Biology subjects

Prohens, J.

Publications and source records attributed to Prohens, J..

26 records · Page 2Linked to original sources

bioRxiv2023

Evaluation of three sets of advanced backcrosses of eggplant with wild relatives from different genepools under low N fertilization conditions

The development of new cultivars with improved nitrogen use efficiency (NUE) is key for implementing sustainable agriculture practices. Crop wild relatives (CWRs) provide valuable genetic resources for breeding programs aimed at achieving this goal. In this study, three eggplant (Solanum melongena) accessions together with their advanced backcrosses (ABs; BC3 to BC5 generations) with introgressions from the wild relatives S. insanum, S. dasyphyllum, and S. elaeagnifolium were evaluated for 22 morpho-agronomic, physiological, and N use efficiency (NUE) traits under low nitrogen fertilization conditions. The three S. melongena recurrent parents were also evaluated under control (normal) N fertilization. Reduction of N fertilization in the parents resulted in decreased chlorophyll content-related traits, aerial biomass, stem diameter and yield, and increased NUE, nitrogen uptake efficiency (NUpE), and nitrogen utilization efficiency (NUtE). However, the decrease in yield was moderate, ranging between 62.6% and 72.6%. A high phenotypic variation was observed within each of the three sets of ABs under low nitrogen conditions, with some individuals displaying improved transgressive characteristics over the recurrent parents. Genotyping with the SPET 5k probes platform revealed a high, although variable, degree of recovery of the recurrent parent genome in the ABs and allowed the identification of 16 QTLs. Different allelic effects were observed for the introgressed QTL alleles. Several candidate genes were identified in the QTL regions associated with plant growth, yield, fruit size, and NUE-related parameters. Our results show that eggplant materials with introgressions from CWRs can result in a dramatic impact in eggplant breeding for a more sustainable agriculture.

genetics↗

bioRxiv2023

Evaluation of a set of eggplant (Solanum melongena) lines with introgressions of S. incanum under water stress conditions

As access to irrigation water becomes increasingly limited, introgression of relevant genomic regions from drought-tolerant wild genotypes is a promising breeding strategy for crop plants. In this study, nine eggplant (Solanum melongena) introgression lines (ILs) covering altogether 71.6% of the genome of the donor wild relative parent S. incanum were evaluated for drought tolerance under water stress conditions. Plants at the five true leaves stage were irrigated at either 100% (control) or 30% (water stress) field capacity for 14 days, and growth and biochemical traits were measured. Reduced irrigation resulted in decreased growth and increased levels of stress markers such as proline and malondialdehyde. Most ILs had lower growth and biomass production than the cultivated parent under both conditions. However, the wild alleles for two QTLs related to stem and root dry weight (dwt8 and dwr6%) conferred improved tolerance to water stress. In addition, several S. incanum alleles had a positive effect on important traits that may improve yield under drought conditions, such as leaf water content (lwc12%), water use efficiency (wue1%) and chlorophyll content (chl2 and chl8%). Fine-mapping of the QTLs for tolerance and reducing linkage drag with regions affecting growth will be crucial for significantly improving eggplant drought tolerance through introgression breeding.

genetics↗

bioRxiv2023

Agronomic treatments combined with embryo rescue for rapid generation advancement in tomato speed breeding

Unlike other major crops, little research has been performed on tomato for reducing generation time for speed breeding. We evaluated several agronomic treatments for reducing the generation time of tomato in the M82 (determinate) and Moneymaker (indeterminate) varieties and evaluated the best combination in conjunction with embryo rescue. In a first experiment under the autumn cycle, five container sizes, from 0.2 1 (XS) to 6 1 (XL), were evaluated. We found that plants from the XL containers exhibited better development and required less time from sowing to anthesis (DSA) and for anthesis to fruit ripening (DAR). In a second experiment, using XL containers in the autumn-winter cycle, we evaluated cold priming at the cotyledonary stage, water stress, P supplementation, and K supplementation on generation time. We found that, compared to the control, cold priming significantly reduced the number of leaves and plant height to first inflorescence as well as DSA (2.7 d), while K supplementation reduced DAR (8.8 d). No effects of these treatments were observed for other growth of physiological traits. In a third experiment with XL containers in the spring-summer cycle, the combination of cold priming plus K supplementation was tested, confirming the significant effect of the combination on generation time (2.9 d for DSA and 3.9 d for DAR). Embryo rescue during the cell expansion cycle (average of 22.0 d and 23.3 d after anthesis for M82 and Moneymaker, respectively) allowed shortening the generation time by 8.7 d in M82 and 11.6 d in Moneymaker compared to the in planta fruit ripening. The combination of agronomic treatments with embryo rescue can make an effective contribution to increase the number of generations per year for speed breeding in tomato from the current three to four.

