Unveiling the molecular dynamics of low temperature preservation in postharvest lotus seeds: a transcriptomic perspective.

BACKGROUND: Postharvest quality deterioration poses a significant challenge to the commercial value of fresh lotus seeds. Low temperature storage is widely employed as the primary method for preserving postharvest lotus seeds during storage and transportation. RESULTS: This approach effectively extends the storage life of lotus seeds, resulting in distinct physiological changes compared to room temperature storage, including a notable reduction in starch, protein, H2O2, and MDA content. Here, we conducted RNA-sequencing to generate global transcriptome profiles of postharvest lotus seeds stored under room or low temperature conditions. Principal component analysis (PCA) revealed that gene expression in postharvest lotus seeds demonstrated less variability during low temperature storage in comparison to room temperature storage. A total of 14,547 differentially expressed genes (DEGs) associated with various biological processes such as starch and sucrose metabolism, energy metabolism, and plant hormone signaling response were identified. Notably, the expression levels of DEGs involved in ABA signaling were significantly suppressed in contrast to room temperature storage. Additionally, nine weighted gene co-expression network analysis (WGCNA)-based gene molecular modules were identified, providing insights into the co-expression relationship of genes during postharvest storage. CONCLUSION: Our findings illuminate transcriptional differences in postharvest lotus seeds between room and low temperature storage, offering crucial insights into the molecular mechanisms of low temperature preservation in lotus seeds.

The miR6445-NAC029 module regulates drought tolerance by regulating the expression of glutathione S-transferase U23 and reactive oxygen species scavenging in Populus.

MicroRNAs are essential in plant development and stress resistance, but their specific roles in drought stress require further investigation. Here, we have uncovered that a Populus-specific microRNAs (miRNA), miR6445, targeting NAC (NAM, ATAF, and CUC) family genes, is involved in regulating drought tolerance of poplar. The expression level of miR6445 was significantly upregulated under drought stress; concomitantly, seven targeted NAC genes showed significant downregulation. Silencing the expression of miR6445 by short tandem target mimic technology significantly decreased the drought tolerance in poplar. Furthermore, 5' RACE experiments confirmed that miR6445 directly targeted NAC029. The overexpression lines of PtrNAC029 (OE-NAC029) showed increased sensitivity to drought compared with knockout lines (Crispr-NAC029), consistent with the drought-sensitive phenotype observed in miR6445-silenced strains. PtrNAC029 was further verified to directly bind to the promoters of glutathione S-transferase U23 (GSTU23) and inhibit its expression. Both Crispr-NAC029 and PtrGSTU23 overexpressing plants showed higher levels of PtrGSTU23 transcript and GST activity while accumulating less reactive oxygen species (ROS). Moreover, poplars overexpressing GSTU23 demonstrated enhanced drought tolerance. Taken together, our research reveals the crucial role of the miR6445-NAC029-GSTU23 module in enhancing poplar drought tolerance by regulating ROS homeostasis. This finding provides new molecular targets for improving the drought resistance of trees.

Aspartyl tRNA-synthetase (AspRS) gene family enhances drought tolerance in poplar through BABA-PtrIBIs-PtrVOZ signaling module.

