The com armyworm (Spodoptera exigua Hub. Zimm.) is one of the most important pests of corn crop in Khuzestan province of Iran. Young corn plants are more susceptible to this insect defoliator. Microbial control of S. exigua specially by Bacillus thuringiensis Ber. is one of the most effective methods and is recommended by workers. This research was conducted to evaluate B. thuringiensis pathogenicity both in laboratory and field trials, in Khuzestan province. In prime step, different serotypes were evaluated by bioassay in the laboratory conditions. The results demonstrated that serotypes 1 and 3a3b were more virulent compare to third strain. In other bioassay, it was shown that second larval instars was more susceptible and along with larval growth and development, virulence of spores and crystal bodies lowered, significantly. Also, it was shown that in a few hours, affected larvae restrained significantly to feeding from corn leaves, compared with control. Application of surfactant agents such as triton x-100 in BACTERIAl suspension increased virulence of the pathogen on associated host. In the field studies, virulence of B. thuringiensis was the same as the laboratory studies. Based on our results, B. thuringiensis can be accounted as an effective biological control agent for S. exigua in Khuzestan province.

Phosphorus (P) is one of the most vital elements for all living organisms which acts as a constituent of essential biomolecules such as nucleic acids, phospholipids, and phosphosugars, and as a major contributor to almost all metabolic reactions including photosynthesis, respiration, and energy delivery. It is one of the most needed nutrients for plant growth and development. Despite high levels of P in the soil, plants absorb it only in the soluble inorganic form of free phosphate ion (Pi) which is scarce in soil. Therefore, there has been a large demand for Pi fertilizers to secure crop yields, yet its deposition in soil and gradual run-off into water reservoirs lead to chains of events that cause irreversible damages to ecosystems. Researches, including genome-wide data analyses, have revealed interesting molecular aspects of plant adaptive strategies to deal with low Pi concentrations in soil. These include the higher expression of acid phosphatases and Pi transporters as well as the secretion of organic acids in the rhizosphere that maintain cellular Pi homeostasis in order to keep metabolic reactions running. Describing the cycle of Pi exchange between physical and biological worlds, the extent to which current agricultural practices are disturbing the cycle, the necessity of introducing lessdestructive methods of providing Pi, and alternative measures and solutions for sustainable agriculture will be discussed in this review.

To study the seprate and combined effects of phosphorus fertilizer, Phosphatesolubilizing BACTERIA and mycorrhizal fungus on reducing drought stress damages of grain corn (SC704) during its vegetative stages under field conditions, an experiment was conducted as split plot based on RCBD with three replications at College of Abouraihan, University of Tehran in 2009. Experimental factors were drought stress as main-plot (irrigation after 50 as control, 100 and 150 mm evaporation from pan class A) and fertilizer plus biofertilizer compounds as sub-plots. Drought stress began after seedling stage. Analysis of variance showed that drought stress significantly affected most of investigated traits such as number of row/ ear, number of kernel/ row, ear weight, 1000kernel weight and grain yield. All the measured traits in compounds PHOSPHATE-SOLUBILIZING BACTERIA, mycorrhiza fungies and triple super phosphate treatment were higher than other treatments under water deficit stress conditions.Frthermore, grain yield in triple super phosphate treat under severe water deficit stress conditions (1.81 ton/ha) were significantly less than normal irrigation (8.38 ton/ha) and low stress conditions (4.98 ton/ha). According to this experiment, seed inoculation with PHOSPHATE-SOLUBILIZING BACTERIA, mycorrhiza fungies and triple super phosphate compounds affected grain yield and harvest index significantly. This experiment showed that PHOSPHATE-SOLUBILIZING microorganisms can positively interact in promoting plant growth as well as in P uptake in maize plant, leading to improve plant tolerance under water deficit stress conditions.

Probiotics have been used for over a century to prevent and treat diseases. They can reduce the effects of gastroenteritis and are now used to treat acute diarrhea. This study aimed to evaluate the co-aggregative effects of probiotics BACTERIA against diarrheal causative BACTERIA. For this purpose, 11 isolates of probiotic BACTERIA were used in the current study, including three Lactobacillus plantarum, one Lactobacillus gasseri, two Lactobacillus fermentum, three Lactobacillus acidophilus, and two Lactococcus garvieae isolates. All isolates were tested for antibiotic susceptibility, autoaggregation ability, adhesion ability, antiBACTERIAl activity, acid tolerance, and bile salts tolerance. The results showed that most of them had the ability to autoaggregate after 4 h, with the highest percentage of 57.14% for L. fermentum. For the antibiotic susceptibility test, all the isolates showed resistance against trimethoprim/sulfamethoxazole, except one isolate. Moreover, all the isolates, except one, were susceptible to both vancomycin and tetracycline. All tested isolates had adhesion ability with different survival rates, which reached 34.57% for L. plantarum in acidic conditions. Besides, the highest survival rate was 85.17%, which belonged to L. garvieae, for bile salt tolerance. Probiotic isolates had an antiBACTERIAl effect against diarrhea-causative BACTERIA with an inhibition diameter of 17-49 mm for different Lactobacillus spp. and Lactococcus spp. isolates. Furthermore, the co-aggregation ability of probiotic isolates against diarrhea-causative BACTERIA was studied, and results showed that probiotic isolates had a co-aggregative effect against diarrhea-causative BACTERIA, Escherichia coli, Shigella sonnei, and Providencia alcalifaciens, after 24 h of incubation. The highest co-aggregative effect of probiotics isolates belonged to L. fermentum and L. acidophilus against P. alcalifaciens with a co-aggregation percentage of 100%, while the lowest co-aggregation rate was 14.29% against E. coli.  The findings revealed the probiotic properties and co-aggregative effects of probiotic BACTERIA against diarrhea-causative BACTERIA.