The plant growth-promoting rhizobacteria (PGPR) application could reduce the use of synthetic fertilizers and increase the sustainability of crop production. Halophilic bacteria that have PGPR characteristics can be used in different environmental stresses. Two different strains isolated, purified, characterized as a PGPRs and phylogenetic identification using 16sRNA which was revealed to be closest matched at 99% with Bacillus halotolerans and Lelliottia amnigena. The isolates possessed plant growth promoting properties as exopolysaccharides (EPS) and indole acetic acid (IAA) production, Bacillus halotolerans had the ability to fix elemental nitrogen and the two strains have the ability to P-solubilization. Furthermore, the strains were evaluated in alleviation of different levels of salt stress on wheat plant at two experiments (Pots and a Field). Strains under study conditions significantly increased the plant height, straw dry weight (DW g plant -1 ), spike number, 1000 grain DW recorded 31.550 g with Lelliottia amnigena MSR-M49 compared to uninoculated and other strain in field, grain yield recorded 2.77 (ton fed -1 ) with Lelliottia amnigena as El-Akhdar et al.; JAMB, 20(1): 44-58, 2020; Article no.JAMB.54546 45 well as N% and protein content in grains recorded 1.213% and 6.916 respectively with inoculation with Lelliottia amnigena, also, spikes length, inoculated wheat show reduction in both proline accumulation in shoots and roots especially with Lelliottia amnigena recorded 2.79 (mg g -1 DW), inoculation significantly increased K + in root-shoot, K + /Na + in root-shoot and reduced Na + in rootshoot compared with control. This confirmed that this consortium could provide growers with a sustainable approach to reduce salt effect on wheat production. Original Research Article

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Salinity is one of the most vicious environmental factors controlling the productivity of crop plants as most of the crop plants are sensitive to salinity affected by high concentrations of salts in the soil. The objective of this study was to evaluate the influence of the inoculation with the encapsulated and liquid culture of three halo-tolerant plants growth-promoting rhizobacteria (PGPR) strains of Paenibacillus polymyxa MSRH5, Bacillus nakamurai MSRH1 and Bacillus pacificus MSR H3 on the growth and yield of wheat (Triticum aestivum L.). The three strains MSRH1, MSRH3 and MSR H5 were characterized as salt-tolerant bacteria. P. polymyxa MSRH5 had nitrogen fixation ability while B. nakamurai MSRH1 and B. pacificus MSRH3 were able to solubilize phosphate and K respectively. All strains can produce indole acidic acid (IAA) and exopolysaccharides (EPS) under saline conditions. Encapsulated beads were observed under Scanning Electron Microscope (SEM). Colonization of encapsulated bacteria on the root of the wheat plant was studied by Transmission Electron Microscopy (TEM). Under soil salinity conditions in two consecutive field tries, results cleared that strains in two forms succeed to colonize the plant root, the reduction in shoot proline was 35.8% with capsules inoculation as well as improved relative water content (%) to 60.57% and improved the electrolyte leakage recorded 18.1% respectively compared to control. Generally, halo-tolerant PGPR inoculation increased DHA (?), acidic and alkaline phosphatase activities compared to control, inoculation with capsules exhibited a reduction in catalase enzymes 46.00%, 37.5% in ascorbate peroxidase and 40% in superoxide dismutase respectively in shoots of the wheat plant. There is a significant increase in all yield parameters, the highest plant height 115.8 cm, spike length 21 cm and 1000 grains 71.3 g respectively recorded with capsules inoculation, it had considerable effects on the content of N, P, K and Na in shoots of wheat plants and reduced the value of Na/K ratio in all treatments inoculated compared to un-inoculated wheat plant.

