Xanthoceras Research Articles

Genetic diversity analysis of phenotypic traits among 37 Xanthoceras sorbifolium elite germplasms

ABSTRACT Xanthoceras sorbifolium is one of the most economically important species cultivated in northern China. To analyze the phenotypic variation within X. sorbifolium, 35 phenotypic traits among 37 elite germplasms were analyzed using nested analysis of variance, coefficient of variation (CVs), principal component analysis (PCA), correlation analysis, and cluster analysis. Large variation and rich phenotypic diversity were found among and within germplasms of X. sorbifolium. The mean of coefficient of variation for 35 traits among 37 germplasms was 25.49%. It varied from 12.80% to 63.25%, and ranked as follows: branch traits (45.51%) > inflorescence traits (31.01%) > fruit traits (24.67%) > flower traits (24.35%) > seed traits (21.82%) > leaf traits (21.45%). The mean heritability (H2) of 35 phenotypic traits was 75.94%. Significant correlations were observed within and among most branch, leaf, inflorescence, flower, fruit, and seed traits. The cumulative contribution rate of the first nine main principle components reached 80.333%. The 35 phenotypic traits were classified into two main categories and five subcategories by clustering analysis of phenotypic traits. Combined result of correlation, PCA, and clustering of phenotypic traits, 18 representative traits were selected. The 37 elite germplasms were classified into two main groups and six subgroups according to their characteristics by Ward’s method and reasonable utilization of each subgroup were suggested. These results provide useful information for genetic improvement, preservation, and evaluation of X. sorbifolium germplasms.

A RARE CASE OF HARLEQUIN ICHTHYOSIS SUCCESSFULLY TREATED WITH ACITRETIN: A CASE REPORT AND LITERATURE REVIEW

Harlequin Ichthyosis is the most serious congenital keratinization disorder. When the children are born, they are enveloped in thick horn armor. They are thick yellow horn plates that tear deeply when they dry out. In the most severe form, the children often die in the first few weeks of life. But there are also many milder courses, whereby there are obviously flowing transitions from collodion baby to harlequin ichthyosis. The skin condition later corresponds to that of a child with severe congenital ichthyosis (ARCI). Similar to the collodion baby, cases of harlequin ichthyosis should initially be cared for in the intensive care unit for newborns and require interdisciplinary therapy. Harlequin ichthyosis is caused by very special mutations in the ABCA12 gene. These mutations also have an impact on survival. If homozygous mutations are present, the prospects are worse than if the parents have heterozygous mutations. Homozygous mutations are often present when the parents are consanguineous.

Centromere-Specific Retrotransposons and Very-Long-Chain Fatty Acid Biosynthesis in the Genome of Yellowhorn (Xanthoceras sorbifolium, Sapindaceae), an Oil-Producing Tree With Significant Drought Resistance.

In-depth genome characterization is still lacking for most of biofuel crops, especially for centromeres, which play a fundamental role during nuclear division and in the maintenance of genome stability. This study applied long-read sequencing technologies to assemble a highly contiguous genome for yellowhorn (Xanthoceras sorbifolium), an oil-producing tree, and conducted extensive comparative analyses to understand centromere structure and evolution, and fatty acid biosynthesis. We produced a reference-level genome of yellowhorn, ∼470 Mb in length with ∼95% of contigs anchored onto 15 chromosomes. Genome annotation identified 22,049 protein-coding genes and 65.7% of the genome sequence as repetitive elements. Long terminal repeat retrotransposons (LTR-RTs) account for ∼30% of the yellowhorn genome, which is maintained by a moderate birth rate and a low removal rate. We identified the centromeric regions on each chromosome and found enrichment of centromere-specific retrotransposons of LINE1 and Gypsy in these regions, which have evolved recently (∼0.7 MYA). We compared the genomes of three cultivars and found frequent inversions. We analyzed the transcriptomes from different tissues and identified the candidate genes involved in very-long-chain fatty acid biosynthesis and their expression profiles. Collinear block analysis showed that yellowhorn shared the gamma (γ) hexaploidy event with Vitis vinifera but did not undergo any further whole-genome duplication. This study provides excellent genomic resources for understanding centromere structure and evolution and for functional studies in this important oil-producing plant.