plant biology↗

bioRxiv2022

Transcriptome profiles of eggplant (Solanum melongena) and its wild relative S. dasyphyllum under different levels of osmotic stress provide insights into response mechanisms to drought

Defence mechanisms to abiotic stresses, like drought, are very broad and RNA sequencing (RNA-Seq) can help in understanding the complex responses triggered. In this study, we performed RNA-Seq of the transcriptomes of eggplant (Solanum melongena) and its related wild species (S. dasyphyllum) under two PEG concentrations (20% and 30%), two different times (after 0.5 h and 2 h of osmotic stress) and at two plant phenological stages (three and five true fully developed leaves). Solanum dasyphyllum was more tolerant to osmotic stress, and a differential expression pattern of drought-related genes was identified between the two species. Plants subjected to a higher osmotic potential, at a more adult stage and at a higher stress exposure time displayed a higher number of DEGs (differential expressed genes). Gene ontology (GO) enrichment analysis revealed that, compared to S. melongena, S. dasyphyllum triggered the regulation of a wide range of transcription factors (AP2/ERF, DREB, bZIP, WRKY and bHLH). In both species, the abscisic acid (ABA) signaling response pathway played a crucial role leading to stomatal closure. Other important pathways involved in abiotic stresses tolerance including flavonoid, carotenoid and phenylpropanoid biosynthesis, chlorophyll metabolism and photosynthesis pathway among others were found to have a relevant role under both moderate and severe osmotic stresses. Our results reveal that S. dasyphyllum is a potential source of genes for breeding resilient eggplant varieties.

genetics↗

bioRxiv2022

Mutations in the SmAPRR2 transcription factor suppressing chlorophyll pigmentation in the eggplant fruit peel are key drivers of a diversified colour palette

Understanding the mechanisms by which chlorophylls are synthesized in the eggplant (Solanum melongena) fruit peel is of great relevance for eggplant breeding. A multi-parent advanced generation inter-cross (MAGIC) population and a germplasm collection have been screened for green pigmentation in the fruit peel and used to identify candidate genes for this trait. A genome-wide association study (GWAS) performed with 420 MAGIC individuals revealed a major association on chromosome 8 close to a gene similar to APRR2. Two variants in SmAPRR2, predicted as having a high impact effect, were associated with the absence of fruit chlorophyll pigmentation in the MAGIC population, and a large deletion of 5.27 kb was found in two reference genomes of accessions without chlorophyll in the fruit peel. The validation of the candidate gene SmAPRR2 was performed by its sequencing in a set of MAGIC individuals and through its de novo assembly in 277 accessions from the G2P-SOL eggplant core collection. Two additional mutations in SmAPRR2 associated with the lack of chlorophyll were identified in the core collection set. The phylogenetic analysis of APRR2 reveals orthology within Solanaceae and suggests that specialization of APRR2-like genes occurred independently in Cucurbitaceae and Solanaceae. A strong geographical differentiation was observed in the frequency of predominant mutations in SmAPRR2, resulting in a lack of fruit chlorophyll pigmentation and suggesting that this phenotype may have arisen and been selected independently several times. This study represents the first identification of a major gene for fruit chlorophyll pigmentation in the eggplant fruit.

genetics↗

bioRxiv2021

European Vintage tomatoes galore: a result of farmers combinatorial assorting/swapping of a few diversity rich loci

