyll a and b, carotenoids, relative water content (RWC), antioxidant enzymes and plant hormones as well as crop yield were increased in many plants with the application of PGPR. Moreover, application of PGPR led to improve the anatomical characters of stems and leaves such as stem diameter, lamina thickness, phloem thickness, xylem vessels diameter and number of xylem vessels. Previous studies also reported that PGPR can mitigate the adverse effects of several biotic and abiotic stresses resulted in improve plant growth and yield in many stressed plants. This review article gives an overview on the impacts of PGPR in enhancing morphological, physio-biochemical and anatomical characters through improving the antioxidant enzymes activity, producing plant hormones and consequently crop production. [ABSTRACT FROM AUTHOR]

Xanthomonas genus causes lesions on plant leaves, stems, and fruits. Xanthomonas campestris is considered as one of the most devastating pathogens that infects pepper and tomato worldwide. Traditionally the Xanthomonas disease are controlled by using chemicals control methods that possess numerous demerits. There is a need to develop an effective and safe biocontrol strategies to control these diseases. The present work was aimed to isolate and identify Xanthomonas sp. from infected pepper plants and to develop a suitable biocontrol agent. In the present study we report four new isolates of X. axonopodis from infected pepper plants. Based on 16S rDNA homology, these isolates were identified as X. axonopodis QXP1, X. axonopodis QXP2, X. axonopodis QXP3, and X. axonopodis QXP5. These isolates were able to cause the re-infections in pepper plant. Eight strains of Streptomyces sp. were tested for their biocontrol activity against Xanthomonas isolates. Streptomyces tricolor strain HM10 exhibited potent biocontrol activity against the tested pathogens. To the best of our knowledge, this is the first report regarding the isolation X. axonopodis from pepper plants. [ABSTRACT FROM AUTHOR]