The yellowhorn AGL transcription factor gene XsAGL22 contributes to ABA biosynthesis and drought tolerance in poplar.

Regulation of abscisic acid (ABA) biosynthesis helps plants adapt to drought stress, but the underlying molecular mechanisms are largely unclear. Here, a drought-induced transcription factor XsAGL22 was isolated from yellowhorn (Xanthoceras sorbifolium Bunge). Yeast one-hybrid and electrophoretic mobility shift assays indicated that XsAGL22 can physically bind to the promoters of the ABA biosynthesis-related genes XsNCED6 and XsBG1, and a dual-luciferase assay showed that XsAGL22 activates the promoters of the later two genes. Transient overexpression of XsAGL22 in yellowhorn leaves also increased the expression of XsNCED6 and XsBG1 and increased cellular ABA levels. Finally, heterologous overexpression of XsAGL22 in poplar increased ABA content, reduced stomatal aperture and increased drought resistance. Our results suggest that XsAGL22 is a powerful regulator of ABA biosynthesis and plays a critical role in drought resistance in plants.

Switch from symplasmic to aspoplasmic phloem unloading in Xanthoceras sorbifolia fruit and sucrose influx XsSWEET10 as a key candidate for Sugar transport

The process of phloem unloading and post-unloading transport of photoassimilate is critical to crop output. Xanthoceras sorbifolia is a woody oil species with great biomass energy prospects in China; however, underproduction of seeds seriously restricts its development. Here, our cytological studies by ultrastructural observation revealed that the sieve element-companion cell complex in carpellary bundle was symplasmically interconnected with surrounding parenchyma cells at the early and late fruit developmental stages, whereas it was symplasmically isolated at middle stage. Consistently, real-time imaging showed that fluorescent tracer 6(5)carboxyfluorescein was confined to phloem strands at middle stage but released into surrounding parenchymal cells at early and late stages. Enzymatic assay showed that sucrose synthase act as the key enzyme catalyzing the progress of Suc degradation post-unloading pathway whether in pericarp or in seed, while vacuolar acid invertase and neutral invertase play compensation roles in sucrose decomposition. Sugar transporter XsSWEET10 had a high expression profile in fruit, especially at middle stage. XsSWEET10 is a plasma membrane-localized protein and heterologous expression in SUC2-deficient yeast strain SUSY7/ura3 confirmed its ability to uptake sucrose. These findings approved the transition from symplasmic to apoplasmic phloem unloading in Xanthoceras sorbifolia fruit and XsSWEET10 as a key candidate in sugar transport.

Small RNA profiling for identification of microRNAs involved in regulation of seed development and lipid biosynthesis in yellowhorn

