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Ginger is used as one of the important ingredients in traditional as well as modern medicine besides as a spice. It boosts immunity and is a rich source of many biologically active substances and minerals. Although it is a medicinally important crop, its productivity is, however, affected due to poor nutrient management and therefore it requires an adequate supply of nutrients in the form of inorganic fertilizers or organic manuring, or a mixture of both. In this context, the present study was aimed to investigate the effect of mineral fertilizers on the content of mineral elements in the ginger rhizome, on soil enzyme activity, and soil properties. Lysimeter experiments were conducted at the Institute of Genetics and Plant Experimental Biology, Kibray, Tashkent region, Uzbekistan. The experiment comprised of four treatments T1 – Control, T2 - N75P50K50 kg/ha, T3 - and T4 - N100P75K75 + B3Zn6Fe6 kg/ha. The results showed that the application of N125P100K100 kg/ha increased rhizome K content by 49%, P content by 20%, and Na content by 58% as compared to control without fertilizer. While the application of N100P75K75 + B3Zn6Fe6 kg/ha showed a significant enhancement in rhizome K, Ca, P, Mg, Na, Fe, Mn, Zn, Cu, Cr, Mo, and Si contents over the control. This treatment also improved active P content by 29%, total P content by 80%, total K content 16%, and N content by 33% content, and the activities of urease, invertase, and catalase activities as compared to control of without mineral fertilizer and control respectively. Thus the application of NPK + BZnFe at the rate of 100:75:75:3:6:6 kg/ha helps in improving macroelements and microelements in the ginger rhizome and activities of soil enzymes that helps in mineral nutrition of the rhizome.

The medicinal plants are widely used to treat diverse ailments and diseases, including gastro-intestinal symptoms, cardiovascular diseases, skin disorders, respiratory and infectious diseases, accelerating in recent years. Plants are rich in a wide variety of secondary metabolites, such as alkaloids, tannins, flavonoids, and phenolic compounds, found in vitro to have antimicrobial properties and could assist in the discovery of novel drugs. The search for novel antimicrobial compounds, especially against multidrug-resistant pathogens from aromatic and herbal plants, is an essential line of scientific research. This review attempts to summarize the in vivo studies of the antimicrobial activity of medicinal plants and their biologically active compounds. The chemical composition of biologically active compounds with antimicrobial is also addressed.

Ginger (Zingiber officinale Roscoe) is an important medicinal crop grown for its aromatic rhizome which is used as a spice, food, flavouring agent and medicine. It has been characterised for its hypoglycemic, hypotensive, antioxidant and antibiotic properties. This study was conducted to determine the impact of plant growth-promoting potential of bacterial strain Bacillus subtilis L2 on plant growth and physiological properties of ginger. The experiment was carried out in randomised block design with three replications in pot experiments. The plants were grown in greenhouse conditions for three months. The results showed that at 8 and 12 weeks after planting (WAP) bacterial inoculation increased plant height, leaf length, number of leaves per plant and leaf width. Inoculation with B. subtilis L2 significantly increased plant height by 16, 20 and 18% compared to control at 4, 8 and 12 WAP. At 8 and 12 WAP, leaf length significantly raised by B. subtilis L2 as compared to uninoculated control. B. subtilis L2 significantly increased the number of leaves per plant and leaf width by 30 and 21% respectively when comparing with non-inoculated plants at 8 WAP. The percentage increase in chlorophyll content resulted from the inoculation with B. subtilis L2 over the control was 10.5%, 15.5% and 18.4% at 4, 8 and 12 WAP respectively. It is concluded that there is a significant positive effect of inoculation with B. subtilis L2 on the growth of ginger. B. subtilis L2 strain can be used as a potential agent or bio-fertiliser for stimulation of ginger growth.

In traditional medicine of Uzbekistan, around 20% of herbal plants are used to treat various ailments, including diseases caused by pathogenic bacteria and fungi. Though conventional medicinal plants are common in Uzbekistan, many plant species potentially useful for new pharmaceuticals are less studied. They contain various biological compounds with antibacterial and antifungal activities, that could be developed into drugs. The search for novel antimicrobial compounds, especially against multidrug-resistant pathogens from aromatic and herbal plants is an essential scientific research line. However, the antimicrobial properties of several medicinally important plants from various countries are still unknown. This review aims to provide an up-to-date report on the antimicrobial activity of medicinal plants endemic to Uzbekistan widely used in traditional medicine.

