صبا عبد الهادي كاظم الفلوجي

This study aimed to isolate and characterize the beneficial bacteria PGPR from the soil surrounding the roots of the eggplant plant, depending on the diagnostic keys. The results of microscopic examination of bacterial cells showed that the bacterial isolates belong to Pseudomonas chlororaphis. Which were in the form of rod cells with rounded ends, negative for Gram stain, while the results of the phenotypic characteristics of the bacteria showed that they appeared on the medium Nutrient Agar round in shape, with a full edge, convex, opaque, shiny, white in color. As for King's B medium, the colonies were round, with full edge, convex, and showed a yellow fluorescence. As for the biochemical tests, it was found that the bacteria under study were negative for Indol, Starch Hydrolysis and Catalase test, while it showed a positive result in Gelatin and Oxidase test and KOH solubility and Urease. The isolates showed motility and this confirms the characteristics of the species chlororaphis. As for Bacillus thuringiensis, the results of the microscopy showed that it was gram-positive, on Nutrient Agar media, it gave white to creamy colonies. Biochemically, it was positive in the test of Catalase, Gelatin, Starch Hydrolysis, Urease and D-mannitol, and also showed susceptibility to Motility, while it gave a negative result in the test of Oxidase, Indol, KOH solubility and Voges proskauer, which confirms the characteristics of the species thuringiensis. Molecular diagnosis using PCR technique was confirmed for the isolates based on S16 rRNA gene, and two new strains were obtained for the first time in the world and deposited in (NCBI) with Accession Number: OL878994 sequence for Bacillus thuringiensis and with AccessionNumber: OL878995 for Pseudomonas chlororaphis.

This study was conducted to examine the effect of as a fertilizer on the biochemical contents of cucumber leaves Agaricus bisporus and tissues in Al-Qizuinia, Najaf during 2018 season. Six replicates (plastic pots) for each treatment were distributed randomly and the experiment was designed using complete randomize block design. There was significant differences in all observed parameters of organic fertilizer treatment in organic fertilizer treatment comparison with control treatment. The application of 1 kg of mushroom waste/ 4kg of soil as resulted in protein, carbohydrates, mineral elements (N, P, K, Ca and Mg), total chlorophyll, total phenols and plant hormones (GA , IAA) higher 3 in leaf and induced systematic resistance enzymes (POD and CAT). In the control treatment, leaves content of ABA hormone was increased, however, other chemical contents in cucumber were low as compared to organic fertilizer treatment. residue can be applied as A. bisporus fertilizer for integrated nutrient management in vegetables.

Soil bacteria form relationships with the surrounding environment from living organisms such as plants, and this relationship is often reciprocal. That is, these terrestrial bacteria will live on the organic compounds produced by the plant by the roots that will live in the area around the roots known as rhizosphere. However, after feeding it will produce a group of organic compounds that affect the growth of the plant root, which may be hormones or metabolites of secondary metabolites or other organic substances that have the ability to grow the plant root. Therefore, these relationships differ in different bacteria secretions mainly in addition to root secretions that encourage the settlement of certain types of bacteria strains. Each bacterial strain can secrete certain types of vital compounds that help stimulate or inhibit a radical part at the expense of the other, and thus have a special effect on modifying the root architecture. We carried out inoculations of the model plant Arabidopsis thaliana with a whole range of rhizobacteria and bacteria. We have shown that they do not have all the same effect on root architecture. We have identified Sp245 and Bradyrhizobium strains as having “contrasting” effects on the architecture of the root system. Analysis of our data suggests that a strain like Sp245 would affect root growth mainly due to the auxin, it secretes while the Bradyrhizobium strains use another signaling pathway.

Current study aimed to detect the spreading and virulence of leaf streak disease on wheat in some sites of Najaf province during 2020 season. Pathogenicity test, morphological, chemo-biological and molecular identification of the pathogenic bacteria was conducted. Results of field survey and the spreading of the disease were varied as the percentage of infection in was estimated between 24 and 49%, disease severity between 23.14% and 46.13%. The outcome of pathogenicity test indicated that among 47 isolates tested, 19 showed same symptoms of leaf streak disease and varied in their pathogenicity as the isolate 3 was exceeded other Xanthomonas translucens isolates and reached 46.13%. Identification tests were confirmed that the 19 isolates grown on the specific medium XTS were pale yellow with a dark brown pigment, gram negative and can grow on NA medium as the colonies appeared yellow and glossy opaque. The chemo biological tests showed that isolates were positive to KOH solubility, Aesculin hydrolysis, Catalase, Gelatin and Motility tests and negative to Hydrolysis of starch and Oxidase tests. The identification of bacteria was confirmed by PCR and based on 16S rRNA when new strain of X. translucens was registered in GenBank (NCBI) under the accession number OK287049. Results of current study were beneficial to highlight the spread of bacterial leaf streak disease on wheat in Iraq.

Pseudomonas syringae pv. lachrymans possessed a lot of factors that play an important role in the development of parasitism and growth stages of the pathogen on plant host and consider a quantitative measure of plant disease. Therefore, this study was conducted to investigate some genes responsible for the virulence factors (pilB and Sid) in isolates of P. syringaepv. lachrymans that caused angular spot disease on cucumber leaves in different areas of Najaf province. The results showed that the pilB and Sid genes were amplified in fifty-two isolates of P. syringae pv. lachrymans, forty-five isolates containedpilB gene which responsible for adhesion factors through the emergence of binds in a molecular size of 586 base pairs on agarose gel after electrophoresis. Also forty-five isolates contained Sid gene, which responsible for the siderophore factor through the emergence of binds in a molecular size of 572 base pairs on agarose gel.

The current study aimed to detect the spread of angular spot disease on cucumber leaves in different areas of Najaf province in 2017 agricultural season. Pathogenicity, biochemical and molecular diagnosis of pathogen were conducted in greenhouse and laboratory. Results of the field survey on the spread of disease were different in the infection rate ranged from 37% to 82% and the intensity of disease ranged from 30% to 60%. While the result of the hypersensitivity test on tobacco leaves and pathogenicity test on cucumber showed that 52 isolates out of 102 isolates tested were able to cause symptoms of the disease, P.s2 and P.s5 isolates were more virulence than most other isolates. The diagnostic tests were confirmed that the 52 isolates were Pseudomonas syringae pv. lachrymans. These isolates were grown on King's B agar; strains colure was initially white with a bright chromatic blue-yellowish, Gram stain negative. Oxidase, Arginine, Nitrate reduction, Indol, Aesculinhydrolys, Tartrate, Levan and Sugar fermentation tests showed that negative results. But KOH, Gelatine and Catalase and ammonia production of peptone showed that positive results. The diagnosis was confirmed by PCR for the two most virulence isolates that isolated from cucumber based on the 16S rRNA gene, which tow P. syringae pv. lachrymans strains were submitted to NCBI database and registered as new races nationally within accession number (MH279670 and MH 279671). These two strains were grouped in two different classes according to results of phylogenetic tree. The current study highlighted for the first time the incidence of bacterial angular leaf spot disease in Iraq.