Mapping quantitative trait loci affecting biochemical and morphological fruit properties in eggplant (Solanum melongena L.)

Eggplant berries are a source of health-promoting metabolites including antioxidant and nutraceutical compounds, mainly anthocyanins and chlorogenic acid; however, they also contain some anti-nutritional compounds such as steroidal glycoalkaloids (SGA) and saponins, which are responsible for the bitter taste of the flesh and with potential toxic effects on humans. Up to now, Quantitative Trait Loci (QTL) for the metabolic content are far from being characterized in eggplant, thus hampering the application of breeding programs aimed at improving its fruit quality. Here we report on the identification of some QTL for the fruit metabolic content in an F2 intraspecific mapping population of 156 individuals, obtained by crossing the eggplant breeding lines ‘305E40’ x ‘67/3’. The same population was previously employed for the development of a RAD-tag based linkage map and the identification of QTL associated to morphological and physiological traits. The mapping population was biochemically characterized for both fruit basic qualitative data, like dry matter, °Brix, sugars and organic acids, as well as for health-related compounds such chlorogenic acid, (the main flesh monomeric phenol), the two peel anthocyanins (i.e. delphinidin-3-rutinoside (D3R) and delphinidin-3-(p-coumaroylrutinoside)-5-glucoside (nasunin)) and the two main steroidal glycoalkaloids, solasonine and solamargine. For most of the traits, one major QTL (PVE ≥ 10%) was spotted and putative orthologies with other Solanaceae crops are discussed. The present results supply valuable information to eggplant breeders on the inheritance of key fruit quality traits, thus providing potential tools to assist future breeding programs

Antinutritional factors, nutritional improvement, and future food use of common beans : a perspective

Common bean seeds are an excellent source of protein as well as of carbohydrates, minerals, vitamins, and bioactive compounds reducing, when in the diet, the risks of diseases. The presence of bioactive compounds with antinutritional properties (e.g., phytic acid, lectins, raffinosaccharides, protease inhibitors) limits, however, the bean’s nutritional value and its wider use in food preparations. In the last decades, concerted efforts have been, therefore, made to develop new common bean genotypes with reduced antinutritional compounds by exploiting the natural genetic variability of common bean and also applying induced mutagenesis. However, possible negative, or positive, pleiotropic effects due to these modifications, in terms of plant performance in response to stresses or in the resulting technological properties of the developed mutant genotypes, have yet not been thoroughly investigated. The purpose of the perspective paper is to first highlight the current advances, which have been already made in mutant bean characterization. A view will be further provided on future research directions to specifically explore further advantages and disadvantages of these bean mutants, their potential use in innovative foods and representing a valuable genetic reservoir of combinations to assess the true functional role of specific seed bioactive components directly in the food matrix.The ERA-NET co-funding on Food Systems and Climate (FOSC) BIO-BELIEF project.https://www.frontiersin.org/journals/plant-sciencedm2022Plant Production and Soil Scienc

An Eggplant Recombinant Inbred Population Allows the Discovery of Metabolic QTLs Controlling Fruit Nutritional Quality

Eggplant (Solanum melongena L.) represents the third most important crop of the Solanaceae family and is an important component of our daily diet. A population of 164 F6 recombinant inbred lines (RILs), derived from two eggplant lines differing with respect to several key agronomic traits, “305E40” and “67/3,” was grown to the commercial maturation stage, and fruits were harvested, separated into peel and flesh, and subjected to liquid chromatography Liquid Chromatography/Mass Spectrometry (LC/MS) analysis. Through a combination of untargeted and targeted metabolomics approaches, a number of metabolites belonging to the glycoalkaloid, anthocyanin, and polyamine classes and showing a differential accumulation in the two parental lines and F1 hybrid were identified. Through metabolic profiling of the RILs, we identified several metabolomic quantitative trait loci (mQTLs) associated with the accumulation of those metabolites. Each of the metabolic traits proved to be controlled by one or more quantitative trait loci (QTLs); for most of the traits, one major mQTL (phenotypic variation explained [PVE] ≥ 10%) was identified. Data on mQTL mapping and dominance–recessivity relationships of measured compounds in the parental lines and F1 hybrid, as well as an analysis of the candidate genes underlying the QTLs and of their sequence differences in the two parental lines, suggested a series of candidate genes underlying the traits under study

