Transcriptome analysis reveals biosynthesis and regulation of flavonoid in common bean seeds during grain filling.

The Andean domesticated common beans (Phaseolus vulgaris) are significant sources of phenolic compounds associated with health benefits. However, the regulation of biosynthesis of these compounds during bean seed development remains unclear. To elucidate the gene expression patterns involved in the regulation of the flavonoid pathway, we conducted a transcriptome analysis of two contrasting Chilean varieties, Negro Argel (black bean) and Coscorron (white bean), at three developmental stages associated with seed color change, as well as different flavonoid compound accumulations. Our study reveals that phenolic compound synthesis initiates during seed filling, although it exhibits desynchronization between both varieties. We identified 10,153 Differentially Expressed Genes (DEGs) across all comparisons. The KEGG pathway 'Flavonoid biosynthesis' showed enrichment of induced DEGs in Negro Argel (PV172), consistent with the accumulation of delphinidin, petunidin, and malvidin hexosides in their seeds, while catechin glucoside, procyanidin and kaempferol derivatives were predominantly detected in Coscorrón (PV24). Furthermore, while the flavonoid pathway was active in both varieties, our results suggest that enzymes involved in the final steps, such as ANS and UGT, were crucial, inducing anthocyanin formation in Negro Argel. Additionally, during active anthocyanin biosynthesis, the accumulation of reserve proteins or those related to seed protection and germination was induced. These findings provide valuable insights and serve as a guide for plant breeding aimed at enhancing the health and nutritional properties of common beans.

A single-nucleotide polymorphism in PvPW1 encoding ß-1,3-glucanase 9 is associated with pod width in Phaseolus vulgaris L.

Pod width influences pod size, shape, yield, and consumer preference in snap beans (Phaseolus vulgaris L.). In this study, we map PvPW1, a quantitative trait locus associated with pod width in snap beans, through genotyping and phenotyping of recombinant plants. We identify Phvul.006G072800, encoding the ß-1,3-glucanase 9 protein, as the causal gene for PvPW1. The PvPW1G3555 allele is found to positively regulate pod width, as revealed by an association analysis between pod width phenotype and the PvPW1G3555C genotype across 17 bi-parental F2 populations. 97.7% of the 133 wide pod accessions carry PvPW1G3555, while 82.1% of the 78 narrow pod accessions carry PvPW1C3555, indicating strong selection pressure on PvPW1 during common bean breeding. Re-sequencing data from 59 common bean cultivars identify an 8-bp deletion in the intron linked to PvPW1C3555, leading to the development of the InDel marker of PvM436. Genotyping 317 common bean accessions with PvM436 demonstrated that accessions with PvM436247 and PvM436227 alleles have wider pods compared to those with PvM436219 allele, establishing PvM436 as a reliable marker for molecular breeding in snap beans. These findings highlight PvPW1 as a critical gene regulating pod width and underscore the utility of PvM436 in marker-assisted selection for snap bean breeding.

Investigating the influence of eco-friendly approaches on saline soil traits and growth of common bean plants (Phaseolus vulgaris L.).

Soil salinization significantly impacts agricultural lands and crop productivity in the study area. Moreover, freshwater scarcity poses a significant obstacle to soil reclamation and agricultural production. Therefore, eco-friendly strategies must be adopted for agro-ecosystem sustainability under these conditions. A study conducted in 2022 and 2023 examined the interaction effects of various soil mulching materials (unmulched, white plastic, rice straw, and sawdust) and chitosan foliar spray application (control, 250 mg L-1 of normal chitosan, 125 mg L-1 of nano chitosan, and 62.5 mg L-1 of nano chitosan) on the biochemical soil characteristics and productivity of common beans in clay-saline soil. Higher organic matter, available nutrient content, and total bacteria count in soils were found under organic mulching treatments (rice straw and sawdust). In contrast, the white plastic mulching treatment resulted in the lowest values of soil electrical conductivity (EC) and the highest soil water content. Conversely, chitosan foliar spray treatments had the least impact on the chemical properties of the soil. Plants sprayed with 62.5 mg L-1 of nano chitosan exhibited higher chlorophyll content, plant height, fresh weight of shoots and roots, seed yield, and nutrient content compared to other chitosan foliar spray applications. All treatments studied led to a significant reduction in fungal communities and Na% in plants. The combined effect of organic mulch materials and foliar spray application of 62.5 mg L-1 nano chitosan appeared to enhance biochemical saline soil properties and common bean productivity.

