Fertile transgenic plants obtained from tritordeum inflorescences by tissue electroporation

 Tissue electroporation was applied to a member of the Triticeae family, namely tritordeum (Hordeum chilense Roem.×Triticum turgidum L. Conv. durum), for the generation of fertile transgenic plants. Two transgenic plants were recovered following the treatment of 361 explants of immature inflorescences (although they were subsequently found to result from the same transformation event). The expression of both inserted marker genes (uidA and bar) was confirmed using standard assays, while transgene integration was confirmed using PCR and Southern hybridization analyses. Integration pattern, segregation ratio and the inheritance of transgene expression in T₁ progeny were consistent for the presence of a single transgene locus containing five to ten plasmid insertions. Although this procedure has been applied to other cereal species, stable transformation of the Triticeae using tissue electroporation has not previously been reported.

Genetic transformation of einkorn (Triticum monococcum L. ssp. monococcum L.), a diploid cultivated wheat species

BACKGROUND

Domesticated einkorn (Triticum monococcum L.) is one of the oldest cultivated cereal crops in the world. Its small genome size (~ 5.7 GB), low ploidy (2n = 2x = 14, AmAm) and high genetic polymorphism make this species very attractive for use as a diploid model for understanding the genomics and proteomics of Triticeae. Einkorn, however, is still a recalcitrant monocotyledonous species for the application of modern biotechnologies, including transgenesis. This paper reports the factors that may influence transgene delivery, integration, expression and inheritance in einkorn.

RESULTS

In this study, we report the successful genetic transformation of einkorn using biolistic-mediated DNA delivery. Immature embryo-derived tissues of spring einkorn were bombarded with a plasmid containing the reporter gene GFP (green fluorescent protein) driven by the rice actin promoter (act1) and the selectable bar gene (bialaphos resistance gene) driven by the maize ubiquitin promoter (ubi1). Adjustments to various parameters such as gas pressure, microcarrier size and developmental stage of target tissue were essential for successful transient and stable transformation. Bombarded einkorn tissues are recalcitrant to regenerating plants, but certain modifications of the culture medium have been shown to increase the production of transgenic events. In various experiments, independent transgenic plants were produced at frequencies ranging from 0.0 to 0.6%. Molecular analysis, marker gene expression and herbicide treatment demonstrated that gfp/bar genes were stably integrated into the einkorn genome and successfully inherited over several generations. The transgenes, as dominant loci, segregated in both Mendelian and non-Mendelian fashion due to multiple insertions. Fertile homozygous T1-T2 populations of transgenic einkorn that are resistant to herbicides were selected.

CONCLUSION

To the best of our knowledge, this is the first report of the production of genetically modified einkorn plants. We believe that the results of our research could be a starting point for the application of the current biotechnological-based technologies, such as transgenesis and genome editing, to accelerate comparative functional genomics in einkorn and other cereals.

A competence of embryo-derived tissues of tetraploid cultivated wheat species Triticum dicoccum and Triticum timopheevii for efficient and stable transgenesis mediated by particle inflow gun

BACKGROUND

The ability to engineer cereal crops by gene transfer technology is a powerful and informative tool for discovering and studying functions of genes controlling environmental adaptability and nutritional value. Tetraploid wheat species such as emmer wheat and Timopheevi wheat are the oldest cereal crops cultivated in various world areas long before the Christian era. Nowadays, these hulled wheat species are gaining new interest as donors for gene pools responsible for the improved grain yield and quality, tolerance for abiotic and biotic stress, resistance to pests and disease. The establishing of efficient gene transfer techniques for emmer and Timopheevi wheat may help in creation of modern polyploid wheat varieties.

RESULTS

In the present study, we describe a robust protocol for the production of fertile transgenic plants of cultivated emmer wheat (Russian cv. 'Runo') using a biolistic delivery of a plasmid encoding the gene of green fluorescent protein (GFP) and an herbicide resistance gene (BAR). Both the origin of target tissues (mature or immature embryos) and the type of morphogenic calli (white or translucent) influenced the efficiency of stable transgenic plant production in emmer wheat. The bombardment of nodular white compact calluses is a major factor allowed to achieve the highest transformation efficiency of emmer wheat (on average, 12.9%) confirmed by fluorescence, PCR, and Southern blot. In the absence of donor plants for isolation of immature embryos, mature embryo-derived calluses could be used as alternative tissues for recovering transgenic emmer plants with a frequency of 2.1%. The biolistic procedure based on the bombardment of immature embryo-derived calluses was also successful for the generation of transgenic Triticum timopheevii wheat plants (transformation efficiency of 0.5%). Most of the primary events transmitted the transgene expression to the sexual progeny.

