Free-living bacteria that actively colonize plant roots and provide positive effects on plant development are called plant-growth promoting. Plant growth-promoting bacteria can promote plant growth and use their own metabolism to solubilize phosphates, produce hormones and fix nitrogen, and they can directly affect plant metabolism. PGPR also increase plant absorption of water and nutrients, improving root development and increasing plant enzymatic activity; moreover, PGPR can promote other microorganisms as part of a synergistic effect to improve their effects on plants, promoting plant growth or suppressing pathogens. Many studies have shown several benefits of the use of PGPR in maize and sugarcane crops. These bacteria are an excellent alternative to farmers to reduce chemical fertilization and pesticide input without promoting the environment impact and yield-reducing. The present review is an effort to elucidate the concept of rhizobacteria in the current scenario and their underlying mechanisms of plant growth promotion with recent updates. The latest paradigms of a wide range of applications of these beneficial rhizobacteria in both crops maize and sugarcane have been presented explicitly to garner broad perspectives regarding their functioning and applicability. The results from several studies have shown that the utilization of PGPR in maize and sugarcane is the great alternative to farmers face the challenge the modern agriculture.

Aim To investigate the plasma concentrations of glucose, insulin and tumour necrosis factor‐α (TNF‐α) of rats with maternal apical periodontitis (AP) and to explore the effect of maternal inflammation on the initial steps of insulin signalling and the inflammatory pathway in the gastrocnemius muscle (GM) and periepididymal white adipose tissue (pWAT) of adult offspring. Methodology Fifteen female Wistar rats were distributed into a control group (CN), a group with 1 tooth with AP (1AP) and a group with 4 teeth with AP (4AP). Thirty days following induction of AP, female rats from all groups were mated with healthy male rats. When male offspring reached 75 days of age, plasma concentrations of glucose, insulin and TNF‐α were quantified. Insulin resistance was evaluated by the homoeostasis model assessment of insulin resistance (HOMA‐IR) index. Phosphorylation status of pp185 tyrosine, insulin receptor substrate 1 (IRS‐1) serine, IκB kinase α/β (IKKα/β) and c‐Jun N‐terminal kinase (JNK) in the GM and pWAT were measured by Western blot. Analysis of variance was performed, followed by the Tukey's post hoc test. P values <0.05 were considered to be statistically significant. Results Maternal AP promoted insulin resistance, impaired the initial steps of insulin signalling, significantly increased plasma concentrations of insulin (P < 0.001) and TNF‐α (P < 0.05), and enhanced IKKα/β phosphorylation in the GM and pWAT (P < 0.05) of adult offspring. However, maternal AP did not affect fasting glycaemia and JNK phosphorylation in the GM and pWAT of adult offspring. Conclusions Maternal AP was associated with insulin resistance in adult offspring through alterations in insulin signalling and inflammation pathways. The study provides information on the impact of maternal AP on the development of metabolic alterations such as insulin resistance in adult offspring and reinforces the importance of preventing maternal AP in order to maintain the general health of offspring.

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Background Maternal periodontal disease leads to low birth weight (LBW), insulin resistance (IR), increased TNF‐α levels, and alterations in insulin signaling in adult offspring. TNF‐α has been associated with the stimulation of IKKβ/NF‐κB, resulting in the decreased expression of GLUT4. Another mechanism that may be involved in decreasing GLUT4 expression is DNA methylation. This study aimed to evaluate in the adult offspring of rats with periodontal disease: IR, inflammatory pathways, DNA methylation, and expression of GLUT4. Methods Female Wistar rats were distributed into control and experimental periodontal disease groups. Seven days after induction of periodontal disease, both groups were mated with healthy male rats. After weaning, male offspring were distributed into control offspring (CN‐o) and periodontal disease offspring (PED‐o) groups. Body weights were measured from 0–75 days of age. At day 75, the following were measured in the offspring: IR (HOMA‐IR index); TNF‐α and NF‐κBp65 content in the gastrocnemius muscle (GM) by western blotting; IKKα/β, JNK, ERK 1/2, NF‐κBp65, and NF‐κBp50 phosphorylation status in the GM by western blotting; DNA methylation by restriction digest and real‐time PCR(qAMP); and expression of GLUT4 mRNA in the GM by real‐time PCR. Results LBW, IR, increases in TNF‐α, IKKα/β, ERK 1/2, NF‐κBp65, and NF‐κBp50 decreased expression of GLUT4 mRNA were observed in the PED‐o rats. No differences were identified in JNK phosphorylation status and DNA methylation in the evaluated regions of the GLUT4‐encoding gene Slc2a4. Conclusion Maternal periodontal disease causes LBW, IR, activation of inflammatory pathways, and decreased GLUT4 expression in the GM of adult offspring.

The effect of Bacillus subtilis isolates before being used as inoculants is very important. They present various impacts on promotion and characteristics of plant at different stages of growth. This experiment was carried out on maize under greenhouse conditions with eleven treatments of endophytic bacteria and three repetitions. The better isolates under greenhouse conditions were used in the field experiment with four best treatments and six replicates. The traits evaluated under both conditions were height, shoot and root dry matter, and the nitrogen and phosphorus content in the plant and soil and the total number of bacteria in the soil. Under greenhouse conditions, the groups that received Bacillus spp. showed higher amount of soluble phosphorus and total numbers of bacteria compared to control. Under field condition, isolate BS-290 increased the nitrogen and phosphorus concentrations in shoot dry matter, phosphorus concentration in dry soil and the total number of bacteria in the soil, compared to the control. Isolate BS-320 increased the phosphorus concentration in plants and maize yield, which strongly suggests its use as a biological inoculant for maize crops. BS-248, BS 290 and BS-320 isolates promoted the highest maize growth, compared to the other isolates. The results showed that Bacillus subtilis isolates that promote plant growth did not increase similar traits in all plants and the behavior has been highly isolate-dependent. This finding shows that the isolates had a preference and certain specificity on each individual trait.