BackgroundYellowhorn (Xanthoceras sorbifolium), an endemic woody oil-bearing tree, has become economically important and is widely cultivated in northern China for bioactive oil production. However, the regulatory mechanisms of seed development and lipid biosynthesis affecting oil production in yellowhorn are still elusive. MicroRNAs (miRNAs) play crucial roles in diverse aspects of biological and metabolic processes in seeds, especially in seed development and lipid metabolism. It is still unknown how the miRNAs regulate the seed development and lipid biosynthesis in yellowhorn.ResultsHere, based on investigations of differences in the seed growth tendency and embryo oil content between high-oil-content and low-oil-content lines, we constructed small RNA libraries from yellowhorn embryos at four seed development stages of the two lines and then profiled small RNA expression using high-throughput sequencing. A total of 249 known miRNAs from 46 families and 88 novel miRNAs were identified. Furthermore, by pairwise comparisons among the four seed development stages in each line, we found that 64 miRNAs (53 known and 11 novel miRNAs) were differentially expressed in the two lines. Across the two lines, 15, 11, 10, and 7 differentially expressed miRNAs were detected at 40, 54, 68, and 81 days after anthesis, respectively. Bioinformatic analysis was used to predict a total of 2654 target genes for 141 differentially expressed miRNAs (120 known and 21 novel miRNAs). Most of these genes were involved in the fatty acid biosynthetic process, regulation of transcription, nucleus, and response to auxin. Using quantitative real-time PCR and an integrated analysis of miRNA and mRNA expression, miRNA-target regulatory modules that may be involved in yellowhorn seed size, weight, and lipid biosynthesis were identified, such as miR172b-ARF2 (auxin response factor 2), miR7760-p3_1-AGL61 (AGAMOUS-LIKE 61), miR319p_1-FAD2–2 (omega-6 fatty acid desaturase 2–2), miR5647-p3_1-DGAT1 (diacylglycerol acyltransferase 1), and miR7760-p5_1-MED15A (Mediator subunit 15a).ConclusionsThis study provides new insights into the important regulatory roles of miRNAs in the seed development and lipid biosynthesis in yellowhorn. Our results will be valuable for dissecting the post-transcriptional and transcriptional regulation of seed development and lipid biosynthesis, as well as improving yellowhorn in northern China.

Growth, Physiological, and Photosynthetic Responses of Xanthoceras sorbifolium Bunge Seedlings Under Various Degrees of Salinity.

Xanthoceras sorbifolium Bunge is priced for its medical and energetic values. The species also plays a key role in stabilizing ecologically fragile areas exposed to excess soil salinity. In this study, the effects of salinity on the growth, physiological, and photosynthetic parameters of X. sorbifolium Bunge were investigated. The X. sorbifolium seedlings were subjected to five salt treatments: 0 (control, CK), 70, 140, 210, and 280 mM of sodium chloride (NaCl) solutions. NaCl caused a decrease in plant height, specific leaf area, biomass, and root parameters. Leaf wilting and shedding and changes in root morphology, such as root length, root surface area, and root tips were observed. This study found that X. sorbifolium is tolerant to high salinity. Compared with the CK group, even if the concentration of NaCl was higher than 210 mM, the increase of the relative conductivity was also slow, while intercellular CO2 concentration had a similar trend. Moreover, NaCl stress caused an increase in the malondialdehyde (MDA), soluble proteins, and proline. Among the enzymes in the plant, the catalase (CAT) activity increases first and decreased with the increase in the intensity of NaCl stress, but the salt treatment had no significant effect on superoxide dismutase (SOD) activity. The peroxidase (POD) showed an increasing trend under salt stress. It was found that the photosynthesis of X. sorbifolium was notably impacted by saline stress. NaCl toxicity induced a noticeable influence on leaf net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (E), and water use efficiency (Wue). As salt concentration increased, the content of chlorophyll decreased. It can be found that a low concentration of NaCl induced the increase of photosynthetic capacity but a high-intensity exposure to stress resulted in the reduction of photosynthetic efficiency and SOD activity, which had a positive correlation. In summary, salt-induced ionic stress primarily controlled root morphology, osmotic adjustment, and enzyme activities of salt-treated X. sorbifolium leaves, whereas the low salt load could, in fact, promote the growth of roots.

Potential Suitable Habitat of Two Economically Important Forest Trees (Acer truncatum and Xanthoceras sorbifolium) in East Asia under Current and Future Climate Scenarios

Acer truncatum Bunge and Xanthoceras sorbifolium Bunge are small deciduous trees distributed in East Asia and have high ecological and nutrient value due to their strong environmental adaptability and seed oil abundant in nervonic acid and unsaturated fatty acids. However, their natural distribution remains unclear, which will also be affected by the changing climatic conditions. The main purpose of this study was to map and predict the current and future potential suitable habitats of these two species using MaxEnt based on the presence location of species and environmental variables. The results showed that A. truncatum was more suitable for warm and humid climates and was more durable to climate change compared to X. sorbifolium. Under the current environmental conditions, the suitable habitat of A. truncatum was mainly concentrated in Inner Mongolia Plateau, Loess Plateau, Sichuan Basin, Northeast Plain, North China Plain, Korean Peninsula, as well as Japan, with an area of 115.39 × 104 km2. X. sorbifolium was mainly distributed in Inner Mongolia Plateau and Loess Plateau with an area of 146.15 × 104 km2. Under future climate scenarios, the model predicted that higher concentrations of greenhouse gas emissions could result in greater expansion of the potential distribution of both species. Meanwhile, the study also revealed that the two species migrated to the north by east to varying degrees with the change in suitable habitats. This work could provide scientific basis for resource protection and utilization of the two economic forest trees.

