Characteristics of NAC transcription factors in Solanaceae crops and their roles in responding to abiotic and biotic stresses.

As one of the largest transcription factor (TF) families in plants, the NAC (NAM, ATAF1/2, and CUC2) family plays important roles in response pathways to various abiotic and biotic stresses, such as drought, high salinity, low temperature, and pathogen infection. Although, there are a number of reviews on the involvement of NAC TF in plant responses to biotic and abiotic stresses, most of them are focused on the model plants Arabidopsis thaliana and Oryza sativa, and there is a lack of systematic evaluation of specific species. Solanaceae, the world's third most significant cash crop, has been seriously affected by environmental disturbances in recent years in terms of yield and quality, posing a severe threat to global food security. This review focuses on the functional roles of NAC transcription factors in response to external stresses involved in five important Solanaceae crops: tomato, potato, pepper, eggplant and tobacco, and analyzes the affinities between them. It will provide resources for stress-resistant breeding of Solanaceae crops using transgenic technology.

EpMYB2 positively regulates chicoric acid biosynthesis by activating both primary and specialized metabolic genes in purple coneflower.

Chicoric acid is the major active ingredient of the world-popular medicinal plant purple coneflower (Echinacea purpurea (L.) Menoch). It is recognized as the quality index of commercial hot-selling Echinacea products. While the biosynthetic pathway of chicoric acid in purple coneflower has been elucidated recently, its regulatory network remains elusive. Through co-expression and phylogenetic analysis, we found EpMYB2, a typical R2R3-type MYB transcription factor (TF) responsive to methyl jasmonate (MeJA) simulation, is a positive regulator of chicoric acid biosynthesis. In addition to directly regulating chicoric acid biosynthetic genes, EpMYB2 positively regulates genes of the upstream shikimate pathway. We also found that EpMYC2 could activate the expression of EpMYB2 by binding to its G-box site, and the EpMYC2-EpMYB2 module is involved in the MeJA-induced chicoric acid biosynthesis. Overall, we identified an MYB TF that positively regulates the biosynthesis of chicoric acid by activating both primary and specialized metabolic genes. EpMYB2 links the gap between the JA signaling pathway and chicoric acid biosynthesis. This work opens a new direction toward engineering purple coneflower with higher medicinal qualities.

Circadian rhythm response and its effect on photosynthetic characteristics of the Lhcb family genes in tea plant.

BACKGROUND: The circadian clock, also known as the circadian rhythm, is responsible for predicting daily and seasonal changes in the environment, and adjusting various physiological and developmental processes to the appropriate times during plant growth and development. The circadian clock controls the expression of the Lhcb gene, which encodes the chlorophyll a/b binding protein. However, the roles of the Lhcb gene in tea plant remain unclear. RESULTS: In this study, a total of 16 CsLhcb genes were identified based on the tea plant genome, which were distributed on 8 chromosomes of the tea plant. The promoter regions of CsLhcb genes have a variety of cis-acting elements including hormonal, abiotic stress responses and light response elements. The CsLhcb family genes are involved in the light response process in tea plant. The photosynthetic parameter of tea leaves showed rhythmic changes during the two photoperiod periods (48 h). Stomata are basically open during the day and closed at night. Real-time quantitative PCR results showed that most of the CsLhcb family genes were highly expressed during the day, but were less expressed at night. CONCLUSIONS: Results indicated that CsLhcb genes were involved in the circadian clock process of tea plant, it also provided potential references for further understanding of the function of CsLhcb gene family in tea plant.

Genome-wide identification, subcellular localization, and expression analysis of the phosphatidyl ethanolamine-binding protein family reveals the candidates involved in flowering and yield regulation of Tartary buckwheat (Fagopyrum tataricum).