BACKGROUND: Drought stress is a prevalent abiotic stress that significantly hinders the growth and development of plants. According to studies, ß-aminobutyric acid (BABA) can influence the ABA pathway through the AtIBI1 receptor gene to enhance cold resistance in Arabidopsis. However, the Aspartate tRNA-synthetase (AspRS) gene family, which acts as the receptor for BABA, has not yet been investigated in poplar. Particularly, it is uncertain how the AspRS gene family (PtrIBIs)r can resist drought stress after administering various concentrations of BABA to poplar. RESULTS: In this study, we have identified 12 AspRS family genes and noted that poplar acquired four PtrIBI pairs through whole genome duplication (WGD). We conducted cis-action element analysis and found a significant number of stress-related action elements on different PtrIBI genes promoters. The expression of most PtrIBI genes was up-regulated under beetle and mechanical damage stresses, indicating their potential role in responding to leaf damage stress. Our results suggest that a 50 mM BABA treatment can alleviate the damage caused by drought stress in plants. Additionally, via transcriptome sequencing, we observed that the partial up-regulation of BABA receptor genes, PtrIBI2/4/6/8/11, in poplars after drought treatment. We hypothesize that poplar responds to drought stress through the BABA-PtrIBIs-PtrVOZ coordinated ABA signaling pathway. Our research provides molecular evidence for understanding how plants respond to drought stress through external application of BABA. CONCLUSIONS: In summary, our study conducted genome-wide analysis of the AspRS family of P. trichocarpa and identified 12 PtrIBI genes. We utilized genomics and bioinformatics to determine various characteristics of PtrIBIs such as chromosomal localization, evolutionary tree, gene structure, gene doubling, promoter cis-elements, and expression profiles. Our study found that certain PtrIBI genes are regulated by drought, beetle, and mechanical damage implying their crucial role in enhancing poplar stress tolerance. Additionally, we observed that external application of low concentrations of BABA increased plant drought resistance under drought stress. Through the BABA-PtrIBIs-PtrVOZ signaling module, poplar plants were able to transduce ABA signaling and regulate their response to drought stress. These results suggest that the PtrIBI genes in poplar have the potential to improve drought tolerance in plants through the topical application of low concentrations of BABA.

Risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis patients.

OBJECTIVE: To investigate the risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis (MHD) patients. METHOD: We retrospectively collected data from 363 hemodialysis patients who were on dialysis for at least 3 months at January 1, 2020. According to the echocardiogram results, these patients were divided into left ventricular diastolic dysfunction (LVDD) group and non-LVDD group. The differences in basic data, cardiac structure and functiona between the two groups were analyzed. Logistic regression analysis was used to analyze the risk factors of cardiac diastolic dysfunction in MHD patients. RESULTS: Compared with the non-LVDD group, patients in the LVDD group were older, with an increased proportion of coronary heart disease, more prone to chest tightness, shortness of breath. Simultaneously, they had a significantly increased (p < 0.05) proportion of cardiac structural abnormalities such as left ventricular hypertrophy, left heart enlargement and systolic dysfunction. Multivariate logistic regression analysis showed that the risk of LVDD was significantly increased in elderly MHD patients older than 60 years (OR = 3.86, 95%CI 1.429-10.429), and left ventricular hypertrophy was also significantly associated with LVDD (OR = 2.227, 95% CI 1.383-3.586). CONCLUSION: According to research, both age and left ventricular hypertrophy are risk factors for LVDD in MHD patients. It is recommended that early intervention for LVDD should be implemented to improve the quality of dialysis and reduce the incidence of cardiovascular events in MHD patients.

Occurrence, Characteristics, and qPCR-Based Identification of Pectobacterium versatile Causing Soft Rot of Chinese Cabbage in China.

Pectobacterium is one of the most important genera of phytopathogenic bacteria. It can cause soft-rot diseases on a wide range of plant species across the world. In this study, three Pectobacterium strains (KC01, KC02, and KC03) were isolated from soft-rotted Chinese cabbage in Beijing, China. These three strains were identified as Pectobacterium versatile based on phylogenetic analysis of Pectobacterium 16S ribosomal RNA, pmrA, and 504 Pectobacterium core genes, as well as a genomic average nucleotide identity analysis. Their biochemical characteristics were found to be similar to the P. versatile type strain ICMP9168T but differed in response to citric acid, stachyose, D-glucuronic acid, dextrin, and N-acetyl-ß-D-mannosamine. All of the tested P. versatile strains showed different carbohydrate utilization abilities compared with P. carotovorum and P. odoriferum, particularly in their ability to utilize D-arabitol, L-rhamnose, and L-serine. Under laboratory conditions, the maceration ability of P. versatile on Chinese cabbage was the highest at 28°C, compared with those at 13, 28, 23, and 33°C. Additionally, P. versatile could infect all of the 17 known Pectobacterium host plants, except for Welsh onion (Allium fistulosum). A SYBR Green quantitative PCR (qPCR) detection system was developed to distinguish P. versatile from other soft-rot bacteria based on the combined performance of melting curve (with a single melting peak at around 85°C) and fluorescence curve (with cycle threshold <30) when the bacterial genomic DNA concentration was in the range of 10 pg/µl to 10 ng/µl. This study is the first to report the presence of P. versatile on Chinese cabbage in China, as well as a specific and sensitive qPCR assay that can be used to quickly identify P. versatile. The work contributes to a better understanding of P. versatile and will facilitate the effective diagnosis of soft-rot disease, ultimately benefitting commercial crop production.

