Identification of RAPD markers, in situ DNA content and structural chromosomal diversity in some legumes of the mangrove flora of Orissa

Patterns of chromosomal variation in Mexican species of Aeschynomene (Fabaceae, Papilionoideae) and their evolutionary and taxonomic implications

A cytogenetic analysis of sixteen taxa of the genus Aeschynomene Linnaeus, 1753, which includes species belonging to both subgenera Aeschynomene (Léonard, 1954) and Ochopodium (Vogel, 1838) J. Léonard, 1954, was performed. All studied species had the same chromosome number (2n = 20) but exhibited karyotype diversity originating in different combinations of metacentric, submetacentric and subtelocentric chromosomes, chromosome size and number of SAT chromosomes. The plasticity of the genomes included the observation in a taxon belonging to the subgenus Aeschynomene of an isolated spherical structure similar in appearance to the extra chromosomal circular DNA observed in other plant genera. By superimposing the karyotypes in a recent phylogenetic tree, a correspondence between morphology, phylogeny and cytogenetic characteristics of the taxa included in the subgenus Aeschynomene is observed. Unlike subgenus Aeschynomene, the species of Ochopodium exhibit notable karyotype heterogeneity. However the limited cytogenetic information recorded prevents us from supporting the proposal of their taxonomic separation and raise it to the genus category. It is shown that karyotype information is useful in the taxonomic delimitation of Aeschynomene and that the diversity in the diploid level preceded the hybridization/polyploidization demonstrated in the genus. The systematic implications of our results and their value can be extended to other Dalbergieae genera as knowledge about the chromosomal structure and its evolution increases.

LegumeDB: Development of Legume Medicinal Plant Database and Comparative Molecular Evolutionary Analysis of matK Proteins of Legumes and Mangroves

Background:

Legume plants are known for their rich medicinal and nutritional values. Large amount of medicinal information of various legume plants have been dispersed in the form of text.

Objective:

It is essential to design and construct a legume medicinal plants database, which integrate respective classes of legumes and include knowledge regarding medicinal applications along with their protein/enzyme sequences.

Methods:

The design and development of Legume Medicinal Plants Database (LegumeDB) has been done by using Microsoft Structure Query Language Server 2017. DBMS was used as back end and ASP.Net was used to lay out front end operations. VB.Net was used as arranged program for coding. Multiple sequence alignment, phylogenetic analysis and homology modeling techniques were also used.

Results:

This database includes information of 50 Legume medicinal species, which might be helpful to explore the information for researchers. Further, maturase K (matK) protein sequences of legumes and mangroves were retrieved from NCBI for multiple sequence alignment and phylogenetic analysis to understand evolutionary lineage between legumes and mangroves. Homology modeling technique was used to determine three-dimensional structure of matK from Legume species i.e. Vigna unguiculata using matK of mangrove species, Thespesia populnea as a template. The matK sequence analysis results indicate the conserved residues among legume and mangrove species.

Conclusion:

Phylogenetic analysis revealed closeness between legume species Vigna unguiculata and mangrove species Thespesia populnea to each other, indicating their similarity and origin from common ancestor. Thus, these studies might be helpful to understand evolutionary relationship between legumes and mangroves.

:

LegumeDB availability: http://legumedatabase.co.in

Karyotype diversity and 2C DNA content in species of the Caesalpinia group

BACKGROUND

The Leguminosae family is the third-largest family of angiosperms, and Caesalpinioideae is its second-largest subfamily. A great number of species (approximately 205) are found in the Caesalpinia group within this subfamily; together with these species' phenotypic plasticity and the similarities in their morphological descriptors, make this a complex group for taxonomic and phylogenetic studies. The objective of the present work was to evaluate the karyotypic diversity and the 2C DNA content variation in 10 species of the Caesalpinia group, representing six genera: Paubrasilia, Caesalpinia, Cenostigma, Poincianella, Erythrostemon and Libidibia. The GC-rich heterochromatin and 45S rDNA sites (which are used as chromosome markers) were located to evaluate the karyotype diversity in the clade. The variation in the 2C DNA content was determined through flow cytometry.

RESULTS

The fluorochrome banding indicated that the chromomycin A₃⁺/4',6-diamidino-2-phenylindole^- blocks were exclusively in the terminal regions of the chromosomes, coinciding with 45S rDNA sites in all analyzed species. Physical mapping of the species (through fluorescence in situ hybridization) revealed variation in the size of the hybridization signals and in the number and distribution of the 45S rDNA sites. All hybridization sites were in the terminal regions of the chromosomes. In addition, all species had a hybridization site in the fourth chromosome pair. The 2C DNA content ranged from 1.54 pg in Erythrostemon calycina to 2.82 pg in the Paubrasilia echinata large-leaf variant. The Pa. echinata small-leaf variant was isolated from the other leaf variants through Scoot-Knott clustering.

CONCLUSIONS

The chromosome diversity and the variation in the 2C DNA content reinforce that the actual taxonomy and clustering of the analyzed taxa requires more genera that were previously proposed. This fact indicates that taxonomy, phylogeny and cytoevolutionary inference related to the complex Caesalpinia group have to be done through integrative evaluation.

Large-scale resource development in Gossypium hirsutum L. by 454 sequencing of genic-enriched libraries from six diverse genotypes

The sequence information has been proved to be an essential genomic resource in case of crop plants for their genetic improvement and better utilization by humans. To dissect the Gossypium hirsutum genome for large-scale development of genomic resources, we adopted hypomethylated restriction-based genomic enrichment strategy to sequence six diverse genotypes. Approximately 5.2-Gb data (more than 18.36 million reads) was generated which, after assembly, represents nearly 1.27-Gb genomic sequences. We predicted a total of 93,363 gene models (21,399 full length) and identified 35,923 gene models which were validated against already sequenced plant genomes. A total of 1,093 transcription factor-encoding genes, 3,135 promoter sequences and 78 miRNA (including 17 newly identified in Gossypium) were predicted. We identified significant no. of molecular markers including 47,093 novel simple sequence repeats and 66,364 novel single nucleotide polymorphisms. In addition, we developed NBRI-Comprehensive Cotton Genomics database, a web resource to provide access of cotton-related genomic resources developed at NBRI. This study contributes considerable amount of genomic resources and suggests a potential role of genic-enriched sequencing in genomic resource development for orphan crop plants.

Development and characterization of genomic and expressed SSRs for levant cotton (Gossypium herbaceum L.)

Four microsatellite-enriched genomic libraries for CA(15), GA(15), AAG(8) and ATG(8) repeats and transcriptome sequences of five cDNA libraries of Gossypium herbaceum were explored to develop simple sequence repeat (SSR) markers. A total of 428 unique clones from repeat enriched genomic libraries were mined for 584 genomic SSRs (gSSRs). In addition, 99,780 unigenes from transcriptome sequencing were explored for 8,900 SSR containing sequences with 12,471 expressed SSRs. The present study adds 1,970 expressed SSRs and 263 gSSRs to the public domain for the use of genetic studies of cotton. When 150 gSSRs and 50 expressed SSRs were tested on a panel of four species of cotton, 68 gSSRs and 12 expressed SSRs revealed polymorphism. These 200 SSRs were further deployed on 15 genotypes of levant cotton for the genetic diversity assessment. This is the first report on the successful use of repeat enriched genomic library and expressed sequence database for microsatellite markers development in G. herbaceum.