Transcriptomic and metabolomic profiling provide insight into the role of sugars and hormones in leaf senescence of Pinellia ternata.

KEY MESSAGE: The interaction network and pathway map uncover the potential crosstalk between sugar and hormone metabolisms as a possible reason for leaf senescence in P. ternata. Pinellia ternata, an environmentally sensitive medicinal plant, undergoes leaf senescence twice a year, affecting its development and yield. Understanding the potential mechanism that delays leaf senescence could theoretically decrease yield losses. In this study, a typical senescent population model was constructed, and an integrated analysis of transcriptomic and metabolomic profiles of P. ternata was conducted using two early leaf senescence populations and two stay-green populations. The result showed that two key gene modules were associated with leaf senescence which were mainly enriched in sugar and hormone signaling pathways, respectively. A network constructed by unigenes and metabolisms related to the obtained two pathways revealed that several compounds such as D-arabitol and 2MeScZR have a higher significance ranking. In addition, a total of 130 hub genes in this network were categorized into 3 classes based on connectivity. Among them, 34 hub genes were further analyzed through a pathway map, the potential crosstalk between sugar and hormone metabolisms might be an underlying reason of leaf senescence in P. ternata. These findings address the knowledge gap regarding leaf senescence in P. ternata, providing candidate germplasms for molecular breeding and laying theoretical basis for the realization of finely regulated cultivation in future.

[Cloning and expression pattern analysis of abscisic acid receptor gene McPYL4 in Mentha canadensis].

Mentha canadensis is a traditional Chinese herb with great medicinal and economic value. Abscisic acid(ABA) receptor PYLs have important roles in plant growth and development and response to adversity. The M. canadensis McPYL4 gene was cloned, and its protein characteristics, gene expression, and protein interactions were analyzed, so as to provide genetic resources for genetic improvement and molecular design breeding for M. canadensis resistance. Therefore, the protein characteristics, subcellular localization, gene expression pattern, and protein interactions of McPYL4 were analyzed by bioinformatics analysis, transient expression of tobacco leaves, RT-qPCR, and yeast two-hybrid(Y2H) techniques. The results showed that the McPYL4 gene was 621 bp in length, encoding 206 amino acids, and its protein had the conserved structural domain of SRPBCC and was highly homologous with Salvia miltiorrhiza SmPYL4. McPYL4 protein was localized to the cell membrane and nucleus. The McPYL4 gene was expressed in all tissue of M. canadensis, with the highest expression in roots, followed by leaves, and it showed a pattern of up-regulation followed by down-regulation in leaves 1-8. In both leaves and roots, the McPYL4 gene responded to the exogenous hormones ABA, MeJA, and the treatments of drought, AlCl_3, NaCl, CdCl_2, and CuCl_2. Moreover, McPYL4 was up-regulated for expression in both leaves and roots under the MeJA treatment, as well as in leaves treated with AlCl_3 stress for 1 h, whereas McPYL4 showed a tendency to be down-regulated in both leaves and roots under other treatments. Protein interactions showed that McPYL4 interacted with AtABI proteins in an ABA-independent manner. This study demonstrated that McPYL4 responded to ABA, JA, and several abiotic stress treatments, and McPYL4 was involved in ABA signaling in M. canadensis and thus in the regulation of leaf development and various abiotic stresses in M. canadensis.

Comparative transcriptome revealed the molecular responses of Aconitum carmichaelii Debx. to downy mildew at different stages of disease development.