Arbuscular mycorrhizal fungi (AMF) inoculation and biochar amendment has been reported to improve the growth of several crop plant, however, their role in stress amelioration individually as well as in combination has not been worked out. Limited information is available about the synergistic use of biochar and Arbuscular Mycorrhizal Fungi (AMF). Here, we investigated the synergistic effect of biochar and AMF on plant development, root architecture, the physiological performance of fenugreek (Trigonella foenum-graecum), and soil enzymatic activities. Biochar and AMF were shown to have a considerable effect on plant height, according to the data (53.3 and 66.6%, respectively), leaf number (22.5 and 45.1%), total root length (19.8 and 40.1%), root volume (32.1 and 71.4%), chlorophyll a content (26.0 and 17.8%), chlorophyll b content (50.0 and 28.9%), total chlorophyll content (30.0 and 18.1%), and carotenoid content (60.0 and 48.0%) over the control treatment. There was a considerable increase in plant height when biochar and AMF were combined together by 80.9%, total root length by 68.9%, projected area by 48.7%, root surface area by 34.4%, root volume by 78.5%, chlorophyll a content by 34.2%, chlorophyll b content by 68.4%, total chlorophyll content by 44.5%, and carotenoid content by 84.0% compared to the control. Our results recommend that the combination of biochar and AMF is advantageous in fenugreek growth, microbial biomass, and soil enzyme activities.

Drought stress is the major abiotic factor limiting crop production. Co-inoculating crops with nitrogen fixing bacteria and plant growth-promoting rhizobacteria (PGPR) improves plant growth and increases drought tolerance in arid or semiarid areas. Soybean is a major source of high-quality protein and oil for humans. It is susceptible to drought stress conditions. The co-inoculation of drought-stressed soybean with nodulating rhizobia and root-colonizing, PGPR improves the root and the shoot growth, formation of nodules, and nitrogen fixation capacity in soybean. The present study was aimed to observe if the co-inoculation of soybean (Glycine max L. (Merr.) nodulating with Bradyrhizobium japonicum USDA110 and PGPR Pseudomonas putida NUU8 can enhance drought tolerance, nodulation, plant growth, and nutrient uptake under drought conditions. The results of the study showed that co-inoculation with B. japonicum USDA110 and P. putida NUU8 gave more benefits in nodulation and growth of soybean compared to plants inoculated with B. japonicum USDA110 alone and uninoculated control. Under drought conditions, co-inoculation of B. japonicum USDA 110 and P. putida NUU8 significantly enhanced the root length by 56%, shoot length by 33%, root dry weight by 47%, shoot dry weight by 48%, and nodule number 17% compared to the control under drought-stressed. Co-inoculation with B. japonicum, USDA 110 and P. putida NUU8 significantly enhanced plant and soil nutrients and soil enzymes compared to control under normal and drought stress conditions. The synergistic use of B. japonicum USDA110 and P. putida NUU8 improves plant growth and nodulation of soybean under drought stress conditions. The results suggested that these strains could be used to formulate a consortium of biofertilizers for sustainable production of soybean under drought-stressed field conditions.

This study aimed to investigate the effects of biochar (1%, 2%, and 3%) on seed germination, plant growth, root morphological characteristics, and physiological properties of ginger (Zingiber officinale) and soil enzymatic activities. Pot experiments under greenhouse conditions at 24 °C (day) and 16 °C (night) showed after six weeks that biochar additions of 2% and 3% significantly increased seed germination, plant height, leaf length, leaf number, as well as shoot and root dry weights compared to the control. Total root length significantly increased by 30%, 47%, and 74%, with increasing biochar contents (1%, 2%, and 3%) compared to the control. Root surface area, projected area, root diameter, and root volume reached a maximum at the 3% biochar treatment. The treatment with 2% biochar significantly increased fluorescein diacetate hydrolase and phenoloxidase activities by 33% and 59% compared to the control, so did the addition of 3% biochar, which significantly increased fluorescein diacetate hydrolases, phenoloxidase, and acid and alkaline phosphomonoesterase activity in soil compared to the control. Treatment with 3% biochar increased relative water content by 8%, chlorophyll content by 35%, and carotenoid content by 43% compared to the control. These results suggest that biochar can improve the performance of the rhizome of ginger and increase the activity of soil enzymes, thereby improving soil nutrient supply.

