Tao Xu

The genus Manglietia Blume is an important group of Magnoliaceae that has high economic and ornamental value. Owing to the small morphological differences among most Manglietia species and the limited sample sizes in previous molecular-level studies, its infrageneric classification remains unclear, and interspecific relationships for some species are still contentious. Clarifying the phylogenetic relationships within the genus Manglietia is crucial for species classification, genetic diversity assessment, and evolutionary developmental studies. This study sequenced, assembled, and annotated the chloroplast (cp) genomes of Manglietia guangnanica, Manglietia hookeri, and Manglietia longirostrata. The results indicated that these cp genomes are canonical quadripartite structures with total lengths of 160,067 bp, 160,067 bp, and 160,076 bp, respectively. All three cp genomes were annotated with 133 genes, comprising 88 protein-coding genes, 37 tRNAs, and 8 rRNAs. A total of 31, 30, and 30 dispersed repeats and 53, 53, and 56 SSRs were detected, respectively. ENC plot, neutrality plot, and PR2 plot analyses indicated that codon usage bias was influenced primarily by natural selection. Nucleotide diversity analysis revealed 8 highly variable regions in the cp genomes, among which petA-psbJ, rpl32-trnL, and ccsA-ndhD are recommended as candidate molecular markers for Manglietia species. Phylogenetic analysis revealed four highly supported clades: Clade I (18 species), Clade II (M. decidua only), Clade III (9 species), and Clade IV (M. caveana only). Among these clades, Clade IV is a newly discovered monotypic clade in this study, which differs from the results of all previous studies. Further investigations of Clades I and III, which include multiple Manglietia species, revealed that the presence or absence of hairs on Twigs, Stipules, and the abaxial surface of the leaf are important morphological characteristics for distinguishing species between these two clades. Furthermore, the results revealed that M. guangnanica and M. calcarea are two distinct species, and the treatment of M. longirostrata as a variety of M. hookeri was not supported by our study. This study enriches the cp genome data of Manglietia, provides new insights into infrageneric classification, and lays a foundation for further phylogenetic and evolutionary studies of Manglietia.

Schisandra macrocarpa Lin & Shui, 2011, belongs to the family Schisandraceae and was recently added to the List of National Key Protected Wild Plants in China. We report the complete chloroplast (cp) genome of S. macrocarpa using Illumina Nova-Seq 6000 platform. The results showed that the cp genome size of S. macrocarpa was 144,288 bp, which contained a small single-copy (SSC) region (17,862 bp), a large single-copy (LSC) region (93,332 bp), and a pair of inverted repeat (IR) regions (16,547 bp). The cp genome has 40% overall GC content. Annotated genes were 128 in all, including 83 protein-coding genes, eight rRNA genes, and 37 tRNA genes. The phylogenetic analysis showed that S. macrocarpa was closely related to S. propinqua subsp. sinensis. This work contributes to the conservation of this species and the evolutionary analysis of Schisandraceae.

Flower endophytic fungi play a major role in plant reproduction, stress resistance, and growth and development. However, little is known about how artificial cultivation affects the endophytic fungal community found in the tepals of rare horticultural plants. In this research, we used high-throughput sequencing technology combined with bioinformatics analysis to reveal the endophytic fungal community of tepals in Lirianthe delavayi and the effects of artificial cultivation on the community composition and function of these plants, using tepals of L. delavayi from wild habitat, cultivated campus habitat, and cultivated field habitat as research objects. The results showed that the variety of endophytic fungi in the tepals of L. delavayi was abundant, with a total of 907 Amplicon sequencing variants (ASVs) obtained from all the samples, which were further classified into 4 phyla, 23 classes, 51 orders, 97 families, 156 genera, and 214 species. We also found that artificial cultivation had a significant impact on the community composition of endophytic fungi. Although there was no significant difference at the phylum level, with Ascomycota and Basidiomycota being the main phyla, there were significant differences in dominant and unique genera. Artificial cultivation has led to the addition of new pathogenic fungal genera, such as Phaeosphaeria, Botryosphaeria, and Paraconiothyrium, increasing the risk of disease in L. delavayi. In addition, the abundance of the endophytic fungus Rhodotorula, which is typical in plant reproductive organs, decreased. Artificial cultivation also altered the metabolic pathways of endophytic fungi, decreasing their ability to resist pests and diseases and reducing their ability to reproduce. A comparison of endophytic fungi in tepals and leaves revealed significant differences in community composition and changes in the endophytic diversity caused by artificial cultivation. To summarize, our results indicate that endophytic fungi in the tepals of L. delavayi mainly consist of pathogenic and saprophytic fungi. Simultaneously, artificial cultivation introduces a great number of pathogenic fungi that alter the metabolic pathways associated with plant resistance to disease and pests, as well as reproduction, which can increase the risk of plant disease and reduce plant reproductive capacity. Our study provides an important reference for the conservation and breeding of rare horticultural plants.

