SSR marker based analysis for identification and of genetic diversity of non-heading Chinese cabbage varieties

Molecular identification of F1 hybrids of Fraxinus mandshurica × Fraxinus chinensis using SSR markers

To breed new Fraxinus varieties with superior traits including rapid growth, drought tolerance, and salinity resistance, this study established 480 F1 interspecific hybrid progeny through controlled pollination, using Fraxinus mandshurica Rupr. as the female parent and Fraxinus chinensis Roxb. as the male parent. Early-stage hybrid identification was performed using SSR (simple sequence repeat) markers. From 37 candidate SSR primers, two highly polymorphic pairs were selected for hybrid verification via polyacrylamide gel electrophoresis. Of the 480 offspring, 280 were confirmed as true hybrids, yielding a hybrid purity of 58.33 %. Primer pair Fm19 detected 62.29 % of hybrids, with partial overlap (shared detection) with primer pair Fc1. The polymorphism information content (PIC) ranged from 0.93 to 0.97 (mean: 0.95). Polymorphic alleles from both primers were converted into binary data (1 = present, 0 = absent) to generate unique molecular IDs for 144 hybrid offspring. This work established an efficient SSR-based method for early hybrid identification in F. mandshurica and F. chinensis, facilitating accelerated breeding and variety development.

Identification of Indigenous Thai Phlegmariurus Genotypic Population by Integrating Morphological and Molecular Studies

Phlegmariurus, a diverse genus within the Lycopodiaceae family, has wide diversity in tropical regions, including Thailand. Accurate species delimitation in the tropical clubmoss genus Phlegmariurus is challenged by high morphological plasticity and genetic complexity. This study applied an integrative multilocus approach combining morphometric analysis of 27 complete specimens, 35 Phlegmariurus and one Lycopodiella accessions for AFLP genotyping (926 loci; PIC 0.32), SSR profiling (44 loci; PIC 0.57; expected heterozygosity 0.35), and chloroplast barcoding using rbcL (1308 bp; bootstrap 89-99%) and the psbA-trnH intergenic spacer (308 bp; bootstrap ≥ 94%). A total of 13 were identified as belonging to seven known species, including P. nummulariifolius (NST01, NST15, NST36), P. goebelii (JP04), P. phlegmaria (NST13), P. verticillatus (PHI16), P. squarrosus (NST21, NST22, MY31), P. tetrastichus (NST30), and P. carinatus (MY32, MY33, NST34). Morphological clustering and molecular markers consistently distinguished Phlegmariurus accessions from the Lycopodiella outgroup. Additionally, 19 previously unclassified Phlegmariurus accessions were successfully identified as belonging to the species P. nummulariifolius (NST23), P. goebelii (NST03, JP05, STN12, PNA14, SKA25, CPN26, KRB27, PNA28), P. phlegmaria (NWT07, STN08, NST09, NST10, PHI29), P. squarrosus (NST17), and P. carinatus (PNA06, STN18, CPN19, JP24). Moreover, this study identified three novel lineages (NST02, STN11, NST20) with strong support across datasets. The combination of broad genomic coverage (AFLP), fine-scale allelic resolution (SSR), deep-branch backbone (rbcL), and terminal-branch discrimination (psbA-trnH) yields a robust framework for species identification. These results define clear operational units for conservation prioritization and establish a foundation for marker-assisted development of ornamental Phlegmariurus cultivars.

Genetic diversity evaluation and selection methods of sweet potato hybrid F1 population based on SSR markers and phenotypic detection

Sweet potato (Ipomoea batatas (L.) Lam.) is a vital global crop, with breeding focused on both high starch and high yield. Hybrid populations are crucial for genetic improvement, but research on sweet potato hybrid F1 populations remains limited. To explore the genetic laws of important traits in hybrid progenies, this study investigates the genetic diversity and efficient selection methods of the hybrid F1 population from crossing between Yushu No.12 (high starch content) and Luoxushu No.9 (high yield) using phenotypic detection and SSR markers. Coefficients of variation, genetic distances, and similarity coefficients results showed that the F1 population has rich genetic diversity. The parents and F1 progenies could be clustered into 4 and 6 categories based on phenotypic detection and SSR markers, respectively. The results of transgressive inheritance analysis and cluster analysis showed that the hybrid F1 population of sweet potato was closer to the female parent and might exhibit matroclinous inheritance. Based on the principal component analysis (PCA) results, a comprehensive scoring model was developed to select superior progeny. Correlation analysis revealed a strong link (r = 0.6420) between the hardness and starch content of storage root, suggesting hardness could be used for rapid screening high-starch materials. Mantel test showed SSR markers as more reliable for evaluating genetic diversity than phenotypic analysis. These findings uncover the genetic diversity information of sweet potato F1 generation, and provide strategies for the rapid and accurate selection of hybrid progenies, and lay theoretical foundation for deciphering the genetic mechanisms of important traits in sweet potato.

Comparative and phylogenetic analysis of Potentilla and Dasiphora (Rosaceae) based on plastid genome

BACKGROUND

Potentilla L. and Dasiphora L. are predominantly perennial herbs, occasionally manifesting as annuals or shrubs, primarily found in the northern temperate zone. However, taxonomic classification within this group remains contentious, particularly regarding genus boundaries and species delineation. Therefore, this study sequenced and analyzed the complete plastid genomes of 19 species from Potentilla and Dasiphora, comparing them with five previously published plastid sequences. Our objectives included reconstructing phylogenetic relationships within Potentilla and Dasiphora and investigating cytonuclear discordance among them.

