Biology subjects

Maledon, E.

Publications and source records attributed to Maledon, E..

4 recordsLinked to original sources

bioRxiv2023

Detecting the genetic variants associated with key culinary traits in Dioscorea alata

Quality attributes play a pivotal role in determining consumers acceptability and market value of food crops. Dioscorea alata is a major yam species for food security in tropical areas, but our understanding of the genetic factors underlying tuber culinary traits is limited. This study aimed at elucidating the genetic basis of key culinary attributes, including dry matter content, cooking time, boiled yam hardness, and moldability, through genome-wide association studies (GWAS). Phenotypic assessments revealed notable variations among the D. alata genotypes across two locations as well as significant correlations among the quality traits. The GWAS identified 25 significant associations distributed across 14 chromosomes. Allele segregation analysis of the identified loci highlighted favorable alleles associated with desired traits, such as reduced cooking time, increased dry matter content, enhanced hardness, and good moldability. Within the set of 42 putative candidate genes, we identified specific genes differentially expressed in tubers of distinct genotypes with contrasting quality attributes. Furthermore, we conducted a comparative analysis with previously reported quantitative trait loci for dry matter content and showed that multiple genomic regions govern this trait in D. alata. Our study offers valuable insights into the links between these key culinary traits and the underlying genetic basis in D. alata. These findings have practical implications for breeding programs aimed at enhancing the quality attributes of greater yam.

plant biology↗

bioRxiv2023

Genome-wide association studies reveal novel loci controlling tuber flesh color and oxidative browning in Dioscorea alata

BackgroundConsumers preferences for food crops are guided by quality attributes. This study aimed at deciphering the genetic basis of quality traits, especially tuber flesh color (FC) and oxidative browning (OB) in Dioscorea alata, based on the genome-wide association studies (GWAS) approach. The D. alata panel was planted at two locations in Guadeloupe. At harvest, the FC was scored visually as white, cream, or purple on longitudinally sliced mature tubers. The OB was scored visually as the presence or absence of browning after 15 minutes of exposure of the sliced samples to ambient air. ResultsPhenotypic characterization for FC and OB of a diverse panel of D. alata genotypes highlighted significant variation within the panel and across two locations. The genotypes within the panel displayed a weak structure and could be classified into 3 subpopulations. GWAS identified 14 and 4 significant associations for tuber FC and OB, respectively, with phenotypic variance, explained values ranging from 7.18 to 18.04%. Allele segregation analysis at the significantly associated loci highlighted the favorable alleles for the desired traits, i.e., white FC and no OB. A total of 24 putative candidate genes were identified around the significant signals. A comparative analysis with previously reported quantitative trait loci indicated that numerous genomic regions control these traits in D. alata. ConclusionOur study provides important insights into the genetic control of tuber FC and OB in D. alata. The major and stable loci can be further utilized to improve selection in breeding programs for developing new cultivars with enhanced tuber quality.

genetics↗

bioRxiv2023

First report of a successful development of yam hybrids (Dioscorea alata L.) from lyophilized and long-term stored pollens

BackgroundGreater yam, Dioscorea alata L., is a significant food security crop in tropical areas. However, low genetic diversity and various biological constraints, including susceptibility to viruses, ploidy, erratic and low flowering intensity, and asynchronous flowering hinder successful hybrid development and genetic gains in greater yam breeding programs. Therefore, pollen storage has gained much attention to facilitate genetic material exchanges, artificial pollinations and to increase the genetic gains in breeding programs. This 4-year study aimed at developing a practical long-term pollen storage technique for the successful development of yam hybrids. Fresh pollens were collected from two D. alata males, then lyophilized (two lyophilization treatments were applied), followed by storage at room temperature (24-25 {degrees}C) for 12 months. Moreover, the lyophilized and stored pollens were tested for viability by crossing with four female varieties. ResultsOur results showed that lyophilization is effective for achieving viable pollens after 12 months of storage. Treatment 1 (48 h drying) showed higher pollen germination and fertility rates than Treatment 2 (72 h drying). Although we observed a reduction in viability of lyophilized pollens after 12 months of storage, we generated hybrid seedlings with success rates from 12 to 21% compared to 21-31% when using fresh pollens. Paternity testing based on molecular genotyping confirmed the hybrid status of the obtained seedlings, which grew well in a greenhouse. ConclusionsThe results signify the importance of pollen lyophilization for yam breeding programs.

plant biology↗

bioRxiv2023

Genome-wide development of intra- and inter-specific transferable SSR markers and construction of a dynamic web resource for yam molecular breeding: Y2MD

BackgroundMicrosatellite markers represent a low-cost and efficient tool for rapid genotyping as compared to single nucleotide polymorphism markers in laboratories with limited resources. For the economically important yam species widely cultivated in developing countries, very few microsatellite markers are available and no marker database has been developed to date. Herein, we conducted a genome-wide microsatellite marker development among four yam species, identified cross-species transferable markers, and designed an easy-to-use web portal for the yam breeder community. ResultsThe screening of yam genomes resulted in 318,713; 322,501; 307,040 and 253,856 microsatellites in Dioscorea alata, D. rotundata, D. dumetorum, and D. zingiberensis, respectively. Mono-, di- and tri-nucleotides were the most important types of repeats in the different species and a total of 864,128 primer pairs were designed. Furthermore, we identified 1170 cross-species transferable microsatellite markers. Among them, a subset of 17 markers were experimentally validated with good discriminatory power regarding the species and the ploidy levels. Ultimately, we created and deployed a dynamic Yam Microsatellite Markers Database (Y2MD) available at http://yamdb.42web.io/. Y2MD is embedded with various useful tools such as JBrowse, Blast, insilicoPCR, and SSR Finder to facilitate the exploitation of microsatellite markers in yams. ConclusionsThe present work is the first comprehensive microsatellite marker mining across several yam species and will contribute to advance yam genetic research and marker-assisted breeding. The released user-friendly database constitutes a valuable platform for yam breeders, especially those in developing countries.

genomics↗