Progress in research and development of Xanthoceras sorbifolia

Xanthoceras sorbifolia, an excellent oil-rich woody species, has high comprehensive economic value in edible, medicinal, and ornamental fields. The chemical composition, pharmacological effect, and quality control of X. sorbifolia were introduced, and its development and application were reviewed in this study. As revealed by the previous research, the main chemical constituents of X. sorbifolia were triterpenoids, flavonoids, fatty acids, phenylpropanoids, steroids, phenolic acids, organic acids, etc. It possesses pharmacological effects, such as neuroprotection, bacteriostasis, anti-oxidation, anti-tumor, anti-inflammation, analgesia, anti-HIV, and anti-coagulation. X. sorbifolia is widely applied in medical, food, chemical industry, and other fields, and deserves in-depth research and development.

Xanthoceras sorbifolium Bunge: A Review on Botany, Phytochemistry, Pharmacology, and Applications.

Xanthoceras sorbifolium Bunge (Sapindaceae) is a native Chinese plant with promising applications as a biofuel feedstock and a source of novel drugs. Historical records and documents from different periods have mentioned the use of X. sorbifolium and its botanical constituents in treating diseases, highlighting its central role in Chinese and Mongolian traditional medicinal therapies. Phytochemical research has focused on the husks, leaves, trunks, and branches of this herb. A total of 278 chemical compounds have been isolated and divided into 8 categories: triterpenoids, flavonoids, phenylpropanoids, steroids, phenols, fatty acids, alkaloids, and quinones. Modern pharmacological studies on X. sorbifolium have demonstrated positive effects on learning and memory, as well as anti-inflammatory, anti-tumor, and anti-oxidative properties. This review provides a comprehensive analysis of the available research on X. sorbifolium, focusing on the relationship between chemical constituents, traditional uses, and pharmacological effects. We also assess the potential for therapeutic and other applications of this plant in support of further research and development of X. sorbifolium.

Optimization of one-step production of biodiesel by Sulfuric acid/Stannic oxide-Hangjin2 clay catalyzed xanthoceras sorbifolia bunge kernel

ABSTRACT In this study, biodiesel has been successfully prepared from Xanthoceras sorbifolia seed kernel by SO4 2-/SnO2-Hangjin2#clay as catalyst. Based on the Central Composite Design method, the effect of the various parameters influencing the biodiesel process have been studied and optimized. The maximum yield of biodiesel (90.67%w/w) can be obtained when the mass fraction of the catalyst is 0.7%, the mass ratio of methanol to oil is 4:1 V/m, the methanol content in the oil is 12%, and the reaction temperature achieves 81°C。Besides, the consequence of Infrared spectroscopy and Gas chromatography can assure the production of biodiesel from the xanthoceras sorbifolia bunge oil. Based on these results, it can be concluded that Xanthoceras sorbifolia bunge seed oil is an acceptable non-edible feedstock for biodiesel production.

