BMC Plant Biology最新文献

In light of the detrimental effects of global warming, exacerbated by the intense sunlight and high temperatures prevalent during summer in southern China, on the growth of Melaleuca alternifolia (M. alternifolia) seedlings, this study sets out to examine the impact of various shading treatments on the growth and physiological attributes of M. alternifolia seedlings, with the aim of determining the optimum shading level. The seedling phase is of paramount importance in the growth cycle and regeneration process of M. alternifolia, as both excessive and insufficient light exposure can negatively influence seedling development. Four shading regimes (CK: no shading; C1: 35-45% shading; C2: 45-50% shading; C3: 60-70% shading) were imposed on M. alternifolia seedlings, following which observations were conducted after a 35-day period. The results reveal that the different shading treatments had a significant effect on the growth and physiological indicators of the seedlings, with the moderate shading treatment (C2) proving to be the most advantageous for seedling growth. Under the C2 treatment, an increase in chlorophyll content was observed in the leaves of the seedlings, accompanied by a decrease in malondialdehyde (MDA) content. Concurrently, there was a reduction in the activities of antioxidant enzymes, namely superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Furthermore, the levels of abscisic acid (ABA) and gibberellic acid (GA3) declined, while the concentrations of auxin (IAA), salicylic acid (SA), and cytokinin (CTK) ascended. Leaf anatomical analysis disclosed that, in comparison to the control group, the thickness of the lower epidermis and palisade tissue in the leaves of the seedlings subjected to the C2 treatment exhibited a significant reduction. Additionally, an increase in the number of spongy tissue cells was noted, along with a marked increase in total leaf thickness. Consequently, cultivating M. alternifolia seedlings under shading conditions ranging from 45 to 50% is deemed more favorable. The findings of this study offer novel insights into the adaptive responses of M. alternifolia seedlings to varying light intensities and provide theoretical guidance for the cultivation and management of M. alternifolia seedlings in the southern regions of China.

Background: The global prevalence of herbal-based health care rapidly promoted requirements for medicinal plant resources. Accurate classification and identification are crucial to assuring the safety of these herbal sources.

Results: Here, we took Dendrobium (Orchidaceae), a famous horticultural and medicinal plant taxon, as the study focus to establish an effective authentication approach for medicinal plants based on new mtDNA barcodes. We first de novo assembled three complete mitogenomes using Illumina and Nanopore data. These three mitogenomes were 635,454 bp-831,745 bp long with multichromosomal structures. Moreover, the three mitogenomes were compared to the other four published Dendrobium mitogenomes. The results revealed great variations of the structure and repeat contents among these mitogenomes, while gene contents and genomic sequences were relatively conserved. The analysis of mutational hotspots showed eight mitochondrial DNA regions with high sequence variability (> 5%) at the interspecific level, which could provide abundant informatic loci for phylogeny, genetic diversity, and identification analyses. We also newly obtained mitochondrial sequences of 45 individuals from 15 Dendrobium species for authentication analysis. These 15 Dendrobium species were successfully identified by the whole mitogenome sequences and the isoform combination (Mt17 + Mt19) respectively.

Conclusions: Our findings revealed that mitochondrial isoforms (chromosomes) could be used as super-barcodes for Dendrobium species authentication. The multi-chromosomal structure of mitogenomes provided new insights into the accurate authentication of medical plants.

Background: Epigallocatechin gallate (EGCG) imparts unique health benefits and flavour to tea. Photosynthesis plays a crucial role in modulating secondary metabolite production in plants, and this study investigated its impact on the biosynthesis of EGCG in tea plants under different ecological conditions.

Results: Enhanced photosynthetic activity and the increased EGCG content, total esterified catechins (TEC), total catechins (TC) responded synchronously to changes in ecological factors. The photosynthetic capacity of tea plants and the EGCG content fit surface model equations (Extreme 2D and Polynomial 2D) and multiple regression equations (R² > 70%). Additionally, logistic regression and ROC curves revealed that photosynthetic capacity was related to EGCG accumulation patterns in response to ecological variations. Upon perceiving ecological changes, the response of photosynthesis-related genes (CspsaA from photosystem I, CspsbB, CspsbC from photosystem II, and CsLHCB3 from the antenna protein pathway) was associated to carbon cycle-related genes (CsALDO, CsACOX, CsICDH, Csrbcs), which mediated the expression of CsPAL in the phenylalanine pathway; CsaroDE in the shikimate pathway; and CsCHS, CsF3H, CsF3'H, and CsANS in the flavonoid pathway. Eventually, this influenced the accumulation of EGCG and its precursors (gallic acid and epigallocatechin) in tea plants.

Conclusions: This study reveals the effects of photosynthesis on EGCG biosynthesis in response to ecological factors, providing insights for optimizing tea cultivation and quality.

Background: Arctium lappa L. is a medicinal edible homologous plant, commonly known as burdock or bardana, which belongs to the Asteraceae family and is abundant all over the world. Genetic diversity assessment is essential for A. lappa germplasm resource conservation and breeding. The assessment techniques include morphological, biochemical, and DNA marker analysis. However, the limited number of available DNA markers is insufficient to conduct related genetic diversity assessment studies.