BACKGROUND: Aconitum carmichaelii Debx. has been widely used as a traditional medicinal herb for a long history in China. It is highly susceptible to various dangerous diseases during the cultivation process. Downy mildew is the most serious leaf disease of A. carmichaelii, affecting plant growth and ultimately leading to a reduction in yield. To better understand the response mechanism of A. carmichaelii leaves subjected to downy mildew, the contents of endogenous plant hormones as well as transcriptome sequencing were analyzed at five different infected stages. RESULTS: The content of 3-indoleacetic acid, abscisic acid, salicylic acid and jasmonic acid has changed significantly in A. carmichaelii leaves with the development of downy mildew, and related synthetic genes such as 9-cis-epoxycarotenoid dioxygenase and phenylalanine ammonia lyase were also significant for disease responses. The transcriptomic data indicated that the differentially expressed genes were primarily associated with plant hormone signal transduction, plant-pathogen interaction, the mitogen-activated protein kinase signaling pathway in plants, and phenylpropanoid biosynthesis. Many of these genes also showed potential functions for resisting downy mildew. Through weighted gene co-expression network analysis, the hub genes and genes that have high connectivity to them were identified, which could participate in plant immune responses. CONCLUSIONS: In this study, we elucidated the response and potential genes of A. carmichaelii to downy mildew, and observed the changes of endogenous hormones content at different infection stages, so as to contribute to the further screening and identification of genes involved in the defense of downy mildew.

The complete chloroplast genome of Mussaenda pubescens and phylogenetic analysis.

The chloroplast (cp) genome sequence of Mussaenda pubescens, a promising resource that is used as a traditional medicine and drink, is important for understanding the phylogenetic relationships among the Mussaenda family and genetic improvement and reservation. This research represented the first comprehensive description of the morphological characteristics of M. pubescens, as well as an analysis of the complete cp genome and phylogenetic relationship. The results indicated a close relationship between M. pubescens and M. hirsutula based on the morphological characteristics of the flower and leaves. The cp was sequenced using the Illumina NovaSeq 6000 platform. The results indicated the cp genome of M. pubescens spanned a total length of 155,122 bp, including a pair of inverted repeats (IRA and IRB) with a length of 25,871 bp for each region, as well as a large single-copy (LSC) region and a small single-copy (SSC) region with lengths of 85,370 bp and 18,010 bp, respectively. The results of phylogenetic analyses demonstrated that species within the same genus displayed a tendency to group closely together. It was suggested that Antirhea, Cinchona, Mitragyna, Neolamarckia, and Uncaria might have experienced an early divergence. Furthermore, M. hirsutula showed a close genetic connection to M. pubescens, with the two species having partially overlapping distributions in China. This study presents crucial findings regarding the identification, evolution, and phylogenetic research on Mussaenda plants, specifically targeting M. pubescens.

The transcription factor MYB1 activates DGAT2 transcription to promote triacylglycerol accumulation in sacha inchi (Plukenetia volubilis L.) leaves under heat stress.

Triacylglycerol (TAG) accumulation is frequently triggered in vegetative tissues experiencing heat stress, which may increases plant basal plant thermo-tolerance by sequestering the toxic lipid intermediates that contribute to membrane damage or cell death under stress conditions. However, stress-responsive TAG biosynthesis and the underlying regulatory mechanisms are not fully understood. Here, we investigated the lipidomic and transcriptomic landscape under heat stress in the leaves of sacha inchi (Plukenetia volubilis L.), an important oilseed crop in tropical regions. Under heat stress (45 °C), the content of polyunsaturated TAGs (e.g., TAG18:2 and TAG18:3) and total TAGs were significantly higher, while those of unsaturated sterol esters, including ZyE 28:4, SiE 18:2 and SiE 18:3, were dramatically lower. Transcriptome analysis showed that the expression of PvDGAT2-2, encoding a type II diacylglycerol acyltransferase (DGAT) that is critical for TAG biosynthesis, was substantially induced under heat stress. We confirmed the function of PvDGAT2-2 in TAG production by complementing a yeast mutant defective in TAG biosynthesis. Importantly, we also identified the heat-induced transcription factor PvMYB1 as an upstream activator of PvDGAT2-2 transcription. Our findings on the molecular mechanism leading to TAG biosynthesis in leaves exposed to heat stress have implications for improving the biotechnological production of TAGs in vegetative tissues, offering an alternative to seeds.

Dynamic DNA Methylation Regulates Season-Dependent Secondary Metabolism in the New Shoots of Tea Plants.