Research on variety identification of common bean seeds based on hyperspectral and deep learning.

Accurate, fast and non-destructive identification of varieties of common bean seeds is important for the cultivation and efficient utilization of common beans. This study is based on hyperspectral and deep learning to identify the varieties of common bean seeds non-destructively. In this study, the average spectrum of 3078 hyperspectral images from 500 varieties was obtained after image segmentation and sensitive region extraction, and the Synthetic Minority Over-sampling Technique (SMOTE) was used to achieve the equilibrium of the samples of various varieties. A one-dimensional convolutional neural network model (IResCNN) incorporating Inception module and residual structure was proposed to identify seed varieties, and Support Vector Machine (SVM), K-Nearest Neighbor (KNN), VGG19, AlexNet, ResNet50 were established to compare the identification effect. After analyzing the effects of multiple spectral preprocessing methods on the model, the study selected Savitzky-Golay smoothing correction (SG) for spectral preprocessing and extracted 66 characteristic wavelengths using Successive Projections Algorithm (SPA) as inputs to the discriminative model. Ultimately, the IResCNN model achieved the highest accuracy of 93.06 % on the test set, indicating that hyperspectral technology can accurately identify bean varieties, and the study provides a correct method of thinking for the non-destructive classification of multi-species small-sample bean varieties.

Private sector led multi-stakeholder platforms positively influence certified common bean seed supply in Malawi.

Common bean yields in Malawi remain low, primarily due to the use of low-yielding, recycled local seeds by most smallholder farmers. The low uptake of certified bean seed is attributed to limited incentives from the private sector. This study hypothesizes that the sustainable adoption of market-preferred varieties can be achieved by synchronizing and linking seed production to the grain market through committed value chain actors in a private sector-led multi-stakeholder platform. This paper examines the role of private sector-led multi-stakeholder platforms in the supply of certified common bean seed in Malawi. The research draws on both qualitative and quantitative primary data collected through a semi-structured questionnaire and interviews with key informants. Data were analyzed using an Ordinary Least Squares (OLS) regression model. The results indicate that several variables representing membership in multi-stakeholder platforms (MSPs) significantly affect the supply of certified common bean seed. Participation in MSPs, contractual arrangements, market structure, extension services, and seed demonstrations positively influenced seed supply. The findings underscore the need for a well-coordinated multi-stakeholder platform to enhance the supply of certified common bean seed, supported by effective policies and incentives from policymakers.

Cell size differences affect photosynthetic capacity in a Mesoamerican and an Andean genotype of Phaseolus vulgaris L.

The efficiency of CO2 flux in the leaf is hindered by a several structural and biochemical barriers which affect the overall net photosynthesis. However, the dearth of information about the genetic control of these features is limiting our ability for genetic manipulation. We performed a comparative analysis between three-week-old plants of a Mesoamerican and an Andean cultivar of Phaseolus vulgaris at variable light and CO2 levels. The Mesoamerican bean had higher photosynthetic rate, maximum rate of rubisco carboxylase activity and maximum rate of photosynthetic electron transport at light saturation conditions than its Andean counterpart. Leaf anatomy comparison between genotypes showed that the Mesoamerican bean had smaller cell sizes than the Andean bean. Smaller epidermal cells in the Mesoamerican bean resulted in higher stomata density and consequently higher stomatal conductance for water vapor and CO2 than in the Andean bean. Likewise, smaller palisade and spongy mesophyll cells in the Mesoamerican than in the Andean bean increased the cell surface area per unit of volume and consequently increased mesophyll conductance. Finally, smaller cells in the Mesoamerican also increased chlorophyll and protein content per unit of leaf area. In summary, we show that different cell sizes controls the overall net photosynthesis and could be used as a target for genetic manipulation to improve photosynthesis.