A mineral fertiliser has positive effects in improving turmeric nutrients, soil enzymes and soil properties. The aim of this research was to study the effect of mineral fertilisers on the content of mineral elements in turmeric rhizome, soil enzymes activity and soil properties in the Tashkent Region, Uzbekistan. For the first time in Uzbekistan, the turmeric rhizome was cultivated to study the mineral elements present in the rhizome. A microplot experiment was conducted with four treatments including T1 (Control), T2 (N75P50K50 kg/ha), T3 (N125P100K100 kg/ha) and T4 (N100P75K75 + B3Zn6Fe6 kg/ha) and turmeric rhizome, which were collected for observation along with the soil samples. The analyses indicated that the NPK + BZnFe (100:75:75:3:6:6 kg/ha) treatment significantly improved minerals such as K, Ca, P, Mg and Na contents rhizome as compared to the control without fertiliser. Likewise, the maximum quantity of micronutrient content viz., Fe, Mn, Zn, Cu, Cr and Si was also recorded in turmeric rhizome treated with NPK + BZnFe (125:100:100:3:6:6 kg/ha). It showed an increase in these micronutrients in the rhizome compared to the control, followed by a low rate of NPK (75:50:50 kg/ha). The highest content in terms of total N, P, K content, humus, active phosphorus, potassium, and enzymes activity was also observed in soil with the treatment of mineral fertiliser viz., NPK + BznFe (100:75:75:3:6:6 kg/ha), which enhanced soil nutrient and enzyme activity. The NPK + BznFe (100:75:75:3:6:6 kg/ha) treatment significantly increased the active N content by 40%, total P content by 38% and total K content by 22% in comparison to the control without mineral fertiliser. Overall, it was found that NPK + BznFe (100:75:75:3:6:6 kg/ha) was significantly valuable for enhancing the total nitrogen, phosphorus, and potassium levels in the soil compared to control, which is useful for improving soil health in terms of soil enzyme and soil nutrients. Additionally, the micronutrients in turmeric rhizome were significantly enhanced when using this combination of fertiliser applications [NPK + BznFe (100:75:75:3:6:6 kg/ha)]. Therefore, this present study revealed that the NPK+BznFe (100:75:75:3:6:6 kg/ha) could produce the most significant yield of high-quality turmeric plants and improve soil properties in Uzbek soil–climate conditions.

Drought is a major abiotic factor limiting plant growth and crop production. There is limited information on effect of interaction between biochar and Arbuscular mycorrhizal fungi (AMF) on okra growth, root morphological traits and soil enzyme activities under drought stress. We studied the influence of biochar and AMF on the growth of Okra (Abelmoschus esculentus) in pot experiments in a net house under drought condition. The results showed that the biochar treatment significantly increased plant growth (the plant height by 14.2%, root dry weight by 30.0%) and root morphological traits (projected area by 22.3% and root diameter by 22.7%) under drought stress. In drought stress, biochar treatment significantly enhanced the chlorophyll ‘a’ content by 32.7%, the AMF spore number by 22.8% and the microbial biomass as compared to the control. Plant growth parameters such as plant height, shoot and root dry weights significantly increased by AMF alone, by 16.6%, 21.0% and 40.0% respectively under drought condition. Other plant biometrics viz: the total root length, the root volume, the projected area and root diameter improved significantly with the application of AMF alone by 38.3%, 60.0%,16.8% and 15.9% respectively as compared with control. Compared to the control, AMF treatment alone significantly enhanced the total chlorophyll content by 36.6%, the AMF spore number by 39.0% and the microbial biomass by 29.0% under drought condition. However, the highest values of plant growth parameters (plant height, shoot dry weight, root dry weight) and root morphological traits (the total root length, root volume, projected area, root surface area) were observed in the combined treatment of biochar and AMF treatment viz: 31.9%, 34.2%, 60.0% and 68.6%, 66.6%, 45.5%, 41.8%, respectively compared to the control under drought stress. The nitrogen content, total chlorophyll content and microbial biomass increased over un-inoculated control. The soil enzymes; alkaline phosphatase, dehydrogenase and fluorescein diacetate enzyme activities significantly increased in the combined treatment by 55.8%, 68.7% and 69.5%, respectively as compared to the control under drought stress. We conclude that biochar and AMF together is potentially beneficial for cultivation of okra in drought stress conditions.