Plant secondary metabolites are critical quality-conferring compositions of plant-derived beverages, medicines, and industrial materials. The accumulations of secondary metabolites are highly variable among seasons; however, the underlying regulatory mechanism remains unclear, especially in epigenetic regulation. Here, we used tea plants to explore an important epigenetic mark DNA methylation (5mC)-mediated regulation of plant secondary metabolism in different seasons. Multiple omics analyses were performed on spring and summer new shoots. The results showed that flavonoids and theanine metabolism dominated in the metabolic response to seasons in the new shoots. In summer new shoots, the genes encoding DNA methyltransferases and demethylases were up-regulated, and the global CG and CHG methylation reduced and CHH methylation increased. 5mC methylation in promoter and gene body regions influenced the seasonal response of gene expression; the amplitude of 5mC methylation was highly correlated with that of gene transcriptions. These differentially methylated genes included those encoding enzymes and transcription factors which play important roles in flavonoid and theanine metabolic pathways. The regulatory role of 5mC methylation was further verified by applying a DNA methylation inhibitor. These findings highlight that dynamic DNA methylation plays an important role in seasonal-dependent secondary metabolism and provide new insights for improving tea quality.

Morpho-anatomical characterization and DNA barcoding of Artemesia vulgaris L.

Artemisia vulgaris L. belongs to Asteraceae, is a herbal plant that has various benefits in the medical field, so that its use in the medical field can be explored optimally, the plant must be thoroughly identified. This study aims to identify A. vulgaris both in terms of descriptive morpho-anatomy and DNA barcoding using BLAST and phylogenetic tree reconstruction. The morpho-anatomical character was observed on root, stem, and leaf. DNA barcoding analysis was carried out through amplification and alignment of the rbcL and matK genes. All studies were conducted on three samples from Taman Husada (Medicinal Plant Garden) Graha Famili Surabaya, Indonesia. The anatomical slide was prepared by the paraffin method. Morphological studies revealed that the leaves of A. vulgaris both on the lower-middle part and on the upper part of the stem have differences, especially in the character of the stipules, petioles, and incisions they have. Meanwhile, from the study of anatomy, A. vulgaris has an anomocytic type of stomata and its distribution is mostly on the ventral part of the leaves. Through the BLAST process and phylogenetic tree reconstruction, the plant sequences being studied are closely related to several species of the genus Artemisia as indicated by a percentage identity above 98% and branch proximity between taxa in the reconstructed phylogenetic tree.

Comprehensive analysis of fresh tea (Camellia sinensis cv. Lingtou Dancong) leaf quality under different nitrogen fertilization regimes.

Our study investigated the impact of nitrogen fertilization at 0, 150, 300, and 450 kg/ha on the non-volatile and volatile substances, as well as gene expression in fresh leaves from Lingtou tea plants. We found that applying nitrogen at 450 kg/ha notably increased total polyphenols (TPs) and free amino acids (AAs) while decreasing the TP to AA ratio (TP/AA) and total catechins (TC) contents. Chlorophyll, caffeine (CAF) and theanine accumulated to a greater extent with nitrogen application rates of 150, 300, and 450 kg/ha, respectively, six substances - TP, CAF, TC, theanine, epigallocatechin (EGC), and AA - as key contributors to the taste quality of LTDC. Additionally, five substances with variable importance in projections (VIP) ≥ 1 and odor activation values (OAV) ≥ 1, notably linalool and cis-linalool oxide (furanoid), significantly contributed to the tea's overall aroma. Furthermore, applying 300 kg/ha nitrogen upregulated the dihydroflavonol reductase (DFR)gene, likely causing catechin decrease.

A key mutation in magnesium chelatase I subunit leads to a chlorophyll-deficient mutant of tea (Camellia sinensis).