Genome-Wide Association for Morphological and Agronomic Traits in Phaseolus vulgaris L. Accessions.

Exploring genetic resources through genomic analyses has emerged as a powerful strategy to develop common bean (Phaseolus vulgaris L.) cultivars that are both productive and well-adapted to various environments. This study aimed to identify genomic regions linked to morpho-agronomic traits in Mesoamerican and Andean common bean accessions and to elucidate the proteins potentially involved in these traits. We evaluated 109 common bean accessions over three agricultural years, focusing on traits including the grain yield (YDSD), 100-seed weight (SW), number of seeds per pod (SDPD), number of pods per plant (PDPL), first pod insertion height (FPIH), plant height (PLHT), days to flowering (DF), and days to maturity (DPM). Using multilocus methods such as mrMLM, FASTmrMLM, FASTmrEMMA, ISIS EM-BLASSO, and pLARmEB, we identified 36 significant SNPs across all chromosomes (Pv01 to Pv11). Validating these SNPs and candidate genes in segregating populations is crucial for developing more productive common bean cultivars through marker-assisted selection.

Common Bean Suppresses Hepatic Ceramide Metabolism in a Mouse Model of Metabolic Dysfunction-Associated Steatotic Liver Disease.

Background/Objectives: The incidence of metabolic dysfunction-associated steatotic liver disease (MASLD), a condition linked to the ongoing obesity pandemic, is rapidly increasing worldwide. In turn, its multifactorial etiology is consistently associated with low dietary quality. Changing dietary macronutrient and phytochemical quality via incorporating cooked common bean into an obesogenic diet formulation has measurable health benefits on the occurrence of both obesity and hepatic steatosis in C57BL/6 mice. Methods: A cohort of C57BL/6 mice were randomized into experimental diets containing multiple dietary concentrations of common bean. The primary endpoint of this study was comparing metabolomic analyses from liver and plasma of different treatment groups. Additionally, RNA sequencing and protein expression analysis via nanocapillary immunoelectrophoresis were used to elucidate signaling mediators involved. Results: Herein, global metabolomic profiling of liver and plasma identified sphingolipids as a lipid subcategory on which bean consumption exerted significant effects. Of note, C16 and C18 ceramides were significantly decreased in bean-fed animals. Hepatic RNAseq data revealed patterns of transcript expression of genes involved in sphingolipid metabolism that were consistent with metabolite profiles. Conclusions: Bean incorporation into an otherwise obesogenic diet induces effects on synthesis, biotransformation, and degradation of sphingolipids that inhibit the accumulation of ceramide species that exert pathological activity. These effects are consistent with a mechanistic role for altered sphingolipid metabolism in explaining how bean inhibits the development of MASLD.

Effect of post-harvest storage on the chemical and microstructural characteristics of the common bean (Phaseolus vulgaris L.).

Hard to cook is a textural defect that affects the nutritional quality of beans stored under adverse temperature and humidity conditions. This defect is related to intrinsic characteristics such as seed coat thickness, composition and microstructure. The aim of the present study was to evaluate the chemical and microstructural characteristics of common bean (Phaseolus vulgaris L.) during 270 days of post-harvest storage at 30 °C and 70% relative humidity. Microstructural analysis revealed alteration of the cotyledon cell wall and seed coat affecting seed viability and restricting seedling emergence. The seed coat thickness contraction from 105.79 µm to 97.35 µm (270 days). Changes are related with the protein bodies migration from cotyledons to seed coat. An increase in neutral detergent fiber and the presence of CaOx crystals were observed, which confer rigidity to the seed coat and affect water diffusion after 150 days causing permeability changes that contributed to seed hardening.

T and Z, partial seed coat patterning genes in common bean, provide insight into the structure and protein interactions of a plant MBW complex.