Investigation of the Role of a Zinc Uptake Regulator (Zur) in the Virulence of Pectobacterium odoriferum.

Pectobacterium spp. infect many horticultural crops worldwide and lead to serious crop losses. Zinc-uptake-regulator (Zur) proteins are present widely in prokaryotes and play an important role in pathogenicity. To uncover the role of Zur in P. odoriferum, we constructed mutant (ΔZur) and overexpression [Po (Zur)] strains of a Zur, and a virulence assay showed that the Po (Zur) was of significantly lower virulence, while the ΔZur displayed significantly increased virulence on Chinese cabbage compared to their respective control strains, wild-type P. odoriferum (Po WT) and P. odoriferum harboring an empty vector (Po (EV)) (p < 0.05). The growth curves of the ΔZur and Po (Zur) showed no obvious differences from those of the control strains. Comparative transcriptome analysis showed that Zur overexpression in P. odoriferum induced differentially expressed genes (DEGs) related to flagellum and cell motility, while mutating Zur resulted in DEGs mainly corresponding to divalent-metal-ion transport and membrane transport. Phenotypic experiments on the Po (Zur) showed that flagellum numbers and cell motility were reduced in comparison with the control, while those of the ΔZur did not change. Collectively, these results show that the Zur negatively regulates the virulence of P. odoriferum and might function via a dual mechanism dependent on dose.

Genome-Wide Analysis of the FBA Subfamily of the Poplar F-Box Gene Family and Its Role under Drought Stress.

F-box proteins are important components of eukaryotic SCF E3 ubiquitin ligase complexes, which specifically determine protein substrate proteasomal degradation during plant growth and development, as well as biotic and abiotic stress. It has been found that the FBA (F-box associated) protein family is one of the largest subgroups of the widely prevalent F-box family and plays significant roles in plant development and stress response. However, the FBA gene family in poplar has not been systematically studied to date. In this study, a total of 337 F-box candidate genes were discovered based on the fourth-generation genome resequencing of P. trichocarpa. The domain analysis and classification of candidate genes revealed that 74 of these candidate genes belong to the FBA protein family. The poplar F-box genes have undergone multiple gene replication events, particularly in the FBA subfamily, and their evolution can be attributed to genome-wide duplication (WGD) and tandem duplication (TD). In addition, we investigated the P. trichocarpa FBA subfamily using the PlantGenIE database and quantitative real-time PCR (qRT-PCR); the results showed that they are expressed in the cambium, phloem and mature tissues, but rarely expressed in young leaves and flowers. Moreover, they are also widely involved in the drought stress response. At last, we selected and cloned PtrFBA60 for physiological function analysis and found that it played an important role in coping with drought stress. Taken together, the family analysis of FBA genes in P. trichocarpa provides a new opportunity for the identification of P. trichocarpa candidate FBA genes and elucidation of their functions in growth, development and stress response, thus demonstrating their utility in the improvement of P. trichocarpa.

Intermittent theta burst stimulation over the parietal cortex has a significant neural effect on working memory.

The crucial role of the parietal cortex in working memory (WM) storage has been identified by fMRI studies. However, it remains unknown whether repeated parietal intermittent theta-burst stimulation (iTBS) can improve WM. In this within-subject randomized controlled study, under the guidance of fMRI-identified parietal activation in the left hemisphere, 22 healthy adults received real and sham iTBS sessions (five consecutive days, 600 pulses per day for each session) with an interval of 9 months between the two sessions. Electroencephalography signals of each subject before and after both iTBS sessions were collected during a change detection task. Changes in contralateral delay activity (CDA) and K-score were then calculated to reflect neural and behavioral WM improvement. Repeated-measures ANOVA suggested that real iTBS increased CDA more than the sham one (p = .011 for iTBS effect). Further analysis showed that this effect was more significant in the left hemisphere than in the right hemisphere (p = .029 for the hemisphere-by-iTBS interaction effect). Pearson correlation analyses showed significant correlations for two conditions between CDA changes in the left hemisphere and K score changes (ps <.05). In terms of the behavioral results, significant K score changes after real iTBS were observed for two conditions, but a repeated-measures ANOVA showed a nonsignificant main effect of iTBS (p = .826). These results indicate that the current iTBS protocol is a promising way to improve WM capability based on the neural indicator (CDA) but further optimization is needed to produce a behavioral effect.

