Recent Advances in Studies of Genomic DNA Methylation and Its Involvement in Regulating Drought Stress Response in Crops.

As global arid conditions worsen and groundwater resources diminish, drought stress has emerged as a critical impediment to plant growth and development globally, notably causing declines in crop yields and even the extinction of certain cultivated species. Numerous studies on drought resistance have demonstrated that DNA methylation dynamically interacts with plant responses to drought stress by modulating gene expression and developmental processes. However, the precise mechanisms underlying these interactions remain elusive. This article consolidates the latest research on the role of DNA methylation in plant responses to drought stress across various species, focusing on methods of methylation detection, mechanisms of methylation pattern alteration (including DNA de novo methylation, DNA maintenance methylation, and DNA demethylation), and overall responses to drought conditions. While many studies have observed significant shifts in genome-wide or gene promoter methylation levels in drought-stressed plants, the identification of specific genes and pathways involved remains limited. This review aims to furnish a reference for detailed research into plant responses to drought stress through epigenetic approaches, striving to identify drought resistance genes regulated by DNA methylation, specific signaling pathways, and their molecular mechanisms of action.

Exploring the Impact of Coconut Peat and Vermiculite on the Rhizosphere Microbiome of Pre-Basic Seed Potatoes under Soilless Cultivation Conditions.

Soilless cultivation of potatoes often utilizes organic coconut peat and inorganic vermiculite as growing substrates. The unique microbial communities and physicochemical characteristics inherent to each substrate significantly influence the microecological environment crucial for potato growth and breeding. This study analyzed environmental factors within each substrate and employed Illumina sequencing alongside bioinformatics tools to examine microbial community structures, their correlation with environmental factors, core microbial functions, and the dynamics of microbial networks across various samples. These included pure coconut peat (CP1) and pure vermiculite (V1), substrates mixed with organic fertilizer for three days (CP2 and V2), and three combinations cultivated with potatoes for 50 days (CP3, V3, and CV3-a 1:1 mix of coconut peat and vermiculite with organic fertilizer). Vermiculite naturally hosts a more diverse microbial community. After mixing with fertilizer and composting for 3 days, and 50 days of potato cultivation, fungal diversity decreased in both substrates. Coconut peat maintains higher bacterial diversity and richness compared to vermiculite, harboring more beneficial bacteria and fungi, resulting in a more complex microbial network. However, vermiculite shows lower bacterial diversity and richness, with an accumulation of pathogenic microorganisms. Among the 11 environmental factors tested, water-soluble nitrogen (WSN), total nitrogen (TN), available potassium (AK), total organic carbon (TOC) and air-filled porosity (AFP) were significantly associated with microbial succession in the substrate.The nutritional type composition and interaction patterns of indigenous microorganisms differ between vermiculite and coconut peat. Adding abundant nutrients significantly affects the stability and interaction of the entire microbial community, even post-potato cultivation. When using vermiculite for soilless cultivation, precise control and adjustment of nutrient addition quantity and frequency are essential.

Complete chloroplast genome sequences of Phlomis fruticosa and Phlomoides strigosa and comparative analysis of the genus Phlomis sensu lato (Lamiaceae).

The taxonomic terms "Phlomis" and "Phlomoides" had been used to describe two sections within the genus Phlomis belonging to the Lamiaceae family. Recently, phylogenetic analyses using molecular markers showed that Phlomis and Phlomoides formed two monophyletic clades, and thus they are generally accepted as separate genera. In this study, we assembled the complete chloroplast genome of Phlomis fruticosa, which is the first reported chloroplast genome belonging to Phlomis genus, as well as the complete chloroplast genome of Phlomoides strigosa belonging to Phlomoides genus. The results showed that the length of chloroplast genome was 151,639 bp (Phlomis fruticosa) and 152,432 bp (Phlomoides strigosa), with conserved large single copy regions, small single copy regions, and inverted repeat regions. 121 genes in Phlomis fruticosa and 120 genes in Phlomoides strigosa were annotated. The chloroplast genomes of Phlomis fruticosa, Phlomoides strigosa, and three reported Phlomoides species, as well as those of 51 species from the Lamiaceae family, which covered 12 subfamilies, were subjected to phylogenetic analyses. The Phlomis and Phlomoides species were split into two groups, which were well supported by both maximum likelihood and Bayesian inference tree analyses. Our study provided further evidence to recognize Phlomis and Phlomoides as independent genera.

