Suppressing photorespiration for the improvement in photosynthesis and crop yields: A review on the role of S-allantoin as a nitrogen source.

Environmental variations resulting in biotic and abiotic stresses demand adaptive changes in the photosynthetic machinery. To cope with these challenges, plant scientists are constantly striving to enhance photosynthetic activity. The photorespiration pathway, which fixes O2 and releases CO2 in C3 plants, competes with photosynthesis. One method to increase yield would be to enhance photosynthesis by engineering the photorespiratory pathway. To date, three engineered photorespiratory pathways have been produced, of which two have been proven experimentally in the model plant, Arabidopsis thaliana. These approaches might be helpful in enhancing crop resilience to future environmental challenges. In partially photorespiratory suppressed plants, it is hypothesized that a gene cluster may have formed between bacterial glycolate dehydrogenase (GDH), glyoxylate carboligase (GCL), and tartronic semi aldehyde (TSR) genes with Arabidopsis allantoin degradation genes like Arabidopsis allantoinase (AtALN) to utilize S-allantoin as a source of nitrogen. Observations of the use of allantoin as an exclusive source of nitrogen or energy by Arabidopsis and Escherichia coli led us to propose a genetic switch control model between nitrogen assimilation and energy producing pathways in partially photorespiratory suppressed plants.

Current status and future possibilities of molecular genetics techniques in Brassica napus.

As PCR methods have improved over the last 15 years, there has been an upsurge in the number of new DNA marker tools, which has allowed the generation of high-density molecular maps for all the key Brassica crop types. Biotechnology and molecular plant breeding have emerged as a significant tool for molecular understanding that led to a significant crop improvement in the Brassica napus species. Brassica napus possess a very complicated polyploidy-based genomics. The quantitative trait locus (QTL) is not sufficient to develop effective markers for trait introgression. In the coming years, the molecular marker techniques will be more effective to determine the whole genome impairing desired traits. Available genetic markers using the single-nucleotide sequence (SNP) technique and high-throughput sequencing are effective in determining the maps and genome polymorphisms amongst candidate genes and allele interactions. High-throughput sequencing and gene mapping techniques are involved in discovering new alleles and gene pairs, serving as a bridge between the gene map and genome evaluation. The decreasing cost for DNA sequencing will help in discovering full genome sequences with less resources and time. This review describes (1) the current use of integrated approaches, such as molecular marker technologies, to determine genome arrangements and interspecific outcomes combined with cost-effective genomes to increase the efficiency in prognostic breeding efforts. (2) It also focused on functional genomics, proteomics and field-based breeding practices to achieve insight into the genetics underlying both simple and complex traits in canola.