The Receptor-Like Kinase ERECTA Confers Improved Water Use Efficiency and Drought Tolerance to Poplar via Modulating Stomatal Density.

Poplar is one of the most important tree species in the north temperate zone, but poplar plantations are quite water intensive. We report here that CaMV 35S promoter-driven overexpression of the PdERECTA gene, which is a member of the LRR-RLKs family from Populus nigra × (Populus deltoides × Populus nigra), improves water use efficiency and enhances drought tolerance in triploid white poplar. PdERECTA localizes to the plasma membrane. Overexpression plants showed lower stomatal density and larger stomatal size. The abaxial stomatal density was 24-34% lower and the stomatal size was 12-14% larger in overexpression lines. Reduced stomatal density led to a sharp restriction of transpiration, which was about 18-35% lower than the control line, and instantaneous water use efficiency was around 14-63% higher in overexpression lines under different conditions. These phenotypic changes led to increased drought tolerance. PdERECTA overexpression plants not only survived longer after stopping watering but also performed better when supplied with limited water, as they had better physical and photosynthesis conditions, faster growth rate, and higher biomass accumulation. Taken together, our data suggest that PdERECTA can alter the development pattern of stomata to reduce stomatal density, which then restricts water consumption, conferring enhanced drought tolerance to poplar. This makes PdERECTA trees promising candidates for establishing more water use efficient plantations.

LncRNA CCAT1 functions as apoptosis inhibitor in podocytes via autophagy inhibition.

Podocyte apoptosis importantly contributes to various kidney diseases. Long noncoding RNAs Colon cancer-associated transcript-1 (CCAT-1) has been demonstrated for a critical role in cell proliferation. In the present study, the relationship between CCAT1 and popdocyte impairment, and the underlying mechanism was investigated. Podocytes were isolated from mice and then treated with tumor necrosis factor-α to simulate podocyte injury. After developed CCAT1 overexpression or knockdown, cell viabilities were determined with the CCK-8 assay, apoptosis was examined with Flow cytometry, the autophagy was observed by Western blot. Furthermore, phosphorylated PI3K and Akt expressions were examined. We found that after CCAT1 overexpression, the cell viability was significantly increased, apoptosis was significantly decreased, and autophagy was significantly inhibited, which was indicated by induced P62, LC3B-I and decreased LC3B-II. In addition, CCAT1 overexpression induced the levels of phosphorylated PI3K and Akt. With Rap treatment, these effects by CCAT1 were reversed. Furthermore, the results contrary to the effects by CCAT1 overexpression were presented after CCAT1 knockdown, and this was inhibited by 3-MA. Taken together, our results suggested that CCAT1 induction critically participated in apoptosis inhibition in podocytes through autophagy inhibition via increasing PI3K/Akt signaling. This might act as a promising therapeutic intervention for renal diseases associated with podocyte apoptosis.

ABF3 enhances drought tolerance via promoting ABA-induced stomatal closure by directly regulating ADF5 in Populus euphratica.