Flavonoids are secondary metabolites associated with plant seed coat and flower color. These compounds provide health benefits to humans as anti-inflammatory and antioxidant compounds. The expression of the late biosynthetic genes in the flavonoid pathway is controlled by a ternary MBW protein complex consisting of interfacing MYB, beta-helix-loop-helix (bHLH), and WD40 Repeat (WDR) proteins. P, the master regulator gene of the flavonoid expression in common bean (Phaseolus vulgaris L.), was recently determined to encode a bHLH protein. The T and Z genes control the distribution of color in bean seeds and flowers and have historically been considered regulators of the flavonoid gene expression. T and Z candidates were identified using reverse genetics based on genetic mapping, phylogenetic analysis, and mutant analysis. Domain and AlphaFold2 structure analyses determined that T encodes a seven-bladed ß-propeller WDR protein, while Z encodes a R2R3 MYB protein. Deletions and SNPs in T and Z mutants, respectively, altered the 3D structure of these proteins. Modeling of the Z MYB/P bHLH/T WDR MBW complex identified interfacing sequence domains and motifs in all three genes that are conserved in dicots. One Z MYB motif is a possible beta-molecular recognition feature (ß-MoRF) that only appears in a structured state when Z MYB is modeled as a component of a MBW complex. Complexes containing mutant T and Z proteins changed the interaction of members of the complex in ways that would alter their role in regulating the expression of genes in the flavonoid pathway.

Seed color patterns in domesticated common bean are regulated by MYB-bHLH-WD40 transcription factors and temperature.

Seed colors and color patterns are critical for the survival of wild plants and the consumer appeal of crops. In common bean, a major global staple, these patterns are also essential in determining market classes, yet the genetic and environmental control of many pigmentation patterns remains unresolved. In this study, we genetically mapped variation for several important seed pattern loci, including T, Bip, phbw, and Z, which co-segregated with candidate genes PvTTG1, PvMYC1, PvTT8, and PvTT2, respectively. Proteins encoded by these genes are predicted to work together in MYB-bHLH-WD40 (MBW) complexes, propagating flavonoid biosynthesis across the seed coat as observed in Arabidopsis. Whole-genome sequencing of 37 accessions identified mutations, including seven unique parallel mutations in T (PvTTG1) and non-synonymous SNPs in highly conserved residues in bipana (PvMYC1) and z (PvTT2). A 612 bp intron deletion in phbw (PvTT8) eliminated motifs conserved since the Papilionoideae origin and corresponded to a 20-fold reduction in transcript abundance. In multi-location field trials of seven varieties with partial seed coat pigmentation patterning, the pigmented seed coat area correlated positively with ambient temperature, with up to 11-fold increases in the pigmented area from the coolest to the warmest environments. In controlled growth chamber conditions, an increase of 4°C was sufficient to cause pigmentation on an average additional 21% of the seed coat area. Our results shed light on key steps of flavonoid biosynthesis in common bean. They will inform breeding efforts for seed coat color/patterning to improve consumer appeal in this nutritious staple crop.

PvMYB60 gene, a candidate for drought tolerance improvement in common bean in a climate change context.

BACKGROUND: Common bean (Phaseolus vulgaris) is one of the main nutritional resources in the world, and a low environmental impact source of protein. However, the majority of its cultivation areas are affected by drought and this scenario is only expected to worsen with climate change. Stomatal closure is one of the most important plant responses to drought and the MYB60 transcription factor is among the key elements regulating stomatal aperture. If targeting and mutating the MYB60 gene of common bean would be a valuable strategy to establish more drought-tolerant beans was therefore investigated. RESULTS: The MYB60 gene of common bean, with orthology to the Arabidopsis AtMYB60 gene, was found to have conserved regions with MYB60 typical motifs and architecture. Stomata-specific expression of PvMYB60 was further confirmed by q-RT PCR on organs containing stomata, and stomata-enriched leaf fractions. Further, function of PvMYB60 in promoting stomata aperture was confirmed by complementing the defective phenotype of a previously described Arabidopsis myb60-1 mutant. CONCLUSIONS: Our study finally points PvMYB60 as a potential target for obtaining more drought-tolerant common beans in the present context of climate change which would further greatly contribute to food security particularly in drought-prone countries.