Background: PEBP (phosphatidyl ethanolamine-binding protein) is widely found in eukaryotes including plants, animals and microorganisms. In plants, the PEBP family plays vital roles in regulating flowering time and morphogenesis and is highly associated to agronomic traits and yields of crops, which has been identified and characterized in many plant species but not well studied in Tartary buckwheat (Fagopyrum tataricum Gaertn.), an important coarse food grain with medicinal value. Methods: Genome-wide analysis of FtPEBP gene family members in Tartary buckwheat was performed using bioinformatic tools. Subcellular localization analysis was performed by confocal microscopy. The expression levels of these genes in leaf and inflorescence samples were analyzed using qRT-PCR. Results: Fourteen Fagopyrum tataricum PEBP (FtPEBP) genes were identified and divided into three sub-clades according to their phylogenetic relationships. Subcellular localization analysis of the FtPEBP proteins in tobacco leaves indicated that FT- and TFL-GFP fusion proteins were localized in both the nucleus and cytoplasm. Gene structure analysis showed that most FtPEBP genes contain four exons and three introns. FtPEBP genes are unevenly distributed in Tartary buckwheat chromosomes. Three tandem repeats were found among FtFT5/FtFT6, FtMFT1/FtMFT2 and FtTFL4/FtTFL5. Five orthologous gene pairs were detected between F. tataricum and F. esculentum. Seven light-responsive, nine hormone-related and four stress-responsive elements were detected in FtPEBPs promoters. We used real-time PCR to investigate the expression levels of FtPEBPs among two flowering-type cultivars at floral transition time. We found FtFT1/FtFT3 were highly expressed in leaf and young inflorescence of early-flowering type, whereas they were expressed at very low levels in late-flowering type cultivars. Thus, we deduced that FtFT1/FtFT3 may be positive regulators for flowering and yield of Tartary buckwheat. These results lay an important foundation for further studies on the functions of FtPEBP genes which may be utilized for yield improvement.

Genome-wide identification of tea plant (Camellia sinensis) BAHD acyltransferases reveals their role in response to herbivorous pests.

BACKGROUND: BAHD acyltransferases are among the largest metabolic protein domain families in the genomes of terrestrial plants and play important roles in plant growth and development, aroma formation, and biotic and abiotic stress responses. Little is known about the BAHDs in the tea plant, a cash crop rich in secondary metabolites. RESULTS: In this study, 112 BAHD genes (CsBAHD01-CsBAHD112) were identified from the tea plant genome, with 85% (98/112) unevenly distributed across the 15 chromosomes. The number of BAHD gene family members has significantly expanded from wild tea plants to the assamica type to the sinensis type. Phylogenetic analysis showed that they could be classified into seven subgroups. Promoter cis-acting element analysis revealed that they contain a large number of light, phytohormones, and stress-responsive elements. Many members displayed tissue-specific expression patterns. CsBAHD05 was expressed at more than 500-fold higher levels in purple tea leaves than in green tea leaves. The genes exhibiting the most significant response to MeJA treatment and feeding by herbivorous pests were primarily concentrated in subgroups 5 and 6. The expression of 23 members of these two subgroups at different time points after feeding by tea green leafhoppers and tea geometrids was examined via qPCR, and the results revealed that the expression of CsBAHD93, CsBAHD94 and CsBAHD95 was significantly induced after the tea plants were subjected to feeding by both pricking and chewing pests. Moreover, based on the transcriptome data for tea plants being fed on by these two pests, a transcriptional regulatory network of different transcription factor genes coexpressed with these 23 members was constructed. CONCLUSIONS: Our study provides new insights into the role of BAHDs in the defense response of tea plants, and will facilitate in-depth studies of the molecular function of BAHDs in resistance to herbivorous pests.

Potato miR394 targets StA/N-INVE and StLCR to negatively regulate late blight resistance.

MicroRNAs (miRNAs) are small noncoding RNAs in eukaryotes. Plant endogenous miRNAs play pivotal roles in regulating plant development and defense responses. MicroRNA394 (miR394) has been reported to regulate plant development, abiotic stresses and defense responses. Previous reports showed that miR394 responded to P. infestans inoculation in potato, indicating that miR394 may be involved in defense responses. In this study, we further investigated its role in potato defense against P. infestans. Stable expression of miR394 in tobacco and potato enhances the susceptibility to P. infestans, which is accompanied with the reduced accumulation of ROS and down-regulation of the PTI (pattern-triggered immunity) marker genes. Besides well-known target StLCR, miR394 also targets StA/N-INVE, which encodes a chloroplast Alkaline/Neutral Invertases (A/N-INVE). Both StLCR and StA/N-INVE positively regulate late blight resistance, while miR394 degrades them. Interestingly, StA/N-INVE is located in the chloroplast, indicating that miR394 may manipulate chloroplast immunity. Degradation of StA/N-INVE may affect the chloroplast function and hence lead to the compromised ROS (reactive oxygen species) burst and reduced retrograde signaling from the chloroplast to the nucleus and cytoplasm. In summary, this study provides new information that miR394 targets and degrades StA/N-INVE and StLCR, which are positive regulators, to enhance potato susceptibility to P. infestans.

[Identification and functional analysis of jasmonic acid signaling repressor McJAZ8 gene in Mentha canadensis].