Water availability is a main limiting factor for plant growth, development, and distribution throughout the world. Stomatal movement mediated by abscisic acid (ABA) is particularly important for drought adaptation, but the molecular mechanisms in trees are largely unclear. Here, we isolated an ABA-responsive element binding factor, PeABF3, in Populus euphratica. PeABF3 was preferentially expressed in the xylem and young leaves, and was induced by dehydration and ABA treatments. PeABF3 showed transactivation activity and was located in the nucleus. To study its functional mechanism in poplar responsive to drought stress, transgenic triploid white poplars (Populus tomentosa 'YiXianCiZhu B385') overexpressing PeABF3 were generated. PeABF3 overexpression significantly enhanced stomatal sensitivity to exogenous ABA. When subjected to drought stress, PeABF3 overexpression maintained higher photosynthetic activity and promoted cell membrane integrity, resulting in increased water-use efficiency and enhanced drought tolerance compared with wild-type controls. Moreover, a yeast one-hybrid assay and an electrophoretic mobility shift assay revealed that PeABF3 activated the expression of Actin-Depolymerizing Factor-5 (PeADF5) by directly binding to its promoter, promoting actin cytoskeleton remodeling and stomatal closure in poplar under drought stress. Taken together, our results indicate that PeABF3 enhances drought tolerance via promoting ABA-induced stomatal closure by directly regulating PeADF5 expression.

PeSTZ1, a C2H2-type zinc finger transcription factor from Populus euphratica, enhances freezing tolerance through modulation of ROS scavenging by directly regulating PeAPX2.

In the present study, PeSTZ1, a cysteine-2/histidine-2-type zinc finger transcription factor, was isolated from the desert poplar, Populus euphratica, which serves as a model stress adaptation system for trees. PeSTZ1 was preferentially expressed in the young stems and was significantly up-regulated during chilling and freezing treatments. PeSTZ1 was localized to the nucleus and bound specifically to the PeAPX2 promoter. To examine the potential functions of PeSTZ1, we overexpressed it in poplar 84K hybrids (Populus alba × Populus glandulosa), which are known to be stress-sensitive. Upon exposure to freezing stress, transgenic poplars maintained higher photosynthetic activity and dissipated more excess light energy (in the form of heat) than wild-type poplars. Thus, PeSTZ1 functions as a transcription activator to enhance freezing tolerance without sacrificing growth. Under freezing stress, PeSTZ1 acts upstream of ASCORBATE PEROXIDASE2 (PeAPX2) and directly regulates its expression by binding to its promoter. Activated PeAPX2 promotes cytosolic APX that scavenges reactive oxygen species (ROS) under cold stress. PeSTZ1 may operate in parallel with C-REPEAT-BINDING FACTORS to regulate COLD-REGULATED gene expression. Moreover, PeSTZ1 up-regulation reduces malondialdehyde and ROS accumulation by activating the antioxidant system. Taken together, these results suggested that overexpressing PeSTZ1 in 84K poplar enhances freezing tolerance through the modulation of ROS scavenging via the direct regulation of PeAPX2 expression.

The effect of different light regimes on pigments in Coscinodiscus granii.

The influence of six different light regimes throughout the photosynthetically active radiation range (from 400 to 700 nm, including blue, green, yellow, red-orange, red, and white) at two intensities (100 and 300 µmol photons m-2 s-1) on pigmentation was assessed for the centric marine diatom Coscinodiscus granii for the first time. Chlorophyll (Chl) a and fucoxanthin were the dominating pigments in all treatments. The cellular concentrations of light harvesting pigment (Chl a, Chl c1 + c2, and fucoxanthin) were higher at 100 than at 300 µmol photons m-2 s-1 at all wavelengths, with the largest increases at red and blue light. The normalized concentrations of photoprotective pigments (violaxanthin, zeaxanthin, diadinoxanthin, and diatoxanthin) were higher at high light intensity than in cells grown at low light intensity. An increase in ß-carotene in low light conditions is expected as the increased Chl a was related to increased photosynthetic subunits which require ß-carotene (bound to photosystem core). At 300 µmol photons m-2 s-1, yellow light resulted in significantly lower concentration of most of the detected pigments than the other wavelengths. At 100 µmol photons m-2 s-1, W and B light led to statistically lower and higher concentration of most of the detected pigments than the other wavelengths, respectively.

[Rapid identification of Cordyceps and its products using DNA barcoding method].