Biochar and arbuscular mycorrhizal fungi (AMF) can promote plant growth, improve soil properties, and maintain microbial activity. The effects of biochar and AMF on plant growth, root morphological traits, physiological properties, and soil enzymatic activities were studied in spinach (Spinacia oleracea L.). A pot experiment was conducted to evaluate the effect of biochar and AMF on the growth of spinach. Four treatments, a T1 control (soil without biochar), T2 biochar alone, T3 AMF alone, and T4 biochar and AMF together, were arranged in a randomized complete block design with five replications. The biochar alone had a positive effect on the growth of spinach, root morphological traits, physiological properties, and soil enzymatic activities. It significantly increased the plant growth parameters, such as the shoot length, leaf number, leaf length, leaf width, shoot fresh weight, and shoot dry weight. The root morphological traits, plant physiological attributes, and soil enzymatic activities were significantly enhanced with the biochar alone compared with the control. However, the combination of biochar and AMF had a greater impact on the increase in plant growth, root morphological traits, physiological properties, and soil enzymatic activities compared with the other treatments. The results suggested that the combined biochar and AMF led to the highest levels of spinach plant growth, microbial biomass, and soil enzymatic activity.

Gradual depletion in soil nutrients has affected soil fertility, soil nutrients, and the activities of soil enzymes. The applications of multifarious rhizobacteria can help to overcome these issues, however, the effect of co-inoculation of plant-growth promoting rhizobacteria (PGPR) and biochar on growth andnutrient levelsin soybean and on the level of soil nutrients and enzymes needs in-depth study. The present study aimed to evaluate the effect of co-inoculation of multifarious Bradyrhizobium japonicum USDA 110 and Pseudomonas putida TSAU1 and different levels (1 and 3%) of biochar on growth parameters and nutrient levelsin soybean and on the level of soil nutrients and enzymes. Effect of co-inoculation of rhizobacteria and biochar (1 and 3%) on the plant growth parameters and soil biochemicals were studied in pot assay experiments under greenhouse conditions. Both produced good amounts of indole-acetic acid; (22 and 16 µg mL−1), siderophores (79 and 87%SU), and phosphate solubilization (0.89 and 1.02 99 g mL−1). Co-inoculation of B. japonicum with P. putida and 3% biochar significantly improved the growth and nutrient content ofsoybean and the level of nutrients and enzymes in the soil, thus making the soil more fertile to support crop yield. The results of this research provide the basis of sustainable and chemical-free farming for improved yields and nutrients in soybean and improvement in soil biochemical properties.

Medicinally important plants produce various phytochemical constituents, such as phenols, tannins, and alkaloids, which have an effect on the physiology of endophytic microbes. There is evidence that microbes living symbiotically with plants can produce similar metabolites to their hosts with similar biological activity. Endophytic microbes may contribute to plants’ natural defenses by preventing herbivores and the biocontrol of pathogens and pests due to their ability to produce the same or similar compounds to the host plants. The plant microbiome, including rhizobia and endophytic bacteria and fungi from extreme environments, is most likely to possess diverse functions that help plants to adapt to hostile environments. Many microbes and fungi isolated from medicinal plants that exhibit antibacterial activity against human pathogenic bacteria, also produce bioactive compounds with antimicrobial activities. The endophytes with antimicrobial activity produce metabolites such as celastramycins, kakadumycins, and javanicin. Several other compounds were found in endophytes with antioxidant activities, such as phenols, tannins, flavonoids, ascorbic acid, carotene, and cajaninstilbene acid. In this review, endophytes that produce biologically active metabolites will be discussed. In addition, microbial metabolites and the future research trends of using biologically active compounds for new drug discovery will also be highlighted.