RESULTS

These plastid genomes were highly conserved in structure, GC content, and overall genome composition, comprising 84 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Notably, all Dasiphora plastid genomes lacked the unique intron for rpl2. Comparative genomic analyses revealed that variations in plastid genome size were due to differences in the lengths of the LSC, SSC, and IR regions. The IR region was predominantly conserved, while non-coding regions exhibited higher variability than coding regions. We screened SSR and identified seven highly variable loci that serve as potential molecular markers, offering valuable insights into the intergeneric relationships between Potentilla and Dasiphora. Phylogenetic analyses based on nuclear (ITS, ETS) and cytoplasmic (plastid, mitochondrial) genes confirmed the monophyly of Potentilla and Dasiphora, with results largely consistent with previous studies and supported by robust reliability metrics. We identified cytonuclear conflicts within Potentilla, which frequently disrupt its monophyly. We hypothesize that these conflicts may result from interspecific hybridization or incomplete lineage sorting events during the evolutionary history of the genus.

CONCLUSIONS

This study offers a theoretical foundation for advancing molecular identification and phylogenetic research on Potentilla and Dasiphora species. However, future work could benefit from greater detail on the criteria for selecting mitochondrial gene sequences and nrDNA datasets.

Genome-wide development of simple sequence repeats markers and genetic diversity analysis of chayote

BACKGROUND

Chayote is a high economic crop in the Cucurbitaceae family, playing an important role in food production, disease treatment and the production of degradable materials in industries. Due to the harsh environment, such as high temperature, drought and frost, some chayote resources are gradually disappearing. It is crucial to collect, characterize, and conserve chayote resources. However, the genetic diversity of chayote resources in China has not been studied so far.

RESULTS

In this study, we collected 35 individuals of chayote from 14 provinces in China. Subsequently, we found 363,156 SSR motifs from the chayote genome and designed 57 pairs of SSR primers for validation. Out of these, 48 primer pairs successfully amplified bands, with 42 of them showing polymorphism. These 42 primer pairs detected a total of 153 alleles, averaging 3.64 alleles per locus. The polymorphic information content ranged from 0.03 to 0.78, with an average value of 0.41, indicating a high level of polymorphism. Based on the analysis using STRUCTURE, PCoA, and UPGMA methods, the 35 chayote individuals were divided into two major clusters. Through further association analysis, 7 significantly associated SSR markers were identified, including four related to peel color and three related to spine.

CONCLUSIONS

These molecular markers will contribute to the analysis of genetic diversity and genetic breeding improvement of chayote in the future.

Morphological variation and expressed sequence tags-simple sequence repeats-based genetic diversity of Aspergillus cristatus in Chinese dark tea

Introduction

Aspergillus cristatus is a homothallic fungus that is used in the natural fermentation process of Chinese Fuzhuan tea and has been linked to the production of bioactive components. However, not much is known about the variations present in the fungus. To understand the variation of the dominant microorganism, A. cristatus, within dark tea, the present study investigated the genetic and morphological diversity of 70 A. cristatus collected across six provinces of China.

Methods

Expressed sequence tags-simple sequence repeats (EST-SSR) loci for A. cristatus were identified and corresponding primers were developed. Subsequently, 15 specimens were selected for PCR amplification.

Results

The phylogenetic tree obtained revealed four distinct clusters with a genetic similarity coefficient of 0.983, corresponding to previously identified morphological groups. Five strains (A1, A11, B1, D1, and JH1805) with considerable differences in EST-SSR results were selected for further physiological variation investigation. Microstructural examinations revealed no apparent differentiation among the representative strains. However, colony morphology under a range of culture media varied substantially between strains, as did the extracellular enzymatic activity (cellulase, pectinase, protease, and polyphenol oxidase); the data indicate that there are differences in physiological metabolic capacity among A. cristatus strains.

Discussion

Notably, JH1805, B1, and A11 exhibited higher enzymatic activity, indicating their potential application in the production of genetically improved strains. The findings provide valuable insights into species identification, genetic diversity determination, and marker-assisted breeding strategies for A. cristatus.

Genome-Wide Identification of Proline Transporter Gene Family in Non-Heading Chinese Cabbage and Functional Analysis of BchProT1 under Heat Stress

Non-heading Chinese cabbage prefers cool temperatures, and heat stress has become a major factor for reduced yield. The proline transporter protein (ProT) is highly selective for proline transport, contributing to the heat tolerance of non-heading Chinese cabbage. However, there has been no systematic study on the identification and potential functions of the ProT gene family in response to heat stress in non-heading Chinese cabbage. We identified six BchProT genes containing 11-12 transmembrane helices characteristic of membrane proteins through whole-genome sequencing. These genes diverged into three evolutionary branches and exhibited similarity in motifs and intron/exon numbers. Segmental duplication is the primary driving force for the amplification of BchProT. Notably, many stress-related elements have been identified in the promoters of BchProT using cis-acting element analysis. The expression level of BchProT6 was the highest in petioles, and the expression level of BchProT1 was the highest under high-temperature stress. Subcellular localization indicated their function at cell membranes. Heterologous expression of BchProT1 in Arabidopsis plants increased proline transport synthesis under heat-stress conditions. This study provides valuable information for exploring the molecular mechanisms underlying heat tolerance mediated by members of the BchProT family.