Results: In this study, we conducted RNA sequencing of the A. lappa cultivar 'Yanagikawa Ideal' and developed SSR markers to characterize the genetic diversity and population structure of 56 A. lappa accessions and 8 wild relative accessions. A total of 4,851 simple sequence repeats (SSRs) loci were identified. The proportions of mono-, di- and tri-nucleotide repeat motifs were 30.40%, 21.50% and 33.10%, respectively. We developed and verified the reliability of 28 SSR core primer pairs through electronic polymerase chain reaction (ePCR) and the PCR amplification process. The polymorphism information content (PIC) values of the 28 SSR core primer pairs ranged from 0.246 to 0.848, with 14 pairs of SSR primers displaying high polymorphism (PIC > 0.5). The 28 SSR core primer pairs showed 100% mobility in Arctium tomentosum Miller and 96.43% mobility in Synurus deltoides (Aiton) Nakai, indicating their high versatility. The average Shannon information index (I) was 1.231, and the average observed heterozygosity (Ho) was 0.132, the average expected heterozygosity (He) was 0.564. The 64 accessions were divided into three clusters at a genetic distance of 0.558. AMOVA analysis shows 83% genetic variation within populations and 17% among populations, highlighting implications for conservation and breeding strategies.

Conclusion: Our study provides 28 newly high-quality SSR markers to enhance genetic resource conservation and breeding programs for A. lappa, as well as to support comparative genomics and cross-species breeding strategies for related species.

Background: Lipids in rapeseed is of great significance to human health, and 'Fangyou 777' (No. GPD-2019-510073) has been identified as an excellent cultivar with high oil content. However, the change of lipid profile at different ripening stages remain unclear. Herein, UPLC-MS/MS was utilized for comprehensive lipidomics analysis of 'Fangyou 777' and its parents at four ripening stages.

Results: 778 lipids components across 25 subclasses were identified, and triglycerides (TGs), diglycerides (DGs), phosphatidylserines (PSs), phosphatidylinositols (PIs), phosphatidylglycerols (PGs), phosphatidylcholines (PCs), phosphatidylethanolamines (PEs), and free fatty acids (FFAs) were identified as the dominant lipid subclass. Due to heterotic vigor, the total lipids, TGs, FFAs, lysophosphatidylglycerol (LPGs) and PSs contents in 'Fangyou 777' were significantly higher than its parents. The PCA and OPLS-DA results elucidated that lipids in 'Fangyou 777' differed obviously from its parents at S1 (17 April, 2023; 28 days before ripening, 28 DBR), S2 (1 May, 2023; 14 DBR), and S3 (15 May, 2023; ripening day). TG(18:1_18:3_22:1), TG(18:1_22:1_18:2), TG(16:0_18:1_20:1), TG(16:0_18:1_22:1), TG(20:1_18:2_20:2), TG(18:1_18:1_20:1), and FFA(24:4) were recognized as key differential lipids. The glycerolipid metabolism and unsaturated fatty acid biosynthesis were the differential metabolic pathways at S1 and S3, while glycosylphosphatidylinositol (GPI)-anchor biosynthesis and glycerophospholipid metabolism were the differential metabolic pathways at S2 and S4 (7 days after ripening/physiologically ripened for one week).

Conclusion: This study provided a comprehensive profile to facilitate the understanding lipids accumulation in 'Fangyou 777' and its parents during ripening stages, and offered a foundation to comprehend lipid metabolism.

Background: The tuberous roots of Potentilla anserina (Pan), which are called silverweed cinquefoil roots, serve as a source of starch for the inhabitants of the Qinghai-Tibet Plateau. They are also regarded as a valuable tonic food and herbal medicine in the ethnic medicine system. Starch plays a crucial part in the plant's life cycle, particularly during the growth stage and in response to abiotic stress. Moreover, numerous biological processes and regulatory networks are involved in the synthesis and accumulation of starch.

Results: In this research, a combination of transcriptome and metabolomics approaches were employed to analyze the genes related to starch synthesis and degradation in Pan. The crucial genes involved in starch metabolism were identified, and the response characteristics of these genes to drought and low temperature treatments were investigated. Seven AMYs (Alpha-amylases) and 18 BAMs (Beta-amylases) were identified from the genome of Pan. Molecular phylogenetic analyses of AMYs and BAMs derived from 11 species of rosids were conducted respectively. AMYs of Pan and other species were clustered into 3 groups, whereas BAMs were classified into 4 groups. In the tuberous roots, when compared with the control conditions, 2 AMYs and 4 BAMs were upregulated, while 3 BAMs were downregulated, meanwhile, the contents of maltose and glucose-6-phosphate (G6P) were decreased, while the content of glucose-1-phosphate (G1P) was increased under drought treatment. In the tuberous roots under low temperature treatment, 1 BAM was upregulated, while 2 AMYs and 4 BAMs were downregulated compared with control. The response characteristics of AMYs and BAMs to drought and low temperature treatments were further verified through qPCR analysis.