Comparative Effects of Water Scarcity on the Growth and Development of Two Common Bean (Phaseolus vulgaris L.) Genotypes with Different Geographic Origin (Mesoamerica/Andean).

Drought stress is widely recognized as a highly detrimental abiotic stress factor that significantly impacts crop growth, development, and agricultural productivity. In response to external stimuli, plants activate various mechanisms to enhance their resistance or tolerance to abiotic stress. The common bean, a most important legume according to the FAO, serves as a staple food for millions of people worldwide, due to its rich protein, carbohydrate, and fiber content, concurrently, and water scarcity is the main factor limiting common bean production. The process of domestication and on-farm conservation has facilitated the development of genotypes with varying degrees of drought stress resistance. Consequently, using landraces as biological material in research can lead to the identification of variants with superior resistance qualities to abiotic stress factors, which can be effectively integrated into breeding programs. The central scope of this research was to find out if different geographic origins of common bean genotypes can determine distinct responses at various levels. Hence, several analyses were carried out to investigate responses to water scarcity in three common bean genotypes, M-2087 (from the Mesoamerican gene pool), A-1988 (from the Andean gene pool) and Lechinta, known for its high drought stress resistance. Plants were subjected to different water regimes, followed by optical assessment of the anatomical structure of the hypocotyl and epicotyl in each group; furthermore, the morphological, physiological, and biochemical parameters and molecular data (quantification of the relative expression of the thirteen genes) were assessed. The three experimental variants displayed distinct responses when subjected to 12 days of water stress. In general, the Lechinta genotype demonstrated the highest adaptability and drought resistance. The M-2087 landrace, originating from the Mesoamerican geographic basin, showed a lower resistance to water stress, compared to the A-1988 landrace, from the Andean basin. The achieved results can be used to scale up future research about the drought resistance of plants, analyzing more common bean landraces with distinct geographic origins (Mesoamerican/Andean), which can then be used in breeding programs.

Development of yogurt fortified with four varieties of common bean (Phaseolus vulgaris) whey by using response surface methodology: a preliminary study.

In recent years, there has been a growing interest in developing novel foods with improved health and nutritional characteristics, particularly through the supplementation and development of dairy products with plant-based ingredients. In this study, the response surface methodology (RSM) was employed to optimize the ingredient formulation and processing parameters of common bean whey-fortified yogurt (CBWFY) production containing Lactobacillus bulgaricus, and common bean whey (CBW) with a high probiotic count, superior physicochemical and textural properties, and desirable sensory attributes. The experiments were planned using the "box-Behnken design" (BBD) with three independent variables: fermentation time (0-10 h), common bean ratio (25-100%), and the amount of starter culture (1-5%). To assess the physicochemical properties of the yogurt, such as pH, titratable acidity, viable cell count, and syneresis of the CBWFY, they were determined and optimized. In all the common bean whey samples, the optimum conditions were obtained by supplementing cow milk with 25% common bean whey (CBW), an inoculation ratio of 1-4%, and fermentation for 5.54 h. Fermentation time and CBW concentration significantly affected the viability of L. bulgaricus and the physicochemical attributes of yogurt. This study demonstrated that the addition of cow milk with 25% CBW from the white bean variety produced probiotic yogurt with the highest L. bulgaricus population (up to 8.55 log CFU/mL) compared to the other varieties and an enhancement in the yogurt's pH and acidity, while a decrease in yogurt syneresis occurred. In general, the results of the current study showed that adding up to 25% white common bean whey to probiotic yogurt can be an option for producing yogurt with potential functional and sensory quality. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05876-z.

Unearthing Optimal Symbiotic Rhizobia Partners from the Main Production Area of Phaseolus vulgaris in Yunnan.