An experiment was carried out to investigate the effects of different mineral fertilizers on mineral contents in turmeric rhizomes and soil enzyme activities and soil properties under field conditions in Uzbekistan. The present study is the first report on the impact of mineral fertilizers in turmeric rhizomes and soil enzymes and soil properties in Uzbekistan. The experiment was carried out with four treatments: T1—Control, T2—N75P50K50 kg/ha, T3—N125P100K100 kg/ha, and T4—N100P75K75 + B3Zn6Fe6 kg/ha. Turmeric rhizomes and soil samples were collected from field experiments at the Surkhandarya scientific experimental station of the vegetable, melon crops and potato research institute, Surkhandarya, Uzbekistan. The data showed that T3—the NPK (125:100:100 kg/ha) and T4—the NPK + BZnFe (100:75:75:3:6:6 kg/ha) treatments significantly enhanced K content by 27–21%, Ca content by 43–38%, and P content by 54–17% in turmeric rhizomes as compared to control without fertilizer. A maximum of turmeric rhizome microelements content was recorded with T4, which also resulted in improved Fe, Zn, Cu, Cr, and Mo contents in turmeric rhizomes and mineral contents of soil compared to other treatments. This treatment significantly enhanced active P content by 34%, active K content by 25%, total P content by 62%, total K content by 14%, and the activities of soil urease, invertase, catalase, and phosphatase over those in the control. The present study results suggest that the application of NPK + BZnFe (100:75:75:3:6:6 kg/ha) improves macro and micronutrient contents in turmeric rhizomes and activities of soil enzymes and physicochemical properties of soil.

There is evidence of medicinal plants having been used in the treatment of human disease caused by various pathogenic microorganisms in many countries of the world. Plants with known antimicrobial activities were used for therapeutic treatments. They contain various biological compounds which could be used in the development of novel drugs for human well-being. Their phytochemical constituents include alkaloids, saponins, tannins, flavonoids, and glycosides, which serve as defense mechanisms against various microbes including insects. These compounds may include antibacterial, antifungal, and anticancer activities. The search for new antimicrobial compounds from medicinal plants from many continents is an important line of research because of the increased number of multidrug resistance pathogenic microorganisms. However, the therapeutic ability of a number of medicinal important plants is still unknown. Considering the importance of medicinal plants as sources for antimicrobial drugs, in this review, we report on progress to date in antimicrobial activities of medicinal plants.

Understanding the symbiotic performance of rhizobia and responses of plant root systems to mineral nutrient supply will facilitate the development of strategies to enhance effective rhizobia-legume symbioses. Interactive effect of nitrogen (N), phosphorus (P), and magnesium (Mg) on the symbiotic performance of soybean (Glycine max L.) with Bradyrhizobium japonicum, nodulation, root architecture, and the N concentration in plant tissue under hydroponic conditions were studied. Plant growth was significantly higher under a high N supply combined with Mg (HNHMg) than in combination with P (HNHP), which was attributed to the interaction between N and Mg ions. The plants grown at a low N concentration combined with either high or low P or Mg (LNHP, LNHMg, LNLP, and LNLMg) showed a higher nodule dry weight compared to those grown under a high N supply. We observed that the N content in the roots and shoots of soybean plants was significantly lower under LNHP or LNLP, but it was higher under HNHMg or LNHMg, indicating that Mg promotes N acquisition by the plant tissues. Neither root nor shoot growth responded significantly to P availability regardless of the N supply. We observed significant positive relationships between the number of nodules, the N content in plant tissues and the root system architecture of soybean plants grown with a variable supply of Mg combined with N, which highlights the importance of N and Mg availability in the growth medium in regulating root system architecture and nodule formation. The number of rhizobial cells colonizing soybean roots was highest under the HNHMg treatment (6.78 × 104 CFUs/cm of root tip), followed by the HNLMg (4.72 × 104 CFUs/cm of root tip) and LNHMg (4.10 × 104 CFU/cm of root tip) treatments, and lowest under the LNLMg (1.84 × 104 CFUs/cm of root tip) nutrient conditions. The results of this study contribute to new insights for the improvement of the root system and the symbiotic performance of rhizobia inoculated on legumes, stressing the importance of a balanced supply of nutrients.

Uzbekistan is known throughout the world for its rich history of herbal plants and their use in traditional medicine. Uzbekistan significantly surpasses other regions of the world in terms of the endemism and species richness found in this country. These plants are a source for biologically active compounds that are used in pharmacological tests, with a high probability of new drug discovery. Pharmacological studies have confirmed that plant extracts and individual compounds have various biological activities such as hepatoprotective, dermatological, antimicrobial, antiviral, anti-ulcer, antioxidant, neuroprotective, and antiinflammatory properties. In the present review, an attempt was made to provide an up-to-date report on the diversity of medicinal plants widely used in Uzbekistan and their pharmacological properties. The present report can be useful for the continuous investigation of the Uzbek with the aim of obtaining new biologically active compounds.

