Plant growth-promoting rhizobacteria (PGPRs) represent a promising strategy for enhancing plant resilience and yields under drought-stress conditions. This study isolated and characterized PGPR from wheat rhizosphere soil in Egypt. Four PGPR strains were evaluated for an array of plant growth-promoting traits, including IAA production, biofilm formation, siderophore production, nitrogen fixation, ACC deaminase activity, phosphate solubilization, and antagonistic potential. Molecular identification via 16S rRNA sequencing classified three isolates (MMH101, MMH102, and MMH103) within the Bacillus genus and one isolate (MMH104) as Myroides sp. Greenhouse experiments examined the effects of PGPR inoculation on the drought-stressed Egyptian wheat cultivar, Gimmeza-9. Wheat plants inoculated with PGPR isolates showed dramatic improvements in growth parameters and stress tolerance indicators compared to non-inoculated controls when subjected to a 10-day drought period, with Bacillus rugosus (MMH101) inoculation resulting in increases of 61.8% in fresh biomass, 77.2% in dry biomass, 108.5% shoot length, and 134.9% root length. PGPR treatments also elevated the chlorophyll and proline content while reducing malondialdehyde levels. The findings demonstrate the effectiveness of PGPR inoculation in enhancing the morphology, physiology, and drought stress resilience of wheat. Isolated PGPR strains hold promise as biofertilizers for improving cereal productivity under water-deficit conditions.

Plants are severely affected by many biotic stresses, which cause a reduction in crop quality and quantity. One of the strategies to manage biotic stresses is the generation of transgenic plant lines that can be used as biosensors. These biose...

Background The potato tuber starch trait is affected by the composition of amylose and amylopectin. The synthesis of amylose in amyloplasts is catalyzed by granule-bound starch synthase (GBSS). GBSS gene expression was inhibited via CRISPR-Cas9-mediated genome editing in leaves of the Desiree Potato cultivar. Constructs containing the Cas9 gene and sgRNAs targeting the GBSS gene were introduced by Agrobacterium-mediated transformation delivery into protoplasts. Methods and results Outcomes included lines with mutations in all or only some of the homoeoalleles of GBSS genes and lines in which homoeoalleles carried different mutations and multiple alleles that were up to 21 % of regenerated shoots. Mutations were found in one bp from the used guide sequence, verifying the high homology between a guide sequence and a target region near the protospacer adjacent motif (PAM) site. DNA delivery into protoplast resulted in mutants with no detectable Cas9 gene. Microscopic evaluation of iodine-stained starch granules was shown to be a sensitive system for qualitative and quantitative examination of amylose formation in starch granules of transgenic potato tubers. Conclusion This study presented the successful application of CRISPRCas9 to fully knockout a GBSS gene function in a potato tetraploid plant in one round of transfection, without a stable introduction of DNA into the genome. In this study, the region of the GBSS gene was targeted, for driving the guide sequences. all the different experiments yielded high mutation frequencies, in the same order of magnitude, demonstrating the robustness of the CRISPR-Cas9 technique for potato research and breeding. Here, also the use of this new technology was demonstrated to develop a trait of commercial interest, an amylopectin potato starch, with uses in both food and technical applications.