Conclusions: In this research, the genes associated with starch synthesis in Pan were characterized, and the functions of AMYs and BAMs in abiotic stress treatments were elucidated. An overview of evolution of AMY and BAM gene families within rosids was also provided.

Background: This study examines the effectiveness of arbuscular mycorrhizal fungi (AMF, Rhizophagus irregularis) as a bioprotection strategy to improve wheat's physiological and biochemical responses. This study utilized soil inoculation with AMF and plant-controlled infestation with aphids, conducted over four weeks with three replicates per treatment.

Results: Although aphid infestation reduced root colonization by 26.8% and hyphal length by 30.7%, with no effect on arbuscular numbers (p < 0.05), AMF treatment improved growth, physiology, and metabolism of AMF-treated plants, especially under aphid infestation. AMF-treated plants showed a 51% increase in fresh weight and a 38% improvement in photosynthetic rates under infestation, indicating enhanced photosynthetic efficiency compared to controls. At the metabolism level, AMF application, particularly in infested plants, increased the levels of several amino acids, such as asparagine and glutamine, which increased by 23% and 20%, respectively. AMF treatment significantly boosted nitrogen metabolism enzymes, with activity increasing up to 4.8-fold in infested plants and arginase activity rising by 49% in infested and 290% in non-infested conditions. This metabolic shift elevated antioxidant levels, increasing flavonoids by 40% and polyphenols by 95% under aphid infestation. Additionally, antimicrobial efficacy improved, with AMF-treated plant extracts showing 30-67% larger inhibition zones against pathogens like Staphylococcus epidermidis and Salmonella typhimurium than untreated plants (p < 0.05).

Conclusions: This research examined the potential of AMF as a sustainable pest management tool, specifically focusing on its ability to enhance crop health and boost defenses against biotic stress. The study further highlights how AMF treatment improves antimicrobial efficacy, which can be integrated into farming practices to maintain plant growth while offering distinct advantages over conventional pest management strategies.

Background: SWEET (Sugar Will Eventually be Exported Transporter) proteins play vital roles in the transport of sugars, contributing to the regulation of plant development, hormone signaling, and responses to abiotic stress.

Results: In this study, we identified 57 NtSWEETs in tobacco (Nicotiana tabacum L.), and then their physicochemical properties, chromosomal localization, synteny, phylogenetic relationships, genomic structure, promoter cis-elements, protein interaction network, tissue specificity, and expression pattern were systematically analyzed. In addition, NtSWEET12i improves drought and saline-alkali tolerance in tobacco by enhancing soluble sugars transport, ABA signaling, proline biosynthesis, and ROS scavenging. These findings illuminate the role of NtSWEETs, particularly NtSWEET12i, in regulating plant tolerance to drought and saline-alkali stresses.

Conclusions: This study offers new insights to enhance our understanding of the roles of NtSWEETs and identify potential genes involved in drought and saline-alkali tolerance of plants.

Clinical trial number: Not applicable.

Background: The levels of free amino acids (FAAs) and the timing of bud flush (TBF) are among the the most economic traits of tea plants (Camellia sinensis). Investigating the genetic variation characteristics of FAAs and their potential associations with TBF is critical for the breeding of new tea cultivars with high economic value.

Methods: In this study, we utilized the 'Emei Wenchun' (♀) × 'Chuanmu 217' (♂) filial 1 (F₁) genetic population (n = 208) and measured their FAA contents in the "one bud and two leaves" samples across two spring seasons and one summer season using high-performance liquid chromatography combined with the Waters AccQ-Tag method. The sprouting index (SPI) was observed over two springs to quantify the TBF trait. A genetic map previously constructed based on the same population was employed for quantitative trait loci (QTL) mapping.

Results: A total of 16 FAAs were measured, and the average total FAA contents were 28.1 and 25.4 mg/g (dry weight) in the two spring seasons and 14.29 mg/g in the summer season. Within the population, the coefficients of variation (CV) for the FAAs ranged from 23 to 41% within each season, and the correlation coefficients (r) varied from 0.15 to 0.35 across seasons. ANOVA analyses revealed that 13 out of the 16 FAAs exhibited significant genetic variation, with the estimated broad-sense heritability (h²) ranging between 10.33% and 57.10%. Interestingly, three FAAs and the total FAA contents showed significant positive correlations (r = 0.21-0.34, P < 0.01) with the SPI trait in both spring seasons. QTL mapping identified 13 FAA-associated QTLs distributed across eight linkage groups.

Conclusion: Within the F₁ population, the FAAs exhibited considerable variation across seasons, their heritabilities were generally low (most ≤ 50%). There was a weak but significant positive correlation between FAAs and TBF. Additionally, 13 FAA-associated QTLs were identified. The results of this study enhance our understanding of the genetic variation characteristics of FAAs and provide insights for breeding tea cultivars with both higher FAAs and earlier TBF.