Understanding the interactions between endophytic bacteria, rhizobia, free living root associated bacteria and their host plants under stressed conditions remains a significant challenge for proposing strategies to improve the efficacy of PGPR. In this study we analyzed the role of the endophytic bacterium Stenotrophomonas rhizophila in alleviating salinity stress in plants. The nodulation efficiency, plant growth, nitrogen and phosphorus uptake of soybean under hydroponic salt stress conditions were determined. Soybean seedlings were inoculated with Bradyrhizobium japonicum BDYD1 and S. rhizophila ep-17 were grown in hydroponic plastic pots containing 2 l of Hoagland solution for 42 days. Salinity conditions were established by adding 50 and 75 mM NaCl to the nutrient solution. The results showed that the salinity decreased the colonization of B. japonicum BDYD1 in the rhizosphere of soybean, inhibited shoot, root growth, and nodulation compared with those of unstressed plants. We found synergistic interactions between compatible salt tolerant S. rhizophila ep-17 and B. japonicum BDYD1 strains which were manifested themselves as improved root, shoot length, dry weight, N and P uptake and number of nodules compared with the uninoculated plants grown under 75 mM NaCl condition. S. rhizophila and Bradyrhizobium build beneficial association in the rhizosphere and can act synergistically on promoting plant growth, nutrient uptake and fitness of hydroponically grown soybean under salt stress condition.

It is a well accepted strategy to improve plant salt tolerance through inoculation with beneficial microorganisms. However, its underlying mechanisms still remain unclear. In the present study, hydroponic experiments were conducted to evaluate the effects of Bradyrhizobium japonicum USDA 110 with salt-tolerant Pseudomonas putida TSAU1 on growth, protein content, nitrogen, and phosphorus uptake as well as root system architecture of soybean (Glycine max L.) under salt stress. The results indicated that the combined inoculation with USDA 110 and TSAU1 significantly improved plant growth, nitrogen and phosphorus contents, and contents of soluble leaf proteins under salt stress compared to the inoculation with the symbiont alone or compared to un-inoculated ones. The root architectural traits, like root length, surface area, project area, and root volume; as well as nodulation traits were also significantly increased by co-inoculation with USDA 110 and TSAU1. The plant-growth promoting rhizobacteria (PGPR) P. putida strain TSAU1 could improve the symbiotic interaction between the salt-stressed soybean and B. japonicum USDA 110. In conclusion, inoculation with B. japonicum and salt-tolerant P. putida synergistically improved soybean salt tolerance through altering root system architecture facilitating nitrogen and phosphorus acquisition, and nodule formation.

This study examined the effects of phytohormone-producing Pseudomonas extremorientalis TSAU6 and plant growth regulators indole-3-acetic acid (IAA) and gibberellic acid (GA) on the growth parameters of jew’s mallow (Corchorus olitorius L.) under salt stress conditions. The inoculated jew’s mallow seeds with IAA- and GA-producing P. extremorientalis TSAU6 strain significantly increased root length by 45 %, shoot length by 84 %, and fresh weight by 28 % at 100 mM NaCl compared to uninoculated control plants. All concentrations of IAA and GA showed stimulatory effect on the root and shoot growth of jew’s mallow seedling under nonsaline and salt stress conditions. Plant growth-promoting properties of the strain in pot experiments with saline soil showed that P. extremorientalis TSAU 6 significantly increased shoot length by 21 % and dry matter of jew’s mallow by 18 %. Based on the results, it may be concluded that the integrative use of phytohormone-producing plant growth-promoting P. extremorientalis strain could be an eco-friendly strategy for increasing plant growth and development of jew’s mallow under saline soil condition. It is also indicated that plant growth regulators such as auxins and gibberellins play an important role in plant salinity tolerance.

