Population genomics analysis reveals footprints of selective breeding in a rapid-growth variety of Paulownia fortunei with apical dominance.

Paulownia fortunei is an ecologically and economically valuable tree cultivated for its rapid growth and high-quality timber. To enhance Paulownia germplasm, we have developed the elite variety QingT with patented advantages in growth rate and apical dominance. To illuminate the genetic basis of QingT's superior traits, here we harness comparative population genomics to analyze genomic variation patterns between QingT and common Paulownia. We performed whole-genome re-sequencing of 30 QingT and 30 common samples, detecting 15.6 million SNPs and 2.6 million indels. Phylogeny and population structure analyses robustly partitioned common and QingT into distinct groups which indicate robust genome stabilization. QingT exhibited reduced heterozygosity and linkage disequilibrium decay compared to common Paulownia, reflecting high recombination, indicating hybridizing effects with common white-flowered string is the source of its patented advantages. Genome selection scans uncovered 25 regions of 169 genes with elevated nucleotide diversity, indicating selection sweeps among groups. Functional analysis of sweep genes revealed upregulation of ribosomal, biosynthesis, and growth pathways in QingT, implicating enhanced protein production and developmental processes in its rapid growth phenotype. This study's insights comprehensively chart genomic variation during Paulownia breeding, localizing candidate loci governing agronomic traits, and underpinnings of future molecular breeding efforts to boost productivity.

Reassessment of the Phylogenetics of Two Pygmy Grasshopper Generic Groups Tetrix and Systolederus through Mitochondrial Phylogenomics Using Four New Mitochondrial Genome Assemblies.

Mitochondrial genomes offer pragmatic genetic markers to reconstruct evolutionary relationships and inform taxonomic classifications. Here, we present complete mitochondrial sequences for four Chinese pygmy grasshoppers (Tetrigidae), aiming to reevaluate phylogenetic patterns and morphological taxonomy. Our 17,643 bp, 16,274 bp, 15,086 bp, and 15,398 bp mitogenomes of Exothotettix guangxiensis, Formosatettix longwangshanensis, Euparatettix sinufemoralis and Systolederus zhengi, respectively, exhibit archetypal Tetrigidae architecture. We constructed phylogenies using 13 protein-coding loci from 39 Tetrigidae mitogenomes, revealing several genus-level clusters with statistically solid support, conflicts regarding Ex. guangxiensis, F. longwangshanensis merging into Tetrix, and two subclades of Systolederus. The dated divergence analysis indicates over 150 Mya of Tetrigidae ancestry, tracing the Systolederus generic group splits up to ~75 million years ago. Moreover, the Tetrix generic group radiated over 14 Mya across vast distributions, consistent with rapid adaptive dispersals. Our mitochondrial reconstructions suggest that Synstolederus is taxonomically overextended for a single genus, while the distinctiveness of Ex. guangxiensis and F. longwangshanensis from Tetrix appears questionable, and the Tetrix generic group comprises a potential tRNA-Ile coding region. Our integrative mitogenomic approaches will help resolve issues stemming from morphological taxonomy that is reliant on traits that are prone to convergence. This investigation enhances comprehension of Tetrigidae phylogeny and accentuates molecular systematics.

Chromosomal-Level Reference Genome for the Chinese Endemic Pygmy Grasshopper, Zhengitettix transpicula, Sheds Light on Tetrigidae Evolution and Advancing Conservation Efforts.

The pygmy grasshopper, Zhengitettix transpicula, is a Chinese endemic species with an exceedingly limited distribution and fragile population structure, rendering it vulnerable to extinction. We present a high-continuity, chromosome-scale reference genome assembly to elucidate this species' distinctive biology and inform conservation. Employing an integrated sequencing approach, we achieved a 970.40 Mb assembly with 96.32% coverage across seven pseudo-chromosomes and impressive continuity (N50 > 220 Mb). Genome annotation achieves identification with 99.2% BUSCO completeness, supporting quality. Comparative analyses with 14 genomes from Orthoptera-facilitated phylogenomics and revealed 549 significantly expanded gene families in Z. transpicula associated with metabolism, stress response, and development. However, genomic analysis exposed remarkably low heterozygosity (0.02%), implying a severe genetic bottleneck from small, fragmented populations, characteristic of species vulnerable to extinction from environmental disruptions. Elucidating the genetic basis of population dynamics and specialization provides an imperative guideline for habitat conservation and restoration of this rare organism. Moreover, divergent evolution analysis of the CYP305m2 gene regulating locust aggregation highlighted potential structural and hence functional variations between Acrididae and Tetrigidae. Our chromosomal genomic characterization of Z. transpicula advances Orthopteran resources, establishing a framework for evolutionary developmental explorations and applied conservation genomics, reversing the trajectory of this unique grasshopper lineage towards oblivion.

A high-quality chromosome-level genome assembly of the endangered tree Kmeria septentrionalis.

Kmeria septentrionalis is a critically endangered tree endemic to Guangxi, China, and is listed on the International Union for Conservation of Nature's Red List. The lack of genetic information and high-quality genome data has hindered conservation efforts and studies on this species. In this study, we present a chromosome-level genome assembly of K. septentrionalis. The genome was initially assembled to be 2.57 Gb, with a contig N50 of 11.93 Mb. Hi-C guided genome assembly allowed us to anchor 98.83% of the total length of the initial contigs onto 19 pseudochromosomes, resulting in a scaffold N50 of 135.08 Mb. The final chromosome-level genome, spaning 2.54 Gb, achieved a BUSCO completeness of 98.9% and contained 1.67 Gb repetitive elements and 35,927 coding genes. This high-quality genome assembly provides a valuable resource for understanding the genetic basis of conservation-related traits and biological properties of this endangered tree species. Furthermore, it lays a critical foundation for evolutionary studies within the Magnoliaceae family.