Mentha canadensis, as a plant with medicinal and culinary uses, holds significant economic value. Jasmonic acid signaling repressor JAZ protein has a crucial role in regulating plant response to adversity stresses. The M. canadensis McJAZ8 gene is cloned and analyzed for protein characterization, protein interactions, and expression patterns, so as to provide genetic resources for molecular breeding of M. canadensis for stress tolerance. This experiment will analyze the protein structural characteristics, subcellular localization, protein interactions, and gene expression of McJAZ8 using bioinformatics, yeast two-hybrid(Y2H), transient expression in tobacco leaves, qRT-PCR, and other technologies. The results show that:(1)The full length of the McJAZ8 gene is 543 bp, encoding 180 amino acids. The McJAZ8 protein contains conserved TIFY and Jas domains and exhibits high homology with Arabidopsis thaliana AtJAZ1 and AtJAZ2.(2)The McJAZ8 protein is localized in the nucleus and cytoplasm.(3)The Y2H results show that McJAZ8 interacts with itself or McJAZ1/3/4/5 proteins to form homologous or heterologous dimers.(4)McJAZ8 is expressed in different tissue, with the highest expression level in young leaves. In terms of leaf sequence, McJAZ8 shows the highest expression level in the fourth leaf and the lowest expression level in the second leaf.(5) In leaves and roots, the expression of McJAZ8 is upregulated to varying degrees under methyl jasmonate(MeJA), drought, and NaCl treatments. The expression of McJAZ8 shows an initial upregulation followed by a downregulation pattern under CdCl_2 treatment. In leaves, the expression of McJAZ8 tends to gradually decrease under CuCl_2 treatment, while in roots, it initially decreases and then increases before decreasing again. In both leaves and roots, the expression of McJAZ8 is downregulated to varying degrees under AlCl_(3 )treatment. This study has enriched the research on jasmonic acid signaling repressor JAZ genes in M. canadensis and provided genetic resources for the molecular breeding of M. canadensis.

[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.

Integrated transcriptome and metabolome analysis provide insights into the mechanism of saponin biosynthesis and its role in alleviating cadmium-induced oxidative damage in Ophiopogon japonicum.

Zhe-Maidong, a cultivar of Ophiopogon japonicus is a prominent traditional herbal medicine rich in saponins. This study explored the mechanism of saponin biosynthesis and its role in alleviating Cd-induced oxidative damage in the Zhe-Maidong cultivar using three experimental groups undergoing Cd stress. In the Cd-contaminated soil treatment, total saponins were 1.68 times higher than those in the control. The saponin content in the Cd-2 and Cd-3 treatments was approximately twice as high as that in the Cd-CK treatment. These findings revealed that Cd stress leads to total saponin accumulation. Metabolomic analysis identified the accumulated saponins, primarily several monoterpenoids, diterpenoids, and triterpenoids. The increased saponins exhibited an antioxidant ability to prevent the accumulation of Cd-induced reactive oxygen species (ROS). Subsequent saponin application experiments provided strong evidence that saponin played a crucial role in promoting superoxide dismutase (SOD) activity and reducing ROS accumulation. Transcriptome analysis revealed vital genes for saponin synthesis under Cd stress, including SE, two SSs, and six CYP450s, positively correlated with differentially expressed metabolite (DEM) levels in the saponin metabolic pathway. Additionally, the TF-gene regulatory network demonstrated that bHLH1, bHLH3, mTERF, and AUX/IAA transcript factors are crucial regulators of hub genes involved in saponin synthesis. These findings significantly contribute to our understanding of the regulatory network of saponin synthesis and its role in reducing oxidative damage in O. japonicum when exposed to Cd stress.

[Cloning and functional analysis of AcFMO from onion during alliine biosynthesis].

Flavin-containing monooxygenase (FMO) is the key enzyme in the biosynthesis pathway of CSOs with sulfur oxidation. In order to explore the molecular regulatory mechanism of FMO in the synthesis of onion CSOs, based on transcriptome database and phylogenetic analysis, one AcFMO gene that may be involved in alliin synthesis was obtained, the AcFMO had a cDNA of 1 374 bp and encoded 457 amino acids, which was evolutionarily closest to the AsFMO of garlic. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) indicated that AcFMO was the highest in the flowers and the lowest in the leaf sheaths. The results of subcellular localization showed that the AcFMO gene product was widely distributed throughout the cell A yeast expression vector was constructed, and the AcFMO gene was ecotopically overexpressed in yeast to further study the enzyme function in vitro and could catalyze the synthesis of alliin by S-allyl-l-cysteine. In summary, the cloning and functional identification of AcFMO have important reference value for understanding the biosynthesis of CSOs in onions.