Expression of Potato StDRO1 in Arabidopsis Alters Root Architecture and Drought Tolerance.

Potato (Solanum tuberosum L) is the third important crop for providing calories to a large human population, and is considered sensitive to moderately sensitive to drought stress conditions. The development of drought-tolerant, elite varieties of potato is a challenging task, which can be achieved through molecular breeding. Recently, the DEEPER ROOTING 1 (DRO1) gene has been identified in rice, which influences plant root system and regulates grain yield under drought stress conditions. The potato StDRO1 protein is mainly localized in the plasma membrane of tobacco leaf cells, and overexpression analysis of StDRO1 in Arabidopsis resulted in an increased lateral root number, but decreased lateral root angle, lateral branch angle, and silique angle. Additionally, the drought treatment analysis indicated that StDRO1 regulated drought tolerance and rescued the defective root architecture and drought-tolerant phenotypes of Atdro1, an Arabidopsis AtDRO1 null mutant. Furthermore, StDRO1 expression was significantly higher in the drought-tolerant potato cultivar "Unica" compared to the drought-sensitive cultivar "Atlantic." The transcriptional response of StDRO1 under drought stress occurred significantly earlier in Unica than in Atlantic. Collectively, the outcome of the present investigation elucidated the role of DRO1 function in the alternation of root architecture, which potentially acts as a key gene in the development of a drought stress-tolerant cultivar. Furthermore, these findings will provide the theoretical basis for molecular breeding of drought-tolerant potato cultivars for the farming community.

The Complete Chloroplast Genome Sequence of Eupatorium fortunei: Genome Organization and Comparison with Related Species.

Eupatorium fortunei Turcz, a perennial herb of the Asteraceae family, is one of the horticultural and medicinal plants used for curing various diseases and is widely distributed in China and other Asian countries. It possesses antibacterial, antimetastatic, antiangiogenic, and antioxidant properties along with anticancer potential. However, the intrageneric classification and phylogenetic relationships within Eupatorium have long been controversial due to the lack of high-resolution molecular markers, and the complete chloroplast (cp) genome sequencing has not been reported with new evolutionary insights. In the present study, E. fortunei was used as an experimental material, and its genome was sequenced using high-throughput sequencing technology. We assembled the complete cp genome, and a systematic analysis was conducted for E. fortunei, acquiring the correspondence of its NCBI accession number (OK545755). The results showed that the cp genome of E. fortunei is a typical tetrad structure with a total length of 152,401 bp, and the genome encodes 133 genes. Analysis of the complete cp genomes of 20 Eupatorieae shows that the number of simple sequence repeats (SSRs) ranged from 19 to 36 while the number of long sequence repeats was 50 in all cases. Eleven highly divergent regions were identified and are potentially useful for the DNA barcoding of Eupatorieae. Phylogenetic analysis among 22 species based on protein-coding genes strongly supported that E. fortunei is more closely related to Praxelis clematidea and belongs to the same branch. The genome assembly and analysis of the cp genome of E. fortunei will facilitate the identification, taxonomy, and utilization of E. fortunei as well as provide more accurate evidence for the taxonomic identification and localization of Asteraceae plants.

Exploration of Epigenetics for Improvement of Drought and Other Stress Resistance in Crops: A Review.