Simultaneous quantification of five bioactive 16-deoxybarringtogenol C triterpenoid saponins in rat plasma by HPLC-MS: Application to a pharmacokinetic study after oral administration of Xanthoceras sorbifolia Bunge husks extract

AbstractIn this study, a simple and rapid liquid chromatography-mass spectrometry method was developed to simultaneously determinate five 16-deoxybarringtogenol C triterpenoid saponins with the potential of neuroprotection in rat plasma following the oral administration of the Xanthoceras sorbifolia Bunge husks extract. With digoxin as the internal standard, the plasma samples were pre-treated by ethyl acetate-isopropanol (1:1, v/v). The chromatographic separation of the five analytes was performed using a Phenomenex C18 column (250 mm × 4.6 mm, 5.0 mm) with a mobile phase of 0.05% formic acid (A)-acetonitrile (B). The mass spectrometric detection was carried out in the selected ion mode in positive ionization. The extraction recoveries of the five analytes were all over 71.28%. The established method was fully validated in line with the ICH and Food and Drug Administration (FDA) guidelines and successfully applied to the pharmacokinetic study on the five analytes in rat plasma. The terminal half-life (t1/2) of the five analytes was 2.92 ± 0.57, 5.52 ± 1.75, 2.48 ± 0.62, 2.95 ± 0.94, and 2.34 ± 0.81, respectively. This study was purposed to investigate the oral pharmacokinetic parameters and gain an in-depth insight into the reasonable preclinical use of the husks extract derived from X. sorbifolia Bunge.

Xanthoceraside administration produces significant antidepressant effects in mice through activation of the hippocampal BDNF signaling pathway

Current available antidepressants have various adverse reactions and slow pharmacodynamics, so it is necessary to find novel antidepressants for effective treatment. Xanthoceraside (XAN), a novel triterpenoid saponin extracted from the fruit husks of Xanthoceras sorbifolium Bunge, has anti-amnesic and neuroprotective properties. The purpose and significance of this study is to assess whether XAN has antidepressant effects in mice using the forced swim test (FST), tail suspension test (TST) and chronic unpredictable mild stress (CUMS) model of depression. The effects of XAN treatment on the hippocampal brain-derived neurotrophic factor (BDNF) signaling pathway and neurogenesis were examined. The antidepressant mechanism of XAN was explored using a BDNF inhibitor (K252a) and an anti-BDNF antibody. It was found that XAN administration significantly reversed the depressive-like behaviors of CUMS-treated mice. XAN treatment also significantly prevented the decreasing effects of CUMS on the hippocampal BDNF signaling and neurogenesis. The antidepressant effects of XAN in mice were blocked by both administration of K252a and anti-BDNF antibody. Collectively, these findings indicate that XAN possesses antidepressant effects in mice which are mediated by activation of hippocampal BDNF signaling pathway, thus providing the first evidence that XAN can be a potential antidepressant candidate.

Nervonic acid amends motor disorder in a mouse model of Parkinson's disease.

ObjectivesParkinson’s disease (PD) is a kind of common neurodegenerative disease in the world. Previous studies have proved that nervonic acid (NA), extracted from Xanthoceras sorbifolia Bunge, has the potentials of neuroprotection. However, the effect of NA on the PD remained unknown. This study was designed to investigate the NA’s potential function and relative mechanism on motor disorder.Methods1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was used for producing parkinsonism motor disorder on male C57BL/6 mice. Toxicity experiments and behavioral assay were performed to evaluate the effect of NA. Besides, the expression levels of tyrosine hydroxylase and α-synuclein, as well as striatal dopamine (DA), serotonin, and their metabolites were explored through immunoblotting and chromatography after NA treatment in vivo.ResultsWe found that NA could alleviate the MPTP-induced behavioral deficits dose-dependently. Moreover, NA has no toxic effects on the mouse liver and kidney. Of note, we found that NA significantly reduced the impact of MPTP impairment and striatal DA, serotonin, and metabolites were remained unaffected. In addition, tyrosine hydroxylase was upregulated while α-synuclein being downregulated and the oxidative stress was partially repressed evidenced by the upregulation of superoxide dismutase and glutathione activity after NA treatment.ConclusionOur findings unveil NA’s potential for protecting motor system against motor disorder in the PD mouse model without any side effects, indicating NA as an alternative strategy for PD symptom remission.