Cordyceps is one of the most valuable traditional Chinese medicines. There are various counterfeits in markets because of high price and limited output. In this study,116 Cordyceps,146 hosts and 29 related products were collected and detected by using normal DNA barcoding technology and specific PCR method. The results indicated that Cordyceps and its adulterants could be distinguished from each other through DNA barcoding technology based on ITS and COⅠsequences. Two pairs specific primers ITSSF1/ITSSR1 and ITSSF2/ITSSR2 were developed to amplify 297 bp and 136 bp ITS regions of Cordyceps sinensis,respectively. It could be used to identify C. sinensis specifically and rapidly. Furthermore,specific primers ITSSF1/ITSSR1 and ITSSF2/ITSSR2 combined with ITS and COⅠsequences could differentiate powder Cordyceps from fermentation mycelia and could identify related products. Therefore,the method developed from this study could be applied to identify the powder of Cordyceps from fermentation mycelia and related products efficiently.

PeCHYR1, a ubiquitin E3 ligase from Populus euphratica, enhances drought tolerance via ABA-induced stomatal closure by ROS production in Populus.

Drought, a primary abiotic stress, seriously affects plant growth and productivity. Stomata play a vital role in regulating gas exchange and drought adaptation. However, limited knowledge exists of the molecular mechanisms underlying stomatal movement in trees. Here, PeCHYR1, a ubiquitin E3 ligase, was isolated from Populus euphratica, a model of stress adaptation in forest trees. PeCHYR1 was preferentially expressed in young leaves and was significantly induced by ABA (abscisic acid) and dehydration treatments. To study the potential biological functions of PeCHYR1, transgenic poplar 84K (Populus alba × Populus glandulosa) plants overexpressing PeCHYR1 were generated. PeCHYR1 overexpression significantly enhanced H2 O2 production and reduced stomatal aperture. Transgenic lines exhibited increased sensitivity to exogenous ABA and greater drought tolerance than that of WT (wild-type) controls. Moreover, up-regulation of PeCHYR1 promoted stomatal closure and decreased transpiration, resulting in strongly elevated WUE (water use efficiency). When exposed to drought stress, transgenic poplar maintained higher photosynthetic activity and biomass accumulation. Taken together, these results suggest that PeCHYR1 plays a crucial role in enhancing drought tolerance via ABA-induced stomatal closure caused by hydrogen peroxide (H2 O2 ) production in transgenic poplar plants.

Structure-based optics of centric diatom frustules: modulation of the in vivo light field for efficient diatom photosynthesis.

The optical properties of diatom silicate frustules inspire photonics and nanotechnology research. Whether light interaction with the nano-structure of the frustule also affects diatom photosynthesis has remained unclear due to lack of information on frustule optical properties under more natural conditions. Here we demonstrate that the optical properties of the frustule valves in water affect light harvesting and photosynthesis in live cells of centric diatoms (Coscinodiscus granii). Microscale cellular mapping of photosynthesis around localized spot illumination demonstrated optical coupling of chloroplasts to the valve wall. Photonic structures of the three-layered C. granii valve facilitated light redistribution and efficient photosynthesis in cell regions distant from the directly illuminated area. The different porous structure of the two sides of the valve exhibited photon trapping and forward scattering of blue light enhancing photosynthetic active radiation inside the cell. Photonic structures of diatom frustules thus alter the cellular light field with implications on diatom photobiology.

Poplar miR472a targeting NBS-LRRs is involved in effective defence against the necrotrophic fungus Cytospora chrysosperma.

The hemibiotroph Colletotrichum gloeosporioides and the necrotroph Cytospora chrysosperma cause poplar foliage and stem disease, respectively, resulting in substantial economic losses. In this study, Populus trichocarpa ptc-miR472a was down-regulated in leaves treated with salicylic acid, jasmonic acid (JA) or bacterial flagellin (flg22). Here, ptc-miR472a and a short tandem target mimic (STTM) of miR472a were overexpressed in P. alba × P. glandulosa, and overexpression lines of miR472a and silenced lines of STTM472a were generated. Compared with the STTM472a and wild type lines, lower reactive oxygen species accumulation was detected in miR472a overexpressing plants treated with flg22, C. gloeosporioides or C. chrysosperma. In addition, the miR472a overexpressing lines exhibited the highest susceptibility to the hemibiotroph, C. gloeosporioides, but the highest effective defence response to the necrotroph, C. chrysosperma. The JA/ethylene marker gene ERF1 was rapidly up-regulated in miR472a overexpressing plants. Furthermore, five phased, secondary, small interfering RNAs (phasiRNAs) were confirmed in the miR472a overexpressing and STTM472a lines, triggering phasiRNAs predicted to enhance NBS-LRR silencing. Taken together, our results revealed that ptc-miR472a exerts a key role in plant immunity to C. gloeosporioides and C. chrysosperma by targeting NBS-LRR transcripts. This study provides a new strategy and method in plant breeding to improve plant disease resistance.