Crop plants often have challenges of biotic and abiotic stresses, and they adapt sophisticated ways to acclimate and cope with these through the expression of specific genes. Changes in chromatin, histone, and DNA mostly serve the purpose of combating challenges and ensuring the survival of plants in stressful environments. Epigenetic changes, due to environmental stress, enable plants to remember a past stress event in order to deal with such challenges in the future. This heritable memory, called "plant stress memory", enables plants to respond against stresses in a better and efficient way, not only for the current plant in prevailing situations but also for future generations. Development of stress resistance in plants for increasing the yield potential and stability has always been a traditional objective of breeders for crop improvement through integrated breeding approaches. The application of epigenetics for improvements in complex traits in tetraploid and some other field crops has been unclear. An improved understanding of epigenetics and stress memory applications will contribute to the development of strategies to incorporate them into breeding for complex agronomic traits. The insight in the application of novel plant breeding techniques (NPBTs) has opened a new plethora of options among plant scientists to develop germplasms for stress tolerance. This review summarizes and discusses plant stress memory at the intergenerational and transgenerational levels, mechanisms involved in stress memory, exploitation of induced and natural epigenetic changes, and genome editing technologies with their future possible applications, in the breeding of crops for abiotic stress tolerance to increase the yield for zero hunger goals achievement on a sustainable basis in the changing climatic era.

Reliability and validity of the Chinese version of Rheumatoid Arthritis Self-Efficacy Scale / 中国实用护理杂志

Objective To translate Rheumatoid Arthritis Self-efficacy Scale (RASE) into Chinese and to evaluate its reliability and validity. Methods A total of 188 hospitalized patients with rheumatoid arthritis (RA) were selected as research subjects through convenience sampling method. According to the translation mode of the scale, Chinesization and cultural adjustment were conducted to the English version of RASEto test reliability and validity. Results Item analysis showed that the Chinese version of RASE could discriminate the high-score group from the low-score group (P<0.01). Pearson correlation analysis showed that the correlation coefficient between the score of each item and the total score of the Chinese version of RASE was positively correlated (P<0.01).Exploratory factor analysis extracted a total of 8 common factors, which explained 68.55％of the total variance. The Cronbachαof the Chinese version of RASE was 0.901, and Cronbachαof each dimension ranged from 0.660 to 0.867;the retest reliability was 0.955 after 1 week, and ranged from 0.819 to 0.984 for each dimension;the split-half reliability coefficient was 0.848. Conclusion The Chinese version of RASE has good reliability and validity, which can be applied to the research of self-efficacy of patients with RA in China.

Genetic and epigenetic regulation of PPARγ during adipogenesis.

Peroxisome proliferator-activated receptor gamma (PPARγ) is the master regulator of adipogenesis and adipose tissue development. It also plays crucial roles in many other biological processes, including lipid and glucose metabolism and energy homeostasis. Recently, evidence has been accumulating that the PPARγ gene is not only genetically regulated, but also epigenetically regulated by DNA methylation, histone modification, non-coding RNA and chromosome remodeling. In this review, we summarize the advances in the genetic and epigenetic regulation of the PPARγ gene during adipogenesis, and discuss future research directions and trends for the study of its regulation.

Scanning for New BRI1 Mutations via TILLING Analysis.

The identification and characterization of a mutational spectrum for a specific protein can help to elucidate its detailed cellular functions. BRASSINOSTEROID INSENSITIVE1 (BRI1), a multidomain transmembrane receptor-like kinase, is a major receptor of brassinosteroids in Arabidopsis (Arabidopsis thaliana). Within the last two decades, over 20 different bri1 mutant alleles have been identified, which helped to determine the significance of each domain within BRI1. To further understand the molecular mechanisms of BRI1, we tried to identify additional alleles via targeted induced local lesions in genomes. Here, we report our identification of 83 new point mutations in BRI1, including nine mutations that exhibit an allelic series of typical bri1 phenotypes, from subtle to severe morphological alterations. We carried out biochemical analyses to investigate possible mechanisms of these mutations in affecting brassinosteroid signaling. A number of interesting mutations have been isolated via this study. For example, bri1-702, the only weak allele identified so far with a mutation in the activation loop, showed reduced autophosphorylation activity. bri1-705, a subtle allele with a mutation in the extracellular portion, disrupts the interaction of BRI1 with its ligand brassinolide and coreceptor BRI1-ASSOCIATED RECEPTOR KINASE1. bri1-706, with a mutation in the extracellular portion, is a subtle defective mutant. Surprisingly, root inhibition analysis indicated that it is largely insensitive to exogenous brassinolide treatment. In this study, we found that bri1-301 possesses kinase activity in vivo, clarifying a previous report arguing that kinase activity may not be necessary for the function of BRI1. These data provide additional insights into our understanding of the early events in the brassinosteroid signaling pathway.