Analysis of the nutritional components in the kernels of yellowhorn (Xanthoceras sorbifolium Bunge) accessions

The oilseed tree species yellowhorn (Xanthoceras sorbifolium Bunge) is a promising oil crop; however, the nutritional properties of the kernels have not been adequately explored. This study investigated the nutritional components of the kernels of seven yellowhorn accessions using gas chromatography and high-performance liquid chromatography. The results showed significant variations in the content of nutritional components detected in the analyzed samples. On average, the kernel oil content was 54.8 g/100 g, and 19 fatty acids were detected. The content of nervonic acid, a relatively rare fatty acid that is indispensable for nervous system development, was 3.80 %. The total concentrations of the eight phytosterols and four tocopherol homologues detected herein were 182.4 and 24.3 mg/100 g, respectively. β-Sitosterol and Δ7-stigmastenol were the most dominant phytosterols, whereas γ-tocopherol was the prevalent homologue of tocopherol. The contents of vitamin A and vitamin C in yellowhorn oil were reported for the first time in this study and were 0.133 and 0.277 mg/100 g, respectively. The total protein content, including that of the 18 detected amino acids, was 26.2 g/100 g. Principal component analysis grouped the accessions into those with high nervonic acid and phytosterol contents, high vitamin C content, high oil and oleic acid content, and moderate levels of the tested compounds.

Genome-Wide Identification and Characterization of Yellow Horn (Xanthoceras sorbifolia Bunge) NAC Transcription Factor Gene Family against Diverse Abiotic Stresses

Yellow horn (Xanthoceras sorbifolia Bunge) belonging to the Sapindaceae family is a well-known oil-rich seed shrub widely distributed throughout the northern regions of China, which is preferred owing to its exceptional economic, environmental, ecological and ornamental value. The recent completion of yellow horn genome sequencing facilitates a genome-wide survey of yellow horn transcription factor (TF) families. Plant-specific NAC proteins represent a major TF family in regulating diverse plant biological processes at different tissues and developmental stages. However, no detailed information can be obtained concerning the yellow horn NAC (XsNAC) proteins. Given this, we performed a genome-wide survey of XsNAC gene families. In total 103 putative XsNACs genes were identified from yellow horn genome. Phylogenetic analysis performed between NAC proteins of yellow horn and Arabidopsis revealed that these XsNAC proteins can be classified into 12 subgroups. Gene structure analysis revealed that the intron number of XsNAC genes varied from 0 to 12, and most XsNAC genes had two introns. Conserved motif analysis suggested that all putative XsNAC proteins had conserved NAC domain and/or NAM domain. These predicted XsNAC genes were randomly distributed on 15 chromosomes at diverse densities, particularly on chromosome 1, chromosome 7 and chromosome 11. The cis-regulatory elements (CREs) analysis and protein-protein interaction network analysis showed that the XsNAC proteins may involve in many plant physiological and biochemical processes. Transcriptome analysis revealed that XsNAC genes had differential expression profiles in response to various abiotic stresses, implying their key roles in environmental stress responses. This work would lay solid foundation for future functional characterization of XsNAC proteins.

Evaluation of “Genotype x Environment” Interaction for Performance in the Potential Energy PlantXanthoceras sorbifoliumUnder Multi-Environment

Xanthoceras sorbifoliumBunge has attracted the attention of the world because of its potential to produce biodiesel. We tested the traits of the seedlings ofX. sorbifoliumfrom 26 natural provenances cultivated in three locations of Zhangwu (ZW), Jingbian (JB) and Anqiu (AQ), and analyzed the genotype x environment interaction by BLUP-GGE method. The results showed that the genotype effect, environmental main effect and genotype-environment interaction effect have significant influence onX. sorbifoliumgrowth in the early growth stage, and the variation of ground diameter is greater than that of tree height. The genotypes G25 with the highest yield at the early growth stage, G15 with the highest stable yield, and G9, G12 and G10 with good yield and stable yield were selected. Among them, G12 is a specific high quality genotype for ZW, G10 has the best tree height in JB and AQ, and G9 has the best ground diameter in AQ. This information can evaluate each experimental site and high-quality genotypes, and provide scientific guidance and basis for subsequent biodiesel production ofX. sorbifolium.