Litchi pulp-derived gamma-aminobutyric acid (GABA) extract counteracts liver inflammation induced by litchi thaumatin-like protein.

Gamma-aminobutyric acid (GABA) is the predominant amino acid in litchi pulp, known for its neuroregulatory effects and anti-inflammatory properties. Although previous research has highlighted the pro-inflammatory characteristics of litchi thaumatin-like protein (LcTLP), interplay between GABA and LcTLP in relation to inflammation remains unclear. This study aims to explore the hepatoprotective effects of the litchi pulp-derived GABA extract (LGE) against LcTLP-induced liver inflammation in mice and LO2 cells. In vivo experiments demonstrated that LGE significantly reduced the levels of aspartate transaminase and alanine transaminase, and protected the liver against infiltration of CD4+ and CD8+ T cells and histological injury induced by LcTLP. Pro-inflammatory cytokines including interleukin-6, interleukin-1ß, and tumor necrosis factor-α were also diminished by LGE. The LGE appeared to modulate the mitogen-activated protein kinase (MAPK) signaling pathway to exert its anti-inflammatory effects, as evidenced by a reduction of 47%, 35%, and 31% in phosphorylated p38, JNK, and ERK expressions, respectively, in the liver of the high-dose LGE group. Additionally, LGE effectively improved the translocation of gut microbiota by modulating its microbiological composition and abundance. In vitro studies have shown that LGE effectively counteracts the increase in reactive oxygen species, calcium ions, and pro-inflammatory cytokines induced by LcTLP. These findings may offer new perspectives on the health benefits and safety of litchi consumption.

Molecular mechanisms of self-incompatibility in Brassicaceae and Solanaceae.

Self-incompatibility (SI) is a mechanism for preventing self-fertilization in flowering plants. SI is controlled by a single S-locus with multiple haplotypes (S-haplotypes). When the pistil and pollen share the same S-haplotype, the pollen is recognized as self and rejected by the pistil. This review introduces our research on Brassicaceae and Solanaceae SI systems to identify the S-determinants encoded at the S-locus and uncover the mechanisms of self/nonself-discrimination and pollen rejection. The recognition mechanisms of SI systems differ between these families. A self-recognition system is adopted by Brassicaceae, whereas a collaborative nonself-recognition system is used by Solanaceae. Work by our group and subsequent studies indicate that plants have evolved diverse SI systems.

Genome-wide investigation of UDP-Glycosyltransferase family in Tartary buckwheat (Fagopyrum tataricum).

BACKGROUND: Tartary buckwheat (Fagopyrum tataricum) belongs to Polygonaceae family and has attracted increasing attention owing to its high nutritional value. UDP-glycosyltransferases (UGTs) glycosylate a variety of plant secondary metabolites to control many metabolic processes during plant growth and development. However, there have been no systematic reports of UGT superfamily in F. tataricum. RESULTS: We identified 173 FtUGTs in F. tataricum based on their conserved UDPGT domain. Phylogenetic analysis of FtUGTs with 73 Arabidopsis UGTs clustered them into 21 families. FtUGTs from the same family usually had similar gene structure and motif compositions. Most of FtUGTs did not contain introns or had only one intron. Tandem repeats contributed more to FtUGTs amplification than segmental duplications. Expression analysis indicates that FtUGTs are widely expressed in various tissues and likely play important roles in plant growth and development. The gene expression analysis response to different abiotic stresses showed that some FtUGTs were involved in response to drought and cadmium stress. Our study provides useful information on the UGTs in F. tataricum, and will facilitate their further study to better understand their function. CONCLUSIONS: Our results provide a theoretical basis for further exploration of the functional characteristics of FtUGTs and for understanding the growth, development, and metabolic model in F. tataricum.

Alternative splicing of CsWRKY21 positively regulates cold response in tea plant.