Molecular cloning and characterization of an S-adenosylmethionine synthetase gene from Chorispora bungeana.

S-adenosylmethionine synthetase (SAMS) catalyzes the formation of S-adenosylmethionine (SAM) which is a molecule essential for polyamines and ethylene biosynthesis, methylation modifications of protein, DNA and lipids. SAMS also plays an important role in abiotic stress response. Chorispora bungeana (C. bungeana) is an alpine subnival plant species which possesses strong tolerance to cold stress. Here, we cloned and characterized an S-adenosylmethionine synthetase gene, CbSAMS (C. bungeana S-adenosylmethionine synthetase), from C. bungeana, which encodes a protein of 393 amino acids containing a methionine binding motif GHPDK, an ATP binding motif GAGDQG and a phosphate binding motif GGGAFSGDK. Furthermore, an NES (nuclear export signal) peptide was identified through bioinformatics analysis. To explore the CbSAMS gene expression regulation, we isolated the promoter region of CbSAMS gene 1919bp upstream the ATG start codon, CbSAMSp, and analyzed its cis-acting elements by bioinformatics method. It was revealed that a transcription start site located at 320 bp upstream the ATG start codon and cis-acting elements related to light, ABA, auxin, ethylene, MeJA, low temperature and drought had been found in the CbSAMSp sequence. The gene expression pattern of CbSAMS was then analyzed by TR-qPCR and GUS assay method. The result showed that CbSAMS is expressed in all examined tissues including callus, roots, petioles, leaves, and flowers with a significant higher expression level in roots and flowers. Furthermore, the expression level of CbSAMS was induced by low temperature, ethylene and NaCl. Subcellular localization revealed that CbSAMS was located in the cytoplasm and nucleus but has a significant higher level in the nucleus. These results indicated a potential role of CbSAMS in abiotic stresses and plant growth in C. bungeana.

[Responses of Nicotiana tabacum morphology and photosynthetic physiology to reduced ultraviolet-B radiation].

By the method of canopy film-covering to reduce UV-B radiation, this paper studied the responses of the morphology and photosynthetic physiology of Nicotiana tabacum cultivar K326 at its physiological, technical, and physiological-technical transitional maturity stages in high-elevation tobacco-growing area of Yunnan. Three treatments were installed, i.e., reducing 75.74% (T1), 70.08% (T2), and 30.39% (T3) of natural solar UV-B radiation. Reducing UV-B radiation increased the stem height and the internode distance of K326 significantly, with the larger values in T2. Comparing with those under natural UV-B radiation condition, the leaf net photosynthetic rate (Pn), assimilation capacity (AC), water use efficiency (WUE), intrinsic water use efficiency (WUEi), photosynthetic pigments (PP) and flavonoids (FL) contents, and specific leaf mass (SLM) in T1 and T2 all decreased, with larger decrement in T2. The factors affecting the Pn in T, and T2 were stomatal and non-stomatal, and the latter was the main one. The major reason of the lower WUE in T1 and T2 was due to the increase of transpiration rate (Tr) caused by low stomatal regulation capability. In T3, the Pn, AC, WUE, WUEi, and PP increased but the FL and PP decreased to the lowest levels at physiological and transitional maturity stages, and the PP degradation rate was faster at the technical maturity stage.