CONCLUSION

The procedures described here can be further used to study the functional biology and contribute to the agronomic improvement of wheat. We also recommend involving in such research the Russian emmer wheat cv. 'Runo', which demonstrates a high capacity for biolistic-mediated transformation, exceeding the previously reported values for different genotypes of polyploid wheat.

Inheritance and effectiveness of two transgenes determining PVY resistance in progeny from crossing independently transformed tobacco lines

Genetic transformation of plants allows us to obtain improved genotypes enriched with the desired traits. However, if transgenic lines were to be used in breeding programs the stability of inserted transgenes is essential. In the present study, we followed the inheritance of transgenes in hybrids originated from crossing two transgenic tobacco lines resistant to Potato virus Y (PVY): MN 944 LMV with the transgene containing Lettuce mosaic virus coat protein gene (LMV CP) and AC Gayed ROKY2 with PVY replicase gene (ROKY2). Progeny populations generated by successive self-pollination were analyzed with respect to the transgene segregation ratio and resistance to Potato virus Y in tests carried out under greenhouse conditions. The presence of the virus in inoculated plants was detected by DAS-ELISA method. The results demonstrated the Mendelian fashion of inheritance of transgenes which were segregated independently and stably. As a result, we obtained T4 generation of hybrid with both transgenes stacked and which was highly resistant to PVY.

Increased artemisinin production in Artemisia annua L. by co-overexpression of six key biosynthetic enzymes

Malaria remains a global health issue, especially in resource-limited regions. Artemisinin, a key antimalarial compound from Artemisia annua, is crucial for treatment, but low natural yields hinder large-scale production. In this study, we employed advanced transgenic technology to co-overexpress six key biosynthetic enzymes-Isopentenyl Diphosphate Isomerase (IDI), Farnesyl Pyrophosphate Synthase (FPS), Amorpha 4,11-diene Synthase (ADS), cytochrome P450 monooxygenase (CYP71AV1), cytochrome P450 oxidoreductase (AACPR) and artemisinic aldehyde D11 reductase (DBR2)-in A. annua to significantly enhance artemisinin production. Our innovative approach utilized a co-expression strategy to optimize the artemisinin biosynthetic pathway, leading to a remarkable up to 200 % increase in artemisinin content in T1 transgenic plants compared to non-transgenic controls. The stability and efficacy of this transformation were confirmed in subsequent generations (T2), achieving a potential 232 % increase in artemisinin levels. Additionally, we optimized transgene expression to maintain plant growth and development, and performed untargeted metabolite analysis using GC-MS, which revealed significant changes in metabolite composition among T2 lines, indicating effective diversion of farnesyl diphosphate into the artemisinin pathway. This metabolic engineering breakthrough offers a promising and scalable solution for enhancing artemisinin production, representing a major advancement in the field of plant biotechnology and a potential strategy for more cost-effective malaria treatment.

Expression and inheritance of foreign genes in transgenic peanut plants generated byAgrobacterium-mediated transformation

To evaluate and characterize the stability of traits transferred viaAgrobacterium transformation, foreign gene expression must be examined in sexually derived progeny. The objective of this study was to analyze three transgenic peanut plants, 1-10, 12-1, and 17-1, for the inheritance and expression of their foreign genes. Segregation ratios for the introduced genes in T₂ plants gave either 100% or 3:1 expression of the β-glucuronidase (GUS) gene, demonstrating recovery of both homozygous and heterozygous T₁ plants. Fluorometric GUS assay in T₁ and T₂ generations of all three plants showed that the GUS gene was stably expressed in the progeny. DNA analyses showed 100% concordance between the presence of the foreign gene and enzyme activity. Our results demonstrate that transgenes in peanut introduced byAgrobacterium can be inherited in a Mendelian manner.