Alternative splicing (AS) was an important post-transcriptional mechanism that involved in plant resistance to adversity stress. WRKY transcription factors function as transcriptional activators or repressors to modulate plant growth, development and stress response. However, the role of alternate splicing of WRKY in cold tolerance is poorly understood in tea plants. In this study, we found that the CsWRKY21 transcription factor, a member of the WRKY IId subfamily, was induced by low temperature. Subcellular localization and transcriptional activity assays showed that CsWRKY21 localized to the nucleus and had no transcriptional activation activity. Y1H and dual-luciferase reporter assays showed that CsWRKY21 suppressed expression of CsABA8H and CsUGT by binding with their promoters. Transient overexpression of CsABA8H and CsUGT reduced abscisic acid (ABA) content in tobacco leaves. Furthermore, we discovered that CsWRKY21 undergoes AS in the 5'UTR region. The AS transcript CsWRKY21-b was induced at low temperature, up to 6 folds compared to the control, while the full-length CsWRKY21-a transcript did not significantly change. Western blot analysis showed that the retention of introns in the 5'UTR region of CsWRKY21-b led to higher CsWRKY21 protein content. These results revealed that alternative splicing of CsWRKY21 involved in cold tolerance of tea plant by regulating the protein expression level and then regulating the content of ABA, and provide insights into molecular mechanisms of low temperature defense mediated by AS in tea plant.

Exo84c-regulated degradation is involved in the normal self-incompatible response in Brassicaceae.

The self-incompatibility system evolves in angiosperms to promote cross-pollination by rejecting self-pollination. Here, we show the involvement of Exo84c in the SI response of both Brassica napus and Arabidopsis. The expression of Exo84c is specifically elevated in stigma during the SI response. Knocking out Exo84c in B. napus and SI Arabidopsis partially breaks down the SI response. The SI response inhibits both the protein secretion in papillae and the recruitment of the exocyst complex to the pollen-pistil contact sites. Interestingly, these processes can be partially restored in exo84c SI Arabidopsis. After incompatible pollination, the turnover of the exocyst-labeled compartment is enhanced in papillae. However, this process is perturbed in exo84c SI Arabidopsis. Taken together, our results suggest that Exo84c regulates the exocyst complex vacuolar degradation during the SI response. This process is likely independent of the known SI pathway in Brassicaceae to secure the SI response.

Identification of calcium chelating peptides from peanut protein hydrolysate and absorption activity of peptide-calcium complex.

BACKGROUND: Peanut peptides have good chelating ability with metal ions. However, there are few studies on the chelation mechanism of peanut peptides with calcium and absorption properties of peptide-calcium complex. RESULTS: Peptides with high calcium chelating rate were isolated and purified from peanut protein hydrolysate (PPH), and the chelation rate of component F21 was higher (81.4 ± 0.8%). Six peptides were identified from component F21 by liquid chromatography-tandem mass spectrometry, and the frequency of acidic amino acids and arginine in the amino acid sequence was higher in all six peptides. Peanut peptide-calcium complex (PPH21-Ca) was prepared by selecting component F21 (PPH21). Ultraviolet analysis indicated that the chelate reaction occurred between peanut peptide and calcium ions. Fourier transform infrared analysis showed that the chelating sites were carboxyl and amino groups on the amino acid residues of peptides. Scanning electron microscopy revealed that the surface of peanut peptide had a smooth block structure, but the surface of the complex had a granular morphology. Caco-2 cell model tests revealed that the bioavailability of PPH21-Ca was 58.4 ± 0.5%, which was significantly higher than that of inorganic calcium at 37.0 ± 0.4%. CONCLUSION: Peanut peptides can chelate calcium ions by carboxyl and amino groups, and the peptide-calcium complex had higher bioavailability. This study provides a theoretical basis for the development of new calcium supplement products that are absorbed easily. © 2024 Society of Chemical Industry.

CsREV-CsTCP4-CsVND7 module shapes xylem patterns differentially between stem and leaf to enhance tea plant tolerance to drought.

Cultivating drought-tolerant tea varieties enhances both yield and quality of tea plants in northern China. However, the mechanisms underlying their drought tolerance remain largely unknown. Here we identified a key regulator called CsREV, which differentially regulates xylem patterns between leaves and stems, thereby conferring drought tolerance in tea plants. When drought occurs, upregulation of CsREV activates the CsVND7a-dependent xylem vessel differentiation. However, when drought persists, the vessel differentiation is hindered as CsVND7a is downregulated by CsTCP4a. This, combined with the CsREV-promoted secondary-cell-wall thickness of xylem vessel, leads to the enhanced curling of leaves, a characteristic closely associated with plant drought tolerance. Notably, this inhibitory effect of CsTCP4a on CsVND7a expression is absent in stems, allowing stem xylem vessels to continuously differentiate. Overall, the CsREV-CsTCP4-CsVND7 module is differentially utilized to shape the xylem patterns in leaves and stems, potentially balancing water transportation and utilization to improve tea plant drought tolerance.