Effects of abiotic factors on the nanostructure of diatom frustules-ranges and variability.

The intricate patterning of diatom silica frustules at nanometer-to-micrometer scales makes them of interest for a wide range of industrial applications. For some of these applications, a specific size range in nanostructure is required and may be achieved by selecting species with the desired properties. However, as all biological materials, diatom frustules exhibit variability in their morphological parameters and this variability can to some extent be affected and controlled by environmental conditions. In this review, we explore the effects of different environmental factors including salinity, heavy metals, temperature, pH, extracellular Si(OH)4 or Ge(OH)4 concentration, light regime, UV irradiance, long-term cultivation, and biotic factors on the nanostructure of diatom frustules. This compilation of studies illustrates that it is possible to affect the nanostructure of diatom frustules in vivo by controlling different environmental factors as well as by direct chemical modification of frustules. We compare these methods and present examples of how these changes affect the range of variability as well as comparing the magnitude of size changes of the most promising methods.

[Rapid identification of Gekko gecko by loop-mediated isothermal amplification based on 12S rRNA sequence].

Gekko gecko (Tokay Gecko) is a valuable traditional Chinese medicine. In this study, the loop-mediated isothermal amplification (LAMP) technique was introduced for visual rapid identification of G. gecko from adulterants. A total of sixty-five 12S rRNA sequences of fourteen species of G. gecko and its adulterants were obtained. The results showed that G. gecko could be identified from its adulterants through BLAST analysis based on 12S rRNA regions. The 12S rRNA sequences of ten batches of G. gecko were conserved. There were only two haplotypes and three variation sites in the available regions for primers design. Six specific LAMP primers were successfully designed online based on 12S rRNA sequences. The visual rapid detection of G. gecko could be achieved with the optimized conditions (64 °C for 1 h and 80 °C for 5 min). And the required minimal template concentration was 5 µg·L⁻¹ while conventional PCR with 0.5 mg·L⁻¹. Consequently, the LAMP method established from this study was rapid, specific, highly sensitive, and simple. It could be applied to detect G. gecko from its adulterants efficiently.

DNA Barcode for Identifying Folium Artemisiae Argyi from Counterfeits.

Folium Artemisiae Argyi is an important herb in traditional Chinese medicine. It is commonly used in moxibustion, medicine, etc. However, identifying Artemisia argyi is difficult because this herb exhibits similar morphological characteristics to closely related species and counterfeits. To verify the applicability of DNA barcoding, ITS2 and psbA-trnH were used to identify A. argyi from 15 closely related species and counterfeits. Results indicated that total DNA was easily extracted from all the samples and that both ITS2 and psbA-trnH fragments can be easily amplified. ITS2 was a more ideal barcode than psbA-trnH and ITS2+psbA-trnH to identify A. argyi from closely related species and counterfeits on the basis of sequence character, genetic distance, and tree methods. The sequence length was 225 bp for the 56 ITS2 sequences of A. argyi, and no variable site was detected. For the ITS2 sequences, A. capillaris, A. anomala, A. annua, A. igniaria, A. maximowicziana, A. princeps, Dendranthema vestitum, and D. indicum had single nucleotide polymorphisms (SNPs). The intraspecific Kimura 2-Parameter distance was zero, which is lower than the minimum interspecific distance (0.005). A. argyi, the closely related species, and counterfeits, except for Artemisia maximowicziana and Artemisia sieversiana, were separated into pairs of divergent clusters by using the neighbor joining, maximum parsimony, and maximum likelihood tree methods. Thus, the ITS2 sequence was an ideal barcode to identify A. argyi from closely related species and counterfeits to ensure the safe use of this plant.