Lirianthe delavayi has valuable ornamental and medicinal value, is an important economic tree, and has a long history of cultivation. As important regulatory molecules, miRNAs are involved in important physiological processes, such as the plant stress response, organ morphogenesis, hormone secretion, and signaling. In this study, based on miRNA sequencing analysis of wild and cultivated Lirianthe delavayi, we explored the differences in posttranscriptional regulation during the cultivation of Lirianthe delavayi from the aspect of miRNA molecular regulation. The results revealed the following: 1. A total of 365 miRNAs were sequenced and identified, and their first bases had obvious uracil (U) base preferences. Among them, 242 miRNAs were classified into 32 miRNA families; 2. Analysis of miRNA expression differences revealed that 39 miRNAs had significant expression differences between wild and cultivated populations; 3. Bioinformatics target gene prediction and target gene enrichment analysis of significantly differentially expressed miRNAs revealed that the target genes were significantly enriched in plant‒pathogen interactions, sphingolipid metabolism, defense responses, and ADP binding. 4. The plant‒pathogen interaction pathway involves seven differentially expressed miRNAs and 30 miRNA‒target gene regulatory pairs, which are involved mainly in pathogen signature molecule recognition and binding, signal transduction, and the regulation of disease resistance molecules or gene expression; Ath-MIR169g-p3_2ss7AG19GA, ath-MIR169g-p5_2ss7AG19GA, and ath-miR408-3p_L-3 are expressed only in wild population, and it is hypothesized that the domestication process from wild to cultivation species may be accompanied by the loss of disease resistance-related miRNAs. This study provides a reference for exploring the posttranscriptional-level regulatory mechanisms of adaptive changes in Lirianthe delavayi from wild to cultivated.

The genus Houpoea belongs to the family Magnoliaceae, and the species in this genus have important medicinal values. However, the investigation of the correlation between the evolution of the genus and its phylogeny has been severely hampered by the unknown range of species within the genus and the paucity of research on its chloroplast genome. Thus, we selected three species of Houpoea: Houpoea officinalis var officinalis (OO), Houpoea officinalis var. biloba (OB), and Houpoea rostrata (R). With lengths of 160,153 bp (OO), 160,011 bp (OB), and 160,070 bp (R), respectively, the whole chloroplast genomes (CPGs) of these three Houpoea plants were acquired via Illumina sequencing technology, and the findings were annotated and evaluated. These three chloroplast genomes were revealed by the annotation findings to be typical tetrads. A total of 131, 132, and 120 different genes were annotated. The CPGs of the three species had 52, 47, and 56 repeat sequences, which were primarily found in the ycf2 gene. A useful tool for identifying species is the approximately 170 simple sequence repeats (SSRs) that have been found. The border area of the reverse repetition region (IR) was studied, and it was shown that across the three Houpoea plants, it is highly conservative, with only changes between H. rostrata and the other two plants observed. Numerous highly variable areas (rps3-rps19, rpl32-trnL, ycf1, ccsA, etc.) have the potential to serve as the barcode label for Houpoea, according to an examination of mVISTA and nucleotide diversity (Pi). Phylogenetic relation indicates that Houpoea is a monophyletic taxon, and its genus range and systematic position are consistent with the Magnoliaceae system of Sima Yongkang-Lu Shugang, including five species and varieties of H. officinalis var. officinalis, H. rostrata, H. officinalis var. biloba, Houpoea obovate, and Houpoea tripetala, which evolved and differentiated from the ancestors of Houpoea to the present Houpoea in the above order. This study provides valuable information on the genus Houpoea, enriches the CPG information on Houpoea genus, and provides genetic resources for the further classification of and phylogenetic research on Houpoea.

Many wild ornamental plant species have been introduced to improve the landscape of cities; however, until now, no study has been performed to explore the composition and function of foliar endophytes associated with cultivated rare plants in cities after their introduction. In this study, we collected the leaves of the healthy ornamental plant Lirianthe delavayi from wild and artificially cultivated habitats in Yunnan and compared their diversity, species composition, and functional predictions of their foliar endophytic fungal community based on high-throughput sequencing technology. In total, 3125 ASVs of fungi were obtained. The alpha diversity indices of wild L. delavayi populations are similar to those of cultivated samples; however, the species compositions of endophytic fungal ASVs were significantly varied in the two habitats. The dominant phylum is Ascomycota, accounting for more than 90% of foliar endophytes in both populations; relatively, artificial cultivation trends to increase the frequency of common phytopathogens of L. delavayi, such as Alternaria, Erysiphe. The relative abundance of 55 functional predictions is different between wild and cultivated L. delavayi leaves (p < 0.05); in particular, chromosome, purine metabolism, and peptidases are significantly increased in wild samples, while flagellar assembly, bacterial chemotaxis, and fatty acid metabolism are significantly enhanced in cultivated samples. Our results indicated that artificial cultivation can greatly change the foliar endophytic fungal community of L. delavayi, which is valuable for understanding the influence of the domestication process on the foliar fungal community associated with rare ornamental plants in urban environments.

Manglietia longirostrata Sima is a rare and endemic species in China. The complete chloroplast genome (cpDNA) of M. longirostrata was sequenced and assembled in this study. The cpDNA is 160,049 bps in length, contains a large single-copy region (LSC) of 88,098 bp and a small single-copy region (SSC) of 18,861 bp, separated by a pair of identical inverted repeat (IR) regions of 26,571 bp, each. The genome contains 123 genes, including 73 protein-coding genes, 8 ribosomal RNA genes, and 37 transfer RNA genes. Phylogenetic analysis of cp genome of M. longirostrata with 11 chloroplast genomes previously reported in the Magnoliaceae shows that M. longirostrata is close to Manglietia megaphylla with high bootstrap value.

Magnolia delavayi is a rare, famous ornamental and important medical tree endemic to China. Here, we assembled the complete chloroplast (cp) genome sequence of M. delavayi. Its length is 159,715 bp with four sub-regions: 87,906 bp of large single-copy region and 18,761 bp of small single-copy region are separated by two inverted repeats regions, each 26,524 bp. The genome contains 77 protein-coding genes, 6 rRNAs, and 29 tRNAs genes. Phylogenetic analysis of cp genome of M. delavayi with previously reported chloroplast genomes in Magnolia shows that M. delavayi is close to M. odoratissima with high bootstrap value.