Biology subjects

Kharabian Masouleh, A.

Publications and source records attributed to Kharabian Masouleh, A..

4 recordsLinked to original sources

bioRxiv2023

Determination of phylogenetic relationships in the genus Mangifera based on whole chloroplast genome and nuclear genome sequences

The genus Mangifera (Anacardiaceae) includes 69 species of which Mangifera indica L. is the most important and primarily cultivated species for commercial mango production. Although the species are classified based on morphological descriptors, molecular evidence has proposed the hybrid origin of two species suggesting the possibility that more of the species may be of hybrid origin. To analyze evolutionary relationships within the genus, 13 samples representing 11 Mangifera species were sequenced and whole chloroplast (Cp) genomes and 47 common single-copy nuclear gene sequences were assembled and used for phylogenetic analysis using concatenation and coalescence-based methods. The Cp genome size varied from 151,752 to 158,965 bp with M. caesia and M. laurina having the smallest and largest genomes, respectively. Genome annotation revealed 80 protein-coding genes, 31 tRNA and four rRNA genes across all the species. Comparative analysis of whole Cp genome sequence and nuclear gene-based phylogenies revealed topological conflicts suggesting chloroplast capture or cross hybridization. The Cp genomes of M. altissima, M. applanata, M. caloneura and M. lalijiwa were similar to those of M. indica (99.9% sequence similarity). Their close sequence relationship suggests a common ancestry and likely cross-hybridization between wild relatives and M. indica. This study provides improved knowledge of phylogenetic relationships in Mangifera, indicating extensive gene flow among the different species, suggesting that hybrids may be common within the genus.

plant biology↗

bioRxiv2022

Haplotype resolved chromosome level genome assembly of Citrus australis reveals disease resistance and other citrus specific genes

Recent advances in genome sequencing and assembly techniques have made it possible to achieve chromosome level reference genomes for citrus. Relatively few genomes have been anchored at the chromosome level and/or are haplotype phased, with the available genomes of varying accuracy and completeness. We now report a phased high-quality chromosome level genome assembly for an Australian native citrus species; Citrus australis (round lime) using highly accurate PacBio HiFi long reads, complemented with Hi-C scaffolding. Hifiasm with Hi-C integrated assembly resulted in a 331 Mb genome of C. australis with two haplotypes of nine pseudochromosomes with an N50 of 36.3 Mb and 98.8% genome assembly completeness (BUSCO). Repeat analysis showed that more than 50% of the genome contained interspersed repeats. Among them, LTR elements were the predominant type (21.0%), of which LTR Gypsy (9.8 %) and LTR copia (7.7 %) elements were the most abundant repeats. A total of 29,464 genes and 32,009 transcripts were identified in the genome. Of these, 28,222 CDS (25,753 genes) had BLAST hits and 21,401 CDS (75.8%) were annotated with at least one GO term. Citrus specific genes for antimicrobial peptides, defense, volatile compounds and acidity regulation were identified. This chromosome scale, and haplotype resolved C. australis genome will facilitate the study of important genes for citrus breeding and will also allow the enhanced definition of the evolutionary relationships between wild and domesticated citrus species.

plant biology↗

bioRxiv2021

De-novo chromosome level assembly of plant genomes from long read sequence data

Recent advances in the sequencing and assembly of plant genomes have allowed the generation of genomes with increasing contiguity and sequence accuracy. The chromosome level assembly of the contigs generated from long read sequencing has involved the use of proximity analysis (Hi-C) or traditional genetic maps to guide the placement of sequence contigs within chromosomes. The development of highly accurate long reads by repeated sequencing of circularized DNA (PacBio HiFi) has greatly increased the size of contigs. We now report the use of HiFiasm to assemble the genome of Macadamia jansenii. a genome that has been used as model to test sequencing and assembly. This achieved almost complete chromosome level assembly from the sequence data alone without the need for higher level chromosome map information. Eight of the 14 chromosomes were represented by a single large contig and the other 6 assembled into 2-4 main contigs. The small number of chromosome breaks appear to be due to highly repetitive regions of ribosomal genes that cannot be assembled by these approaches. De novo assembly of near complete chromosome level plant genomes now seems possible using these sequencing and assembly tools. Further targeted strategies might allow these remaining gaps to be closed. Significance statement (of up to two sentences)De novo assembly of near complete chromosome level plant genomes is now possible using current long read sequencing and assembly tools.

genomics↗

bioRxiv2021

The genome of the endangered Macadamia jansenii displays little diversity but represents an 1 important genetic resource for plant breeding

Macadamia, a recently domesticated expanding nut crop in the tropical and subtropical regions of the world, is one of the most economically important genera in the diverse and widely adapted Proteaceae family. All four species of Macadamia are rare in the wild with the most recently discovered, M. jansenii, being endangered. The M. jansenii genome has been used as a model for testing sequencing methods using a wide range of long read sequencing techniques. Here we report a chromosome level genome assembly, generated using a combination of Pacific Biosciences sequencing and Hi-C, comprising 14 pseudo-molecules, with a N50 of 58 Mb and a total 758 Mb genome assembly size of which 56% is repetitive. Completeness assessment revealed that the assembly covered 96.9% of the conserved single copy genes. Annotation predicted 31,591 protein coding genes and allowed the characterization of genes encoding biosynthesis of cyanogenic glycosides, fatty acid metabolism and anti-microbial proteins. Re-sequencing of seven other genotypes confirmed low diversity and low heterozygosity within this endangered species. Important morphological characteristics of this species such as small tree size and high kernel recovery suggest that M. jansenii is an important source of these commercial traits for breeding. As a member of a small group of families that are sister to the core eudicots, this high-quality genome also provides a key resource for evolutionary and comparative genomics studies.

genomics↗