Effect of combined use of fertilizer and plant growth stimulating bacteria Rhizobium, Azospirillum, Azotobacter and Pseudomonas on the quality and components of corn forage in Iran

Enhance of tomato production and induction of changes on the organic profile mediated by Rhizobium biofortification

Introduction

The extensive use of chemical fertilizers has served as a response to the increasing need for crop production in recent decades. While it addresses the demand for food, it has resulted in a decline in crop productivity and a heightened negative environmental impact. In contrast, plant probiotic bacteria (PPB) offer a promising alternative to mitigate the negative consequences of chemical fertilizers. PPB can enhance nutrient availability, promote plant growth, and improve nutrient uptake efficiency, thereby reducing the reliance on chemical fertilizers.

Methods

This study aimed to evaluate the impact of native Rhizobium strains, specifically Rhizobium calliandrae LBP2-1, Rhizobium mayense NSJP1-1, and Rhizobium jaguaris SJP1- 2, on the growth, quality, and rhizobacterial community of tomato crops. Various mechanisms promoting plant growth were investigated, including phosphate solubilization, siderophore production, indole acetic acid synthesis, and cellulose and cellulase production. Additionally, the study involved the assessment of biofilm formation and root colonization by GFP-tagged strains, conducted a microcosm experiment, and analyzed the microbial community using metagenomics of rhizospheric soil.

Results

The results showed that the rhizobial strains LBP2-1, NSJP1-1 and SJP1-2 had the ability to solubilize dicalcium phosphate, produce siderophores, synthesize indole acetic acid, cellulose production, biofilm production, and root colonization. Inoculation of tomato plants with native Rhizobium strains influenced growth, fruit quality, and plant microbiome composition. Metagenomic analysis showed increased Proteobacteria abundance and altered alpha diversity indices, indicating changes in rhizospheric bacterial community.

Discussion

Our findings demonstrate the potential that native Rhizobium strains have to be used as a plant probiotic in agricultural crops for the generation of safe food and high nutritional value.

Specific Identification Method based on PCR for Drosophila melanogaster

D. melanogaster is one of the most harmful citrus fruit flies having a large number of host plants. The molecular diagnostic method has been created for identification the D. melanogaster from another non-quarantine species Drosophila spp. The proposed method for differentiation is to use the mitochondrial DNA cytochrome oxidase I gene region 709-bp. We amplified samples of DNA with primers Droso-S391 and Droso-A381 by D. melanogaster, D. suzukii, and D. Simulans collections in the laboratory samples from many countries and contrasted with sequences of other GenBank Drosophila taxa. The findings of a polymerase chain reaction (PCR) based on DNA sequence polymorphisms showed that these primers accurately identify the area of the gene as well as the unique primers of Drosophila melanogaster.