Tea (Camellia sinensis) is a highly important beverage crop renowned for its unique flavour and health benefits. Chlorotic mutants of tea, known worldwide for their umami taste and economic value, have gained global popularity. However, the genetic basis of this chlorosis trait remains unclear. In this study, we identified a major-effect quantitative trait locus (QTL), qChl-3, responsible for the chlorosis trait in tea leaves, linked to a non-synonymous polymorphism (G1199A) in the magnesium chelatase I subunit (CsCHLI). Homozygous CsCHLIA plants exhibited an albino phenotype due to defects in magnesium protoporphyrin IX and chlorophylls in the leaves. Biochemical assays revealed that CsCHLI mutations did not affect subcellular localization or interactions with CsCHLIG and CsCHLD. However, combining CsCHLIA with CsCHLIG significantly reduced ATPase activity. RNA-seq analysis tentatively indicated that CsCHLI inhibited photosynthesis and enhanced photoinhibition, which in turn promoted protein degradation and increased the amino acid levels in chlorotic leaves. RT-qPCR and enzyme activity assays confirmed the crucial role of asparagine synthetase and arginase in asparagine and arginine accumulation, with levels increasing over 90-fold in chlorotic leaves. Therefore, this study provides insights into the genetic mechanism underlying tea chlorosis and the relationship between chlorophyll biosynthesis and amino acid metabolism.

Kinetic modeling identifies targets for engineering improved photosynthetic efficiency in potato (Solanum tuberosum cv. Solara).

Potato (Solanum tuberosum) is a significant non-grain food crop in terms of global production. However, its yield potential might be raised by identifying means to release bottlenecks within photosynthetic metabolism, from the capture of solar energy to the synthesis of carbohydrates. Recently, engineered increases in photosynthetic rates in other crops have been directly related to increased yield - how might such increases be achieved in potato? To answer this question, we derived the photosynthetic parameters Vcmax and Jmax to calibrate a kinetic model of leaf metabolism (e-Photosynthesis) for potato. This model was then used to simulate the impact of manipulating the expression of genes and their protein products on carbon assimilation rates in silico through optimizing resource investment among 23 photosynthetic enzymes, predicting increases in photosynthetic CO2 uptake of up to 67%. However, this number of manipulations would not be practical with current technologies. Given a limited practical number of manipulations, the optimization indicated that an increase in amounts of three enzymes - Rubisco, FBP aldolase, and SBPase - would increase net assimilation. Increasing these alone to the levels predicted necessary for optimization increased photosynthetic rate by 28% in potato.

Integrated metabolomics and transcriptomic analysis reveals metabolic changes of flavor compounds of Camellia assamica host plant after parasitized by Viscumarticulatum.

Tea is one of the most popular beverages, it has many health benefits and flavor properties due to the presence of numerous secondary metabolites. Camellia assamica is also a main source of tea, which is mainly planted in the regions of southwest China. In this study, a non-targeted and targeted metabolomics analysis and sensory evaluation on tea leaves with and without mistletoe (Viscum articulatum) was carried out using liquid chromatography-mass spectrometry. RNA-seq-based transcriptomic analysis was conducted in parallel on the same samples, subsequently gene expression and metabolic differentiation were also investigated. Tea leaves with mistletoe presented much lower contents of (-)-catechin, (-)-epicatechin, (-)-gallocatechin gallate and (-)-epicatechin gallate, but significantly higher levels of free amino acids including Arg, Asp, GABA and Gln than that without mistletoe. Transcriptomic analysis also confirmed the main differentially expressed genes (DEGs) containing phenylpropanoid and flavonoid biosynthesis were down-regulated, but genes of amino acid biosynthesis were up-regulated. qRT-PCR analysis further revealed that the relative expression of CsCHS, CsC4H, CsANS, CsLAR, and CsF3H was hindered, while CsglyA and CsilvE expression was increased.

Integrative Transcriptome and Metabolome Analysis to Reveal Red Leaf Coloration in Shiya Tea (Adinandra nitida).