Gene expression analysis of potato drought-responsive genes under drought stress in potato (Solanum tuberosum L.) cultivars.

The potato (Solanum tuberosum L.), an important field crop consumed extensively worldwide, is adversely affected by abiotic stress factors especially drought. Therefore, it is vital to understand the genetic mechanism under drought stress to decrease loose of yield and quality . This trial aimed to screen drought-responsive gene expressions of potato and determine the drought-tolerant potato cultivar. The trial pattern is a completely randomized block design (CRBD) with four replications under greenhouse conditions. Four cultivars (Brooke, Orwell, Vr808, Shc909) were irrigated with four different water regimes (control and three stress conditions), and the gene expression levels of 10 potato genes were investigated. The stress treatments as follows: Control = 100% field capacity; slight drought = 75% field capacity; moderate drought = 50% field capacity, and severe drought 25% field capacity. To understand the gene expression under drought stress in potato genotypes, RT-qPCR analysis was performed and results showed that the genes most associated with drought tolerance were the StRD22 gene, MYB domain transcription factor, StERD7, Sucrose Synthase (SuSy), ABC Transporter, and StDHN1. The StHSP100 gene had the lowest genetic expression in all cultivars. Among the cultivars, the Orwell exhibited the highest expression of the StRD22 gene under drought stress. Overall, the cultivar with the highest gene expression was the Vr808, closely followed by the Brooke cultivar. As a result, it was determined that potato cultivars Orwell, Vr808, and Brooke could be used as parents in breeding programs to develop drought tolerant potato cultivars.

Genome-Wide Identification and Analysis of the Aux/IAA Gene Family in Panax ginseng: Evidence for the Role of PgIAA02 in Lateral Root Development.

Panax ginseng C. A. Meyer (Ginseng) is one of the most used traditional Chinese herbal medicines, with its roots being used as the main common medicinal parts; its therapeutic potential has garnered significant attention. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) is a family of early auxin-responsive genes capable of regulating root development in plants through the auxin signaling pathway. In the present study, 84 Aux/IAA genes were identified from the ginseng genome and their complexity and diversity were determined through their protein domains, phylogenetic relationships, gene structures, and cis-acting element predictions. Phylogenetic analyses classified PgIAA into six subgroups, with members in the same group showing greater sequence similarity. Analyses of interspecific collinearity suggest that segmental duplications likely drove the evolution of PgIAA genes, followed by purifying selection. An analysis of cis-regulatory elements suggested that PgIAA family genes may be involved in the regulation of plant hormones. RNA-seq data show that the expression pattern of Aux/IAA genes in Ginseng is tissue-specific, and PgIAA02 and PgIAA36 are specifically highly expressed in lateral, fibrous, and arm roots, suggesting their potential function in root development. The PgIAA02 overexpression lines exhibited an inhibition of lateral root growth in Ginseng. In addition, yeast two-hybrid and subcellular localization experiments showed that PgIAA02 interacted with PgARF22/PgARF36 (ARF: auxin response factor) in the nucleus and participated in the biological process of root development. The above results lay the foundation for an in-depth study of Aux/IAA and provide preliminary information for further research on the role of the Aux/IAA gene family in the root development of Ginseng.

Genome-Wide Identification of LOX Gene Family and Its Expression Analysis under Abiotic Stress in Potato (Solanum tuberosum L.).

The lipoxygenases (LOXs) are non-heme iron-containing dioxygenases that play an important role in plant growth and defense responses. There is scarce knowledge regarding the LOX gene family members and their involvement in biotic and abiotic stresses in potato. In this study, a total of 17 gene family members (StLOXs) in potato were identified and clustered into three subfamilies: 9-LOX type I, 13-LOX type I, and 13-LOX type II, with eleven, one, and five members in each subfamily based on phylogenetic analysis. By exploiting the RNA-seq data in the Potato Genome Sequencing Consortium (PGSC) database, the tissue-specific expressed and stress-responsive StLOX genes in double-monoploid (DM) potato were obtained. Furthermore, six candidate StLOX genes that might participate in drought and salt response were determined via qPCR analysis in tetraploid potato cultivars under NaCl and PEG treatment. Finally, the involvement in salt stress response of two StLOX genes, which were significantly up-regulated in both DM and tetraploid potato under NaCl and PEG treatment, was confirmed via heterologous expression in yeast under salt treatment. Our comprehensive analysis of the StLOX family provides a theoretical basis for the potential biological functions of StLOXs in the adaptation mechanisms of potato to stress conditions.