Role of Xanthoceras sorbifolium MYB44 in tolerance to combined drought and heat stress via modulation of stomatal closure and ROS homeostasis

Yellowhorn (Xanthoceras sorbifolium) is an important edible woody oil tree species that is endemic to China. Drought and heat stresses are factors severely limiting the high-quality development of the yellowhorn industry. Transcription factors (TFs) play critical roles in regulating the response of woody plant species to water deficit or high temperature. However, the MYB TFs that respond to combined drought and heat stress in yellowhorn remain unclear.Here, we first investigated the physiological changes in 5 yellowhorn varieties in response to combined stress treatments. We observed significant changes in antioxidant enzyme activities and photosynthesis. The Maigaiti variety yielded the best results and was selected for subsequent experiments. An R2R3-type MYB TF, designated XsMYB44, was isolated from the leaves of yellowhorn. XsMYB44 expression was strongly induced by combined stress. Suppression of XsMYB44 expression via virus-induced gene silencing weakened yellowhorn tolerance to both individual and combined drought and heat stress, and the increased susceptibility was coupled with decreased plant height, fresh weight and relative water content and inhibited stomatal closure. Moreover, compared with the individual stresses, the combined stress caused increased reactive oxygen species levels and decreased antioxidant enzyme activities and proline content in XsMYB44-silenced plants. Furthermore, the expression levels of several defense-related genes were reduced in the XsMYB44-silenced plants. Overall, we studied the physiological characteristics of 5 yellowhorn varieties, and the results demonstrated that XsMYB44 acts as a positive regulator in the yellowhorn response to combined stress by triggering stomatal closure to maintain water levels and by modulating ROS homeostasis.

Valorization of biomass waste from yellow horn (Xanthoceras sorbifolia) through the preparation of porous carbon for supercapacitors

Valorization of biomass waste from yellow horn (Xanthoceras sorbifolia) through the preparation of porous carbon for supercapacitors

Role of ethylene in the regulatory mechanism underlying the abortion of ovules after fertilization in Xanthoceras sorbifolium.

Genes related to the MAPK cascade, ethylene signaling pathway, Pi starvation response, and NAC TFs were differentially expressed between normal and abortive ovules. Receptor-mediated ethylene signal perception and transmission play an important role in regulating fruit and ovule development. Xanthoceras sorbifolium, a small to medium-sized tree endemic to northern China, is an emerging dedicated oilseed crop designed for applications in advanced biofuel, engine oil, and functional food, as well as for pharmaceutical and cosmetic applications. Despite the importance of Xanthoceras seed oil, low seed productivity has constricted commercial exploitation of the species. The abortion of developing seeds (ovules after fertilization) is a major factor limiting fruit and seed production in the plant. To increase fruit and seed yields, a better understanding of the mechanisms underlying the abortion of fertilized ovules is critical. This study revealed differences in nucellus degeneration, endosperm development, and starch grain content between normally and abnormally developing ovules after fertilization. We constructed 6 RNA-sequencing (RNA-seq) libraries from normally and abnormally developing ovules at the onset of their abortion process. Comparative transcriptome analysis between the normal and abnormal ovules identified 818 differentially expressed genes (DEGs). Among DEGs, many genes involved in mitogen-activated protein kinase (MAPK) cascades, ethylene signaling pathway, and NAC transcription factor genes showed up-regulated expression in abnormal ovules. The RNA-seq data were validated using quantitative reverse-transcription PCR. Using virus-induced gene silencing (VIGS) methods, evaluation of an ethylene receptor gene (XsERS) function indicated that the gene was closely related to early development of fruits and seeds. Based on the data presented here, we propose a model for a MAPK-ethylene signaling-NAC2 gene regulatory cascade that plays an important role in the regulation of the ovule abortion process in X. sorbifolium. The present study is imperative for understanding the mechanisms of ovule abortion after fertilization and identifying the critical genes and gene networks involved in determining the fate of ovule development.