The demand for chemical fertilizers in agriculture has increased to deal with the present global population increase. However, the excessive use of chemical fertilizers can be reduced by applying biofertilizers as an eco-friendly tool. Plant growth-promoting rizobacteria (PGPR) has an essential need in terms of fertilizer savings and promoting plant yield. Here, we study the effect of using three (PGPR) bacterial strains “Bacillus nakamurai MSRH1, Bacillus pacificus MSRH3, Paenibacillus polymyxa MSRH5”, integrated with chemical fertilizers (40, 60, 80, 100% need based NPK) on vegetative growth, yield production, and quality of table grapes ‘Flam Seedless’ grown in sand soil during two successive seasons of 2020 and 2021, with a preliminary trial season in 2019. Our results show that amending grapes with NPK in combination with the consortium of three strains led to significant improvement in colonized vines compared to a single application of 100% NPK. Results showed that bacterial consortium combined with 80% and 60% NPK mineral fertilizer had more positive effects than un-inoculated vines in growth parameters, cluster characteristics, yield/vine and berry quality in the two growing seasons. Besides, N, P and K concentrations of leaf petiole, total leaf chlorophyll content, and carbohydrates in canes were significantly enhanced by bacteria consortium with 80% and 60% PK chemical fertilizers. PGPR significantly increased total bacterial count, N2-fixing, P- solubilizing and K-solubilizing bacteria in soil treated with the three strains of bacteria plus mineral fertilizer. In addition, dehydrogenase and phosphatase activity in the rhizosphere soil were also increased in treatments inoculated with strains plus mineral fertilizer. The field study results showed that PGPR approach has potential and can be considered as a crop management strategy to increase the yield and quality of grapes, reduce chemical fertilization and subsequent environmental pollution, and could be useful in terms of sustainable production.

Tomato (Lycopersicon esculentum Mill.) is considered a main contributor to food of humans. It is mainly grown in all countries whether in fields or protected cultures. Tomato is considered one of the most essential vegetable crops. It is grown in Egypt in different seasons throughout the year basically in newly reclaimed desert lands. Root-knot nematodes, Meloidogyne spp. are considered is one of the most economically important pest because its damage, infection level , wide host range and minimize the quality and quantity of the crop . This study can be summarized as follows : 1-Experimentally, the culture broth of four bacterial isolates i.e. P. fluorescens, A. brasilense, A. chroococcum & B. megaterium were used to test their effect on egg hatching and juveniles mortality of Meloidogyne spp. under room temperature after 24,48,72 & 168h of exposure. 2-The present results exhibited that all bacterial isolates affected nematode eggs and juveniles especially B.megaterium where fulfilled the least percentage of egg hatching and the highest percentage of juveniles mortality after 168 h of exposure by 17.3 & 92%, respectively compared to control. 3-This has been inferred through doing an experimentally test for this bacterium on King's B medium in petri dishes and incubated it for 48 h at 27ċ where the results exhibited that this bacterium had the ability to analyze the protein existed in this medium by exhibiting a clear halo zone around the bacterial colony. 4-The same four bacterial isolates were used as a culture broth at three application times (one week before, at the same time and one week after) of nematode inoculation to study their effect on Meloidogyne spp. on tomato plants under greenhouse conditions. 5-These results exhibited that all bacterial isolates significantly affected the nematode and vegetative parameters especially during adding them at one week before of ,nematode inoculation where B.megaterium fulfilled the highest reduction percentages of nematode parameters and highest increase in vegetative parameters , antioxidant enzymes and pigments concentrations due to secrete natural compounds which act against the nematode and promoting the plant growth. 6-Other experiment was done under greenhouse conditions by applying B.megateriumin two forms i.e. liquid and capsules contained and uncontained humic acid at the rate of 3,5,10 ml or capsules /plant to know which two forms are the most effect . 7-These present results exhibited that both forms fulfilled a significant effect in inhibiting the nematode parameters and increasing the vegetative parameters of plant, but using the capsules is better than a liquid form because it supplies with the permanent protection for bacteria from adverse conditions as well as slowly release of the bacteria which had a longer effect in soil.