A comprehensive collection of 1,254 tomato accessions corresponding to European heirlooms and landraces, together with modern varieties, early domesticates and wild relatives, were analyzed by genotyping by sequencing. A continuous genetic gradient between the vintage and modern varieties was observed. European vintage tomatoes displayed very low genetic diversity, with only 298 loci out of 64,943 variants being polymorphic at the 95% threshold. European vintage tomatoes could be classified in several genetic groups. Two main clusters consisting of Spanish and Italian accessions showed a higher genetic diversity than the rest varieties, suggesting that these regions might be independent secondary centers of diversity and with a different history. Other varieties seem to be the result of a more recent complex pattern of migrations and hybridizations among the European regions. Several polymorphic loci were associated in a GWAS with fruit morphological traits in the European vintage collection, and the corresponding alleles were found to contribute to the distinctive phenotypic characteristic of the genetic varietal groups. The few highly polymorphic loci associated with morphological traits in an otherwise diversity-poor genome suggests a history of balancing selection, in which tomato farmers maintained the morphological variation by applying a high selective pressure within different varietal types. HighlightThe high phenotypic diversity observed among European vintage varieties was created by traditional farmers by combining very few polymorphic loci subjected to balancing selection.

plant biology↗

bioRxiv2021

Newly developed MAGIC population allows identification of strong associations and candidate genes for anthocyanin pigmentation in eggplant

MAGIC populations facilitate the genetic dissection of complex quantitative traits in plants and are valuable breeding materials. We report the development of the first eggplant MAGIC population (S3MEGGIC; 8-way), constituted by 420 S3 individuals developed from the intercrossing of seven cultivated eggplant (Solanum melongena) and one wild relative (S. incanum) parents. The S3MEGGIC recombinant population was genotyped with the eggplant 5k probes SPET platform and phenotyped for anthocyanins presence in vegetative plant tissues (PA) and fruit epidermis (FA), and for the light-sensitive anthocyanic pigmentation under the calyx (PUC). The 7,724 filtered high-confidence SNPs confirmed a low residual heterozygosity (6.87%) and a lack of genetic structure in the S3MEGGIC population, including no differentiation among subpopulations carrying cultivated or wild cytoplasm. Inference of haplotype blocks of the nuclear genome revealed an unbalanced representation of founder genomes, suggesting cryptic selection in favour or against specific parental genomes. GWAS analysis for PA, FA and PUC detected strong associations with two MYB genes similar to MYB113 involved in the anthocyanin biosynthesis pathway and with a COP1 gene, which encodes for a photo-regulatory protein and may be responsible for the PUC phenotype. Evidence was found of a duplication of an ancestral MYB113 gene with a translocation from chromosome 10 to chromosome 1. Parental genotypes for the three genes were in agreement with the candidate genes identification performed in the S3MEGGIC population. Our new eggplant MAGIC population is the largest recombinant population in eggplant and is a powerful tool for eggplant genetics and breeding studies.

genetics↗

bioRxiv2019

Epigenetic bases of grafting-induced vigour in eggplant

In horticulture, grafting is a popular technique used to combine positive traits from two different plants. This is achieved by joining the plant top part (scion) onto a rootstock which contains the stem and roots. Despite its wide use, the biological mechanisms driving rootstock-induced alterations of the scion phenotype remain largely unknown. Given that epigenetics plays a crucial role during distance signalling in plants, we studied the genome-wide changes induced by DNA methylation in eggplant (Solanum melongena) plants grafted onto two interspecific rootstocks used to increase scion vigour. As a control, we compared any epigenetic effect found in such grafts to patterns detected in self-grafted plants. We found that vigour was associated with a specific change in scion gene expression and a genome-wide hypomethylation in CHH context. Interestingly, this hypomethylation correlated with the down-regulation of younger and potentially more active LTR retrotransposons (LTR-TEs), suggesting that graft-induced epigenetic modifications are associated to both physiological and molecular phenotypes in grafted plants. We propose that rootstocks can promote vigour by reducing DNA methylation in the scion genome, following similar principles found in some heterotic hybrids.

plant biology↗