A guard-cell-specific MYB transcription factor regulates stomatal movements and plant drought tolerance

Stomatal pores located on the plant epidermis regulate CO2 uptake for photosynthesis and the loss of water by transpiration. The opening and closing of the pore is mediated by turgor-driven volume changes of two surrounding guard cells [1]. These highly specialized cells integrate internal signals and environmental stimuli to modulate stomatal aperture for plant survival under diverse conditions [2]. Modulation of transcription and mRNA processing play important roles in controlling guard-cell activity, although the details of these levels of regulation remain mostly unknown [3-5]. Here we report the characterization of AtMYB60, a R2R3-MYB gene of Arabidopsis, as the first transcription factor involved in the regulation of stomatal movements. AtMYB60 is specifically expressed in guard cells, and its expression is negatively modulated during drought. A null mutation in AtMYB60 results in the constitutive reduction of stomatal opening and in decreased wilting under water stress conditions. Transcript levels of a limited number of genes are altered in the mutant, and many of these genes are involved in the plant response to stress, Our data indicate that AtMYB60 is a transcriptional modulator of physiological responses in guard cells and open new possibilities to engineering stomatal activity to help plants survive desiccation

Data from: Retrotransposon proliferation coincident with the evolution of dioecy in asparagus

Current phylogenetic sampling reveals that dioecy and an XY sex chromosome pair evolved once or possibly twice in the genus Asparagus. Although there appear to be some lineage-specific polyploidization events, the base chromosome number of 2n=2x=20 is relatively conserved across the Asparagus genus. Regardless, dioecious species tend to have larger genomes than hermaphroditic species. Here we test whether this genome size expansion in dioecious species is related to a polyploidization and subsequent chromosome fusion or retrotransposon proliferation in dioecious species. We first estimate genome sizes or use published values for four hermaphrodites and four dioecious species distributed across the phylogeny and show that dioecious species typically have larger genomes than hermaphroditic species. Utilizing a phylogenomic approach we find no evidence for ancient polyploidization contributing to increased genome sizes of sampled dioecious species. We do find support for an ancient whole genome duplication event predating the diversification of the Asparagus genus. Repetitive DNA content of the four hermaphroditic and four dioecious species was characterized based on randomly sampled whole genome shotgun sequencing and common elements were annotated. Across our broad phylogenetic sampling, Ty-1 Copia retroelements in particular have undergone a marked proliferation in dioecious species. In the absence of a detectable whole genome duplication event, retrotransposon proliferation is the most likely explanation for the precipitous increase in genome size in dioecious Asparagus species

A cystine-knot miniprotein from tomato fruit inhibits endothelial cell migration and angiogenesis by affecting vascular endothelial growth factor receptor (VEGFR) activation and nitric oxide production

Scope: Cystine-knot miniproteins are bioactive molecules with a broad range of potential therapeuticapplications. Recently, it was demonstrated that two tomato cystine-knot miniproteins(TCMPs) exhibit in vitro antiangiogenic activity on human umbilical vein cells. The aim of thepresent study was to investigate the effects of a fruit-specific cystine-knot miniprotein of tomatoon in vitro endothelial cell migration and in vivo angiogenesis using a zebrafish model.Methods and results: The cystine-knot protein purified from tomato fruits using gel filtration LCand RP-HPLC inhibited cell migration when tested at 200 nM using the wound healing assay,and reduced nitric oxide formation probed by 4-amino-5-methylamino-27-difluorofluoscescindiacetate. RT-PCR and Western blot analyses demonstrated that vascular endothelium growthfactor A dependent signaling was the target of TCMP bioactivity. Angiogenesis was inhibitedin vivo in zebrafish embryos treated with 500 nM TCMP.Conclusion: Our results demonstrate that cystine-knot miniproteins present inmature tomatofruits are endowed with antiangiogenic activity in vitro and in vivo. These moleculesmay conferbeneficial effects to tomato dietary intake, along with lycopene and other antioxidants. Furtherinvestigation is warranted to explore the potential of these compounds as model scaffolds forthe development of new drugs