Phaseolus vulgaris is a globally important legume cash crop, which can carry out symbiotic nitrogen fixation with rhizobia. The presence of suitable rhizobia in cultivating soils is crucial for legume cropping, especially in areas beyond the plant-host native range, where soils may lack efficient symbiotic partners. We analyzed the distribution patterns and traits of native rhizobia associated with P. vulgaris in soils of Yunnan, where the common bean experienced a recent expansion. A total of 608 rhizobial isolates were tracked from soils of fifteen sampling sites using two local varieties of P. vulgaris. The isolates were discriminated into 43 genotypes as defined by IGS PCR-RFLP. Multiple locus sequence analysis based on recA, atpD and rpoB of representative strains placed them into 11 rhizobial species of Rhizobium involving Rhizobium sophorae, Rhizobium acidisoli, Rhizobium ecuadorense, Rhizobium hidalgonense, Rhizobium vallis, Rhizobium sophoriradicis, Rhizobium croatiense, Rhizobium anhuiense, Rhizobium phaseoli, Rhizobium chutanense and Rhizobium etli, and five unknown Rhizobium species; Rhizobium genosp. I~V. R. phaseoli and R. anhuiense were the dominant species (28.0% and 28.8%) most widely distributed, followed by R. croatiense (14.8%). The other rhizobial species were less numerous or site-specific. Phylogenies of nodC and nifH markers, were divided into two specific symbiovars, sv. phaseoli regardless of the species affiliation and sv. viciae associated with R. vallis. Through symbiotic effect assessment, all the tested strains nodulated both P. vulgaris varieties, often resulting with a significant greenness index (91-98%). However, about half of them exhibited better plant biomass performance, at least on one common bean variety, and two isolates (CYAH-6 and BLYH-15) showed a better symbiotic efficiency score. Representative strains revealed diverse abiotic stress tolerance to NaCl, acidity, alkalinity, temperature, drought and glyphosate. One strain efficient on both varieties and exhibiting stress abiotic tolerance (BLYH-15) belonged to R. genosp. IV sv. phaseoli, a species first found as a legume symbiont.

Sampling strategies for genotyping common bean (Phaseolus vulgaris L.) Genebank accessions with DArTseq: a comparison of single plants, multiple plants, and DNA pools.

Introduction: Genotyping large-scale gene bank collections requires an appropriate sampling strategy to represent the diversity within and between accessions. Methods: A panel of 44 common bean (Phaseolus vulgaris L.) landraces from the Alliance Bioversity and The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT) gene bank was genotyped with DArTseq using three sampling strategies: a single plant per accession, 25 individual plants per accession jointly analyzed after genotyping (in silico-pool), and by pooling tissue from 25 individual plants per accession (seq-pool). Sampling strategies were compared to assess the technical aspects of the samples, the marker information content, and the genetic composition of the panel. Results: The seq-pool strategy resulted in more consistent DNA libraries for quality and call rate, although with fewer polymorphic markers (6,142 single-nucleotide polymorphisms) than the in silico-pool (14,074) or the single plant sets (6,555). Estimates of allele frequencies by seq-pool and in silico-pool genotyping were consistent, but the results suggest that the difference between pools depends on population heterogeneity. Principal coordinate analysis, hierarchical clustering, and the estimation of admixture coefficients derived from a single plant, in silico-pool, and seq-pool successfully identified the well-known structure of Andean and Mesoamerican gene pools of P. vulgaris across all datasets. Conclusion: In conclusion, seq-pool proved to be a viable approach for characterizing common bean germplasm compared to genotyping individual plants separately by balancing genotyping effort and costs. This study provides insights and serves as a valuable guide for gene bank researchers embarking on genotyping initiatives to characterize their collections. It aids curators in effectively managing the collections and facilitates marker-trait association studies, enabling the identification of candidate markers for key traits.

Native Mexican black bean purified anthocyanins fractionated by high-performance counter-current chromatography modulate inflammatory pathways.