BACKGROUND: Adinandra nitida, commonly known as Shiya tea, is a healthcare drink enriched in several phenolic acids and flavonoids, with a purple-red leaf variety possessing a unique flavor and a higher economic value. However, the mechanisms underlying leaf coloration and senescence discoloration remain unknown. METHODS: Here, we compared both varieties of A. nitida (purple-red leaf, RL, and green leaf, GL) at two stages of development. To make sure the difference in leaf color in these four groups, several indexes, leaf colorimetric differences, H2O2 content in leaf cells, and antioxidant enzymes activities (superoxide dismutase (SOD), catalase (CAT)) were measured. With the integration of metabolome and transcriptome becoming a trend, metabolites in four groups were detected using an Ultra performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) system, and the transcriptome was performed after the extraction of RNA in samples. Afterward, the activities of laccase (LAC) and peroxidase (POD) were measured for further analysis. RESULTS: The deeper or discoloration of leaf color was not caused by the reactive oxygen species (ROS) stress because the H2O2 content was similar for each group. And the SOD and CAT activities improved significantly in young leaves, especially RL_young. Metabolome data showed a large shift in four groups. By focusing on the variation of flavonoids and 1079 metabolites detected in both varieties, along with the accumulation of flavonoids and tannins, proanthocyanins (PAs) were mostly accumulated in young RL. Differential analysis of expressed genes (DEGs) revealed six genes associated with leaf discoloration as hub factors, of which ANRs (ANR1 and ANR2) were positively correlated with the accumulation of PA in RL. CONCLUSIONS: Using integrate analysis of metabolome and transcriptome, our results revealed that six structural genes found in proanthocyanin biosynthesis, two reductases (ANR), two oxidative polymerases (POD64, LAC17) and two TFs (bHLH3 and MYB4) related to biosynthesis and polymerization of proanthocyanins were associated with not only the difference of GL and RL but also the faded coloration in two RL groups (RL_young and RL_old), which provided a foundation for further research on an understanding of the regulatory genes and the enzymes specific for proanthocyanidin biosynthesis, facilitating the genetic engineering of crops for beneficial metabolite accumulation.

Integrated Cytological, Physiological, and Transcriptome Analyses Provide Insight into the Albino Phenotype of Chinese Plum (Prunus salicina).

Albino seedlings that arise during seed reproduction can have a significant impact on plant growth and breeding. In this research, we present the first report of albino occurrences in the seed reproduction process of Prunus salicina and describe the cytological, physiological, and transcriptomic changes observed in albino seedlings. The albino seedlings which were observed in several plum cultivars exhibited abnormal chloroplast ultrastructure and perturbed stomatal structure. Compared to normal seedlings, the photosynthetic pigment contents in albino seedlings decreased by more than 90%, accompanied by significant reductions in several chlorophyll fluorescence parameters. Furthermore, substantially changed photosynthetic parameters indicated that the photosynthetic capacity and stomatal function were impaired in albino seedlings. Additionally, the activities of the antioxidant enzyme were drastically altered against the background of higher proline and lower ascorbic acid in leaves of albino seedlings. A total of 4048 differentially expressed genes (DEGs) were identified through transcriptomic sequencing, and the downregulated DEGs in albino seedlings were greatly enriched in the pathways for photosynthetic antenna proteins and flavonoid biosynthesis. GLK1 and Ftsz were identified as candidate genes responsible for the impaired chloroplast development and division in albino seedlings. Additionally, the substantial decline in the expression levels of examined photosystem-related chloroplast genes was validated in albino seedlings. Our findings shed light on the intricate physiological and molecular mechanisms driving albino plum seedling manifestation, which will contribute to improving the reproductive and breeding efforts of plums.

Transcriptome and Biochemical Analyses of a Chlorophyll-Deficient Bud Mutant of Tea Plant (Camellia sinensis).

Tea leaf-color mutants have attracted increasing attention due to their accumulation of quality-related biochemical components. However, there is limited understanding of the molecular mechanisms behind leaf-color bud mutation in tea plants. In this study, a chlorina tea shoot (HY) and a green tea shoot (LY) from the same tea plant were investigated using transcriptome and biochemical analyses. The results showed that the chlorophyll a, chlorophyll b, and total chlorophyll contents in the HY were significantly lower than the LY's, which might have been caused by the activation of several genes related to chlorophyll degradation, such as SGR and CLH. The down-regulation of the CHS, DFR, and ANS involved in flavonoid biosynthesis might result in the reduction in catechins, and the up-regulated GDHA and GS2 might bring about the accumulation of glutamate in HY. RT-qPCR assays of nine DEGs confirmed the RNA-seq results. Collectively, these findings provide insights into the molecular mechanism of the chlorophyll deficient-induced metabolic change in tea plants.

