Biology subjects

Vigna, B. B. Z.

Publications and source records attributed to Vigna, B. B. Z..

3 recordsLinked to original sources

bioRxiv2023

Advances in genomic characterization of Urochloa humidicola: exploring polyploid inheritance and apomixis

Tropical forage grasses are an important food source for animal feeding, with Urochloa humidicola, also known as Koronivia grass, being one of the main pasture grasses for poorly drained soils in the tropics. However, genetic and genomic resources for this species are lacking due to its genomic complexity, including high heterozygosity, evidence of segmental allopolyploidy, and reproduction by apomixis. These complexities hinder the application of marker-assisted selection (MAS) in breeding programs. Here, we developed the highest-density linkage map currently available for the hexaploid tropical forage grass U. humidicola. This map was constructed using a biparental F1 population generated from a cross between the female parent H031 (CIAT 26146), the only known sexual genotype for the species, and the apomictic male parent H016 (BRS cv. Tupi). The linkage analysis included 4,873 single nucleotide polymorphism (SNP) markers with allele dosage information. It allowed mapping of the apospory locus and phenotype to linkage group 3, in a region syntenic with chromosome 3 of Urochloa ruziziensis and chromosome 1 of Setaria italica. We also identified hexaploid haplotypes for all individuals, assessed the meiotic configuration, and estimated the level of preferential pairing in parents during the meiotic process, which revealed the autopolyploid origin of sexual H031 in contrast to H016, which presented allopolyploid behavior in preferential pairing analysis. These results provide new information regarding the genetic organization, mode of reproduction, and allopolyploid origin of U. humidicola, potential SNPs markers associated to apomixes for MAS and resources for research on polyploids and tropical forage grasses. Key messageWe present the highest-density genetic map for the hexaploid Urochloa humidicola. SNP markers expose genetic organization, reproduction, and species origin, aiding polyploid and tropical forage research.

genomics↗

bioRxiv2023

Lignin, glutathione and kinases play important roles in Paspalum regnellii defense against spittlebug (Mahanarva spectabilis) attack

Spittlebugs cause large production losses that affect agribusiness worldwide. Understanding plant-herbivore interactions at the molecular level may be the key to developing resistant cultivars. After a nymph survival experiment, root transcriptomes were assembled from two Paspalum regnellii genotypes (BGP 248 and 344) with different first-line defense strategies, with no infestation and at two times after the initial attack of the spittlebug (Mahanarva spectabilis) nymph, thus integrating differential expression analysis and biological network modeling supplemented by root anatomical analysis. Gene Ontology terms related to different stress responses, such as salicylic acid catabolic process, were enriched in BGP 248, while some specific to spittlebugs, such as response to herbivores, were enriched in BGP 344. Enriched pathways were related to structural differences between genotypes, such as those related to cutin, suberin and wax biosynthesis. BGP 344 also presented pathways related to induced defense, such as glutathione metabolism. Metabolic networks highlighted kinases, and coexpression networks demonstrated a complex cascade response that included lncRNAs. This study provides the first molecular insights into the defense mechanisms of P. regnellii against M. spectabilis. The genotype with the fastest response to insect attack and highest nymph mortality (BGP 344) presented kinases and an enriched glutathione pathway, in addition to constitutive barriers, such as lignin, which can make it difficult for the insect to colonize the plant.

plant biology↗

bioRxiv2018

Apomixis-related genes identified from a coexpression network in Paspalum notatum, a Neotropical grass

Apomixis is a highly desirable trait in modern agriculture, due to the maintenance of characteristics of the mother plant in the progeny. However, incorporating it into breeding programs requires a deeper knowledge of its regulatory mechanisms. Paspalum notatum is considered a good model for such studies because it exhibits both sexual and apomictic cytotypes, facilitating the performance of comparative approaches. Therefore, we used comparative transcriptomics between contrasting P. notatum cytotypes to identify novel candidate genes involved in the regulation of the expression of this phenotype. We assembled and characterized a transcriptome from leaf and inflorescence from apomictic tetraploids and sexual diploids/tetraploids of P. notatum accessions, and then assembled a coexpression network based on pairwise correlation between transcripts expression profiles. We identified genes exclusively expressed in each cytotype and differentially expressed genes between pairs of cytotypes. Gene ontology enrichment analyses were performed for the interpretation of data. We de novo assembled 114,306 of reference transcripts. 536 novel candidate genes for the control of apomixis were detected through statistical analyses of expression data, contains in this set, the interactions among genes potentially linked to the apomixis-controlling region, differentially expressed, several genes also already reported in the literature and their neighbors transcriptionally related in the coexpression network. The reference transcriptome obtained in this study represents a robust set of expression data for P. notatum. Additionally, novel candidate genes identified in this work represent a valuable resource for future grass breeding programs.\n\nAuthor SummaryClonal mode of reproduction by seeds is termed apomixis, which results from the failure of gamete formation (meiosis) and fertilization in the sexual female reproductive pathway. The manipulation of seeds production genetically identical to the mother plant bears great promise for agricultural applications, however clarification regarding gene interactions involved in reproductive process is needed. Paspalum is considered a model genus for the analysis of apomixis mechanisms. Here, we describe an overall analysis of the expression profiles of Paspalum notatum transcripts in response to changes in reproductive mode (sexual to apomictic), which allowed us to identify several candidate apomixis genes. Among these, we found genes potentially associated with the apomixis control region, in addition to genes already described in the literature for Paspalum, which highlights the representativeness of assembled transcriptome. For the first time in the literature, we explored the main biological processes involved in controlling the expression of apomictic reproduction based on co-regulatory networks of candidate apomixis genes.

plant biology↗