Differential elements of a successful agricultural innovation scaling-up model

Worldwide, there is currently an increasing demand for an active connection between the generation of innovations and the achievement of their escalation. Between 2015 and 2018 the scaling up of three varieties of yellow potatoes was carried out in Colombia within the framework of the "More Nutritious Potatoes" project, which had results beyond the objectives and goals proposed in a period of 28 months. One of the results of the project was the design of a Scaling-up model of innovations that linked agriculture with nutrition. This article answers the question: Which were the elements of the scaling-up model that allowed the results obtained in the More Nutritious Potatoes Project? To respond, a set of reference criteria was constructed from the literature. These criteria were contrasted with the theoretical project scaling-up model and its subsequent implementation in the field, using focus groups as a methodology and the model design analysis and its execution by the leaders and the evaluator of the project. The project's Scaling-up Model (SM) was found to include all benchmarks, in addition to identify three key elements that made the results possible: (i) the characteristics of the innovation, (ii) the trans-disciplinary work and (iii) facilitating elements of the process. The results of this exercise complement the evaluated scaling-up model and become benchmarks in the design of innovation scaling-up processes.

Uncovering anthocyanin diversity in potato landraces (Solanum tuberosum L. Phureja) using RNA-seq

Potato (Solanum tuberosum L.) is the third largest source of antioxidants in the human diet, after maize and tomato. Potato landraces have particularly diverse contents of antioxidant compounds such as anthocyanins. We used this diversity to study the evolutionary and genetic basis of anthocyanin pigmentation. Specifically, we analyzed the transcriptomes and anthocyanin content of tubers from 37 landraces with different colorations. We conducted analyses of differential expression between potatoes with different colorations and used weighted correlation network analysis to identify genes whose expression is correlated to anthocyanin content across landraces. A very significant fraction of the genes identified in these two analyses had annotations related to the flavonoid-anthocyanin biosynthetic pathway, including 18 enzymes and 5 transcription factors. Importantly, the causal genes at the D, P and R loci governing anthocyanin accumulation in potato cultivars also showed correlations to anthocyanin production in the landraces studied here. Furthermore, we found that 60% of the genes identified in our study were located within anthocyanin QTLs. Finally, we identified new candidate enzymes and transcription factors that could have driven the diversification of anthocyanins. Our results indicate that many anthocyanins biosynthetic genes were manipulated in ancestral potato breeding and can be used in future breeding programs.

Pathway-based analysis of anthocyanin diversity in diploid potato

Anthocyanin biosynthesis is one of the most studied pathways in plants due to the important ecological role played by these compounds and the potential health benefits of anthocyanin consumption. Given the interest in identifying new genetic factors underlying anthocyanin content we studied a diverse collection of diploid potatoes by combining a genome-wide association study and pathway-based analyses. By using an expanded SNP dataset, we identified candidate genes that had not been associated with anthocyanin variation in potatoes, namely a Myb transcription factor, a Leucoanthocyanidin dioxygenase gene and a vacuolar membrane protein. Importantly, a genomic region in chromosome 10 harbored the SNPs with strongest associations with anthocyanin content in GWAS. Some of these SNPs were associated with multiple anthocyanin compounds and therefore could underline the existence of pleiotropic genes or anthocyanin biosynthetic clusters. We identified multiple anthocyanin homologs in this genomic region, including four transcription factors and five enzymes that could be governing anthocyanin variation. For instance, a SNP linked to the phenylalanine ammonia-lyase gene, encoding the first enzyme in the phenylpropanoid biosynthetic pathway, was associated with all of the five anthocyanins measured. Finally, we combined a pathway analysis and GWAS of other agronomic traits to identify pathways related to anthocyanin biosynthesis in potatoes. We found that methionine metabolism and the production of sugars and hydroxycinnamic acids are genetically correlated to anthocyanin biosynthesis. The results contribute to the understanding of anthocyanins regulation in potatoes and can be used in future breeding programs focused on nutraceutical food.

Vitamin C, protein, and dietary fibre contents as affected by genotype, agro-climatic conditions, and cooking method on tubers of Solanum tuberosum Group Phureja

The simultaneous effect of genotype, agro-climatic conditions, and cooking method was evaluated towards the contents of vitamin C, protein, and soluble, insoluble, and total dietary fibre in potato tubers from the Group Phureja. Within the tested treatments, vitamin C was affected the most (9.4-85.1 mg/100 g DW), followed by insoluble dietary fibre (3.9-16.6 g/100 DW), soluble dietary fibre (1.0-3.9 g/100 g DW), total dietary fibre (3.6-fold change), and protein (1.7-4.3 g/100 g DW). The cooking method had a high effect on the variability of the contents of vitamin C, protein, insoluble dietary fibre, and total dietary fibre (74.2-92.8% of the total variance). In contrast, not only the cooking method, but also the agro-climatic conditions had a high effect on the content of soluble dietary fibre (32.6 and 34.8% of the total variance, respectively). Total dietary fibre had a protective effect on vitamin C upon cooking.

Novel SNP markers in InvGE and SssI genes are associated with natural variation of sugar contents and frying color in Solanum tuberosum Group Phureja

Background

Potato frying color is an agronomic trait influenced by the sugar content of tubers. The candidate gene approach was employed to elucidate the molecular basis of this trait in Solanum tuberosum Group Phureja, which is mainly diploid and represents an important genetic resource for potato breeding. The objective of this research was to identify novel genetic variants related with frying quality in loci with key functions in carbohydrate metabolism, with the purpose of discovering genetic variability useful in breeding programs. Therefore, an association analysis was implemented with 109 SNP markers identified in ten candidate genes.

Results

The analyses revealed four associations in the locus InvGE coding for an apoplastic invertase and one association in the locus SssI coding for a soluble starch synthase. The SNPs SssI-C_45711901T and InvGE-C_2475454T were associated with sucrose content and frying color, respectively, and were not found previously in tetraploid genotypes. The rare haplotype InvGE-A_2475187C_2475295A_2475344 was associated with higher fructose contents. Our study allowed a more detailed analysis of the sequence variation of exon 3 from InvGE, which was not possible in previous studies because of the high frequency of insertion-deletion polymorphisms in tetraploid potatoes.

Conclusion

The association mapping strategy using a candidate gene approach in Group Phureja allowed the identification of novel SNP markers in InvGE and SssI associated with frying color and the tuber sugar content measured by High Performance Liquid Chromatography (HPLC). These novel associations might be useful in potato breeding programs for improving quality traits and to increase crop genetic variability. The results suggest that some genes involved in the natural variation of tuber sugar content and frying color are conserved in both Phureja and tetraploid germplasm. Nevertheless, the associated variants in both types of germplasm were present in different regions of these genes. This study contributes to the understanding of the genetic architecture of tuber sugar contents and frying color at harvest in Group Phureja.

Electronic supplementary material

The online version of this article (doi:10.1186/s12863-017-0489-3) contains supplementary material, which is available to authorized users.