In addition to their pigment properties, the potential health benefits of anthocyanins have made them a subject of interest in recent years. This study aimed to obtain purified anthocyanin fractions from native Mexican black bean cultivars using Amberlite XAD-7 resin column and HPCCC and evaluate their anti-inflammatory properties using RAW 264.7 cells. The major anthocyanins in the purified anthocyanin fractions were delphinidin 3-glucoside (61.8%), petunidin 3-glucoside (25.2%), and malvidin 3-glucoside (12.2%). Purified anthocyanin fractions at 12.5 µg/mL effectively prevented LPS-induced ERK1/ERK2 phosphorylation and reduced the protein expression of COX-2 and mRNA expression of iNOS. Results showed that purified anthocyanin fractions have the potential to modulate the inflammatory response by inhibiting the production of pro-inflammatory mediators through the ERK1/ERK2 and NF-κB pathways. This study suggests that anthocyanins from black beans could be used as a natural strategy to help modulate inflammation-associated diseases.

Conventional management has a greater negative impact on Phaseolus vulgaris L. rhizobia diversity and abundance than water scarcity.

Introduction: Drought is one of the biggest problems for crop production and also affects the survival and persistence of soil rhizobia, which limits the establishment of efficient symbiosis and endangers the productivity of legumes, the main source of plant protein worldwide. Aim: Since the biodiversity can be altered by several factors including abiotic stresses or cultural practices, the objective of this research was to evaluate the effect of water availability, plant genotype and agricultural management on the presence, nodulation capacity and genotypic diversity of rhizobia. Method: A field experiment was conducted with twelve common bean genotypes under irrigation and rain-fed conditions, both in conventional and organic management. Estimation of the number of viable rhizobia present in soils was performed before the crop establishment, whereas the crop yield, nodule number and the strain diversity of bacteria present in nodules were determined at postharvest. Results: Rainfed conditions reduced the number of nodules and of isolated bacteria and their genetic diversity, although to a lesser extent than the agrochemical inputs related to conventional management. In addition, the effect of water scarcity on the conventional management soil was greater than observed under organic conditions. Conclusions: The preservation of diversity will be a key factor to maintain crop production in the future, as problems caused by drought will be exacerbated by climate change and organic management can help to maintain the biodiversity of soil microbiota, a fundamental aspect for soil health and quality.

Fatty Acids in Dry Beans (Phaseolus vulgaris L.): A Contribution to Their Analysis and the Characterization of a Diversity Panel.

Dry bean (Phaseolus vulgaris L.) is a crop of high nutritional interest widespread throughout the world. This research had two objectives. On the one hand, the development and validation of an analytical method to quantify fatty acids in dry beans based on the extraction and derivatization in a single step and later quantification by gas chromatography. On the other, its application to characterize the fatty acid content in a diversity panel consisting of 172 lines. The method was successfully validated in terms of accuracy, precision and robustness. Among the 14 fatty acids that constitute the fatty acid profile of dry bean, the most quantitatively important were linolenic acid, the major fatty acid in all cases, with an average value of 6.7 mg/g, followed by linoleic acid (3.9 mg/g), palmitic acid (2.9 mg/g) and oleic acid (1.5 mg/g). The concentrations of fatty acids in dry bean were influenced by the gene pool, with the Mesoamerican gene pool showing a higher content of palmitic, stearic, linoleic and linolenic acids and the Andean gene pool a higher level of cis-vaccenic acid. Also, the expression of fatty acid content showed high heritability. The information generated constitutes a robust database of interest in food technology, nutrition and breeding programs.

The Kirkhouse Trust: Successes and Challenges in Twenty Years of Supporting Independent, Contemporary Grain Legume Breeding Projects in India and African Countries.

This manuscript reviews two decades of projects funded by the Kirkhouse Trust (KT), a charity registered in the UK. KT was established to improve the productivity of legume crops important in African countries and in India. KT's requirements for support are: (1) the research must be conducted by national scientists in their home institution, either a publicly funded agricultural research institute or a university; (2) the projects need to include a molecular biology component, which to date has mostly comprised the use of molecular markers for the selection of one or more target traits in a crop improvement programme; (3) the projects funded are included in consortia, to foster the creation of scientific communities and the sharing of knowledge and breeding resources. This account relates to the key achievements and challenges, reflects on the lessons learned and outlines future research priorities.