Numerous studies have shown that soil salinity decreases nodulation and dramatically reduces N2 fixation and nitrogenase activity of nodulated legumes. Thus, the development of salt-tolerant symbioses is an absolute necessity to enable cultivation of leguminous crops in salt-affected soils. Dual inoculation of legumes with plant growth-promoting rhizobacteria (PGPR) and rhizobia has been reported to increase the number of nodules compared to those formed by a rhizobial strain alone. The production of IAA by Pseudomonas strains represents a beneficial mechanism that promoted enlargement of root system and thereby further enhanced nutrient uptake, nodulation, and shoot growth of leguminous plants. When PGPR are able to alleviate salt stress experienced by the plant, more nodules might develop into nitrogen-fixing ones, thereby enabling the plant to obtain part of its nitrogen from the atmosphere. Co-inoculation techniques could be a new approach to increase the salt tolerance and yield of legumes used for the food and green manure production in salt-affected soils, providing supply of biologically fixed N at low cost.

High salinity of soils in arid and semi arid regions results in desertification and decreased crop yield.In such conditions plants become more vulnerable to diseases caused by pathogenic fungi. The aim of the presentwork was to select enhanced root colonizing bacteria for their ability to promote plant growth and control root rotof cotton caused by Fusarium oxysporum in salinated soil. The best five enhanced cotton root tip colonizer bacteriawere selected from the rhizosphere of cotton grown in saline soil and were identified by the 16S rRNA gene sequenceas Pseudomonas spp., Pseudomonas putida, P. chlororaphis, Pseudomonas mendocina and Pantoea agglomerans.They showed ability to promote plant growth and to control root rot of cotton caused by F. oxysporum. Infestationof the soil with F. oxysporum resulted in an increase of diseased plants up to 60%. Selected bacterial strains,reduced this proportion to as low as 19 % and also stimulated cotton growth. These results are promising forthe application of selected environmentally safe biological control agents in protecting cotton against root rot diseasein saline agricultural soils., Kurak ve yarı kurak bölgelerde bulunan yüksek oranda tuz içeriğine sahip topraklar çoraklaşmaya yol açmakta ve böylece ürün veriminin azalmasına neden olmaktadır. Bu şartlar altında bitkiler patojenik mantarların neden olduğu hastalıklara karşı daha duyarlıdırlar. Bu araştırmanın amacı, bitkinin gelişme yeteneğini artıran kök koloni bakterisini seçmek ve tuzlu topraklardaki Fusarium oxysporum’un sebep olduğu pamuk kök çürüklüğü hastalığını kontrol altına almaktır. Araştırmada, gelişmiş pamuk kök kolonizer bakterisi tuzlu topraklarda büyüyen pamuk bitkisinin rizosferinden seçilmiş ve Pseudomonas spp., Pseudomonas putida, P. chlororaphis, Pseudomonas mendocina and Pantoea agglomerans gibi 16rRNA geni ile tanımlanmıştır. Araştırmada bitki büyüme süreci iyileştirilmiş ve F. Oxysporum ‘un sebep olduğu pamuk kök çürüklüğü kontrol altına alınmıştır. F. Oxysporum’un bulaşmış olduğu topraklarda hastalık oranı % 60 oranında artmıştır. Seçilen bakteri suşları bu oranı % 19 oranında azaltmış ve aynı zamanda pamuğun gelişmesini artırmıştır. Bu sonuçlar tuzlu tarım topraklarında yetiştirilen pamuk bitkisinde görülen kök çürüklüğü hastalığına karşı biyolojik kontrol etmenlerinin uygulanmasının yararlı olacağını göstermektedir

Abiotic stresses cause changes in the balance of phytohormones in plants and result in inhibited root growth and an increase in the susceptibility of plants to root rot disease. The aim of this work was to ascertain whether microbial indole-3-acetic acid (IAA) plays a role in the regulation of root growth and microbially mediated control of root rot of cotton caused by Fusarium solani. Seed germination and seedling growth were improved by both NaCl and Mg2SO4 (100mM) solutions when treated with root-associated bacterial strains Pseudomonas putida R4 and Pseudomonas chlororaphis R5, which are able to produce IAA. These bacterial strains were also able to reduce the infection rate of cotton root rot (from 70 to 39%) caused by F. solani under gnotobiotic conditions. The application of a low concentration of IAA (0.01 and 0.001μg/ml) stimulated plant growth and reduced disease incidence caused by F. solani (from 70 to 41–56%, respectively). Shoot and root growth and dry matter increased significantly and disease incidence was reduced by bacterial inoculants in natural saline soil. These results suggest that bacterial IAA plays a major role in salt stress tolerance and may be involved in induced resistance against root rot disease of cotton.