Identification of novel flavin-dependent monooxygenase from Strobilanthes Cusia reveals molecular basis of indoles' biosynthetic logic.

BACKGROUND: Strobilanthes cusia (Nees) Kuntze is a traditional medical plant distributed widely in south China. The indole compounds that originated from the plant are responsible for its pharmacological activities. However, the reason why indole ingredients are accumulated in this herb and how it is biosynthesized has remained largely unknown. RESULTS: In this study, metabolic and transcriptional profiling measurement experiments of different S. cusia organs were carried out to understand the underlying molecular basis of indoles' biosynthetic logic. A metabolic investigation demonstrated that the indoles are primarily accumulated mainly in aerial parts, particularly in leaves. RNA-seq was employed to reveal the organ specific accumulation of indoles in different S. cusia organs. Meanwhile, a flavin-dependent monooxygenase gene (ScFMO1) was found in S. cusia, and it has capacity to produce indoxyl from indole by the fermentation assay. Finally, we assessed the outcomes of transient expression experiment in tobacco and confirmed that ScFMO1 localizes in cytoplasm. CONCLUSIONS: Our results suggest that ScFMO1 plays a key role in biosynthesis of indoles (Indigo, indirubin, indican, etc.), it will be useful for illuminating the molecular basis of the medicinal indoles' biosynthesis and developing strategies for improving their yields.

Identification of P450 Candidates Associated with the Biosynthesis of Physalin-Class Compounds in Physalis angulata.

The Physalis genus has long been used as traditional medicine in the treatment of various diseases. Physalins, the characteristic class of compounds in this genus, are major bioactive constituents. To date, the biogenesis of physalins remains largely unknown, except for the recently established knowledge that 24-methyldesmosterol is a precursor of physalin. To identify the genes encoding P450s that are putatively involved in converting 24-methyldesmosterol to physalins, a total of 306 P450-encoding unigenes were retrieved from our recently constructed P. angulata transcriptome. Extensive phylogenetic analysis proposed 21 P450s that might participate in physalin biosynthesis. To validate the candidates, we developed a virus-induced gene silencing (VIGS) system for P. angulata, and four P450 candidates were selected for the VIGS experiments. The reduction in the transcripts of the four P450 candidates by VIGS all led to decreased levels of physalin-class compounds in the P. angulata leaves. Thus, this study provides a number of P450 candidates that are likely associated with the biosynthesis of physalin-class compounds, forming a strong basis to reveal the unknown physalin biosynthetic pathway in the future.

Novel insights into the role of leaf in the cutting process of Camellia sinensis using physiological, biochemical and transcriptome analyses.

Cuttage is the preferred approach for rapid propagation of many species including tea plant (Camellia sinensis). Leaf serves as a key part of nodal cutting, but there is a lack of systematic research on its role in the cutting process. In this study, 24 tea cultivars were employed to prove the necessity of leaf and light during cuttage. Further leaf physiological parameters found that lower net photosynthesis rate probably promoted rooting. Phytohormone content detection showed that auxin content and composition pattern were related to rooting ability. Leaf transcriptome analyses of cuttings from a representative easy-to-root cultivar (cv. Echa 10) revealed that genes involved in carbohydrate metabolism, signal transduction, metabolite biosynthesis and transportation were differentially expressed during the rooting process. CsTSA1, CsYUC10, CsAUX1s, CsPIN3 and CsPIN5 were selected as the candidate genes, which possibly regulate the rooting of nodal cuttings. These results illustrate the necessity of the leaf in cuttage and provide molecular evidence that leaf is an important place for signal transduction, metabolite synthesis and transport during the rooting process.

Transcriptomic and physiological shade avoidance responses in potato (Solanum tuberosum) plants.

Plants detect competitors in shaded environments by perceiving a reduction in photosynthetically active radiation (PAR) and the reduction between the red and far-red light (R:FR) ratio and blue photons. These light signals are detected by phytochromes and cryptochromes, which trigger shade avoidance responses such as shoot and petiole elongation and lead to increased susceptibility to pathogen attack. We studied morphological, anatomical, and photosynthesis differences in potato plants (Solanum tuberosum var. Spunta) exposed to sunlight or simulated shade in a greenhouse. We found that simulated shade strongly induced stem and internode elongation with a higher production of free auxin in stems and a lower production of tubers. The mesophyll thickness of the upper leaves of plants grown in simulated shade was lower, but the epidermis was wider compared with the leaves of plants cultivated in sunlight. In addition, the photosynthesis rate was lower in the upper leaves exposed to nonsaturated irradiances and higher in the basal leaves at saturated irradiances compared with control plants. RNA-seq analysis showed that 146 and 155 genes were up- and downregulated by shade, respectively. By quantitative reverse transcription polymerase chain reaction, we confirmed that FLOWERING LOCUS T (FT), WRKY-like, and PAR1b were induced, while FLAVONOL 4-SULFOTRANSFERASE was repressed under shade. In shaded plants, leaves and tubers were more susceptible to the necrotrophic fungus Botrytis cinerea attack. Overall, our work demonstrates configurational changes between growth and defense decisions in potato plants cultivated in simulated shade.

Dissected Leaf 1 encodes an MYB transcription factor that controls leaf morphology in potato.

KEY MESSAGE: The transcription factor StDL1 regulates dissected leaf formation in potato and the genotype frequency of recessive Stdl1/Stdl1, which results in non-dissected leaves, has increased in cultivated potatoes. Leaf morphology is a key trait of plants, influencing plant architecture, photosynthetic efficiency and yield. Potato (Solanum tuberosum L.), the third most important food crop worldwide, has a diverse leaf morphology. However, despite the recent identification of several genes regulating leaf formation in other plants, few genes involved in potato leaf development have been reported. In this study, we identified an R2R3 MYB transcription factor, Dissected Leaf 1 (StDL1), regulating dissected leaf formation in potato. A naturally occurring allele of this gene, Stdl1, confers non-dissected leaves in young seedlings. Knockout of StDL1 in a diploid potato changes the leaf morphology from dissected to non-dissected. Experiments in N. benthamiana and yeast show that StDL1 is a transcriptional activator. Notably, by calculating the genotype frequency of the Stdl1/Stdl1 in 373-potato accessions, we found that it increases significantly in cultivated potatoes. This work reveals the genetic basis of dissected leaf formation in potato and provides insights into plant leaf morphology.

[Distinguishing between Artemisia stolonifera and A. argyi by specific PCR of leaves and non-glandular trichomes].

Artemisia stolonifera is a relative of A. argyi. The two species are difficult to be distinguished due to the similarity in leaf shape and have even less distinctive features after processing. This study aims to establish a method to quickly distinguish between them. At the same time, we examined the reasonability and applicability of the specific polymerase chain reaction(PCR) method. The C/T single nucleotide polymorphism was detected at the position 202 of the sequence, based on which specific primers were designed to identify these two species. The PCR with the specific primer JNC-F and the universal primer ITS3R produced a specific band at 218 bp for A. argyi and no band for A. stolonifera, which can be used to detect at least 3% of A. argyi samples mixed in A. stolonifera samples. The PCR with the specific primer KY-F and the universal primer ITS3R produced a specific band at 218 bp for A. stolonifera and no band for A. argyi, which can be used to detect at least 5% of A. stolonifera samples mixed with A. argyi. The limit of detection of the established method was 5 ng DNA. The established PCR method can accurately distinguish between A. stolonifera and A. argyi, which provides an experimental basis for the quality control of A. stolonifera and determines whether the herbs are adulterated.