RESUMEN

With the ongoing intensification of global warming, thermal stress poses significant challenges to tilapia aquaculture. However, the molecular mechanisms underlying the cardiac response of tilapia to high temperatures remain largely unexplored. To address this knowledge gap, we investigated the effects of high-temperature stress on the transcriptomic landscape of the tilapia heart. RNA sequencing was performed on the hearts of Oreochromis aureus (AR), Oreochromis niloticus (NL), and hybrids (O. niloticus ♀ × O. aureus ♂, AN) under treatments of 28 °C, 36 °C, and 39 °C. Using a multi-method approach, including Differentially Expressed Genes analysis, Weighted Gene Co-expression Network Analysis, Fuzzy C-Means, Self-Organizing Map, and Support Vector Machine-Recursive Feature Elimination, we identified six marker genes at 39 °C (AR: ptges3, tuba1a; NL: ran, tcima; AN: slc16a1, fam184b). These genes exhibited strong positive correlations and increased expression under high-temperature conditions. Gene Set Enrichment Analysis and GENIE3 revealed that these marker genes closely regulate three cardiovascular-related pathways: adrenergic signaling in cardiomyocytes, vascular smooth muscle contraction, and cardiac muscle contraction. We hypothesize that the synergistic inhibition of these pathways by marker genes leads to the deterioration of cardiovascular function. In summary, thermal stress activates marker genes, which in turn inhibit cardiovascular pathways, impairing cardiac performance. We propose that these marker genes could serve as dynamic thermal indicators of cardiac performance in tilapia. Additionally, our findings provide theoretical support for improving the management of tilapia farming under high-temperature stress.

RESUMEN

Introduction: Negative oxygen ions are produced by plants through photosynthesis, utilizing "tip discharge" or the photoelectric effect, which has various functions such as sterilization, dust removal, and delaying aging. With global warming, high temperatures may affect the ability of Phalaenopsis aphrodite Rchb. f. to produce negative oxygen ions. P. aphrodite is commonly used in modern landscape planning and forest greening. Methods: In this study, P. aphrodite was selected as the research object. By artificially simulating the climate, the control group (CK) and the high temperature stress group (HS) were set up in the experiment. Results: The study found that compared with the control group, the ability of P. aphrodite to produce negative oxygen ions significantly decreased when exposed to high temperature stress. Meanwhile, under high temperature stress treatment, peroxidase content increased by 102%, and proline content significantly increased by 35%. Discussion: Redundancy analysis results indicated a significant correlation between the root endophytic microbial community of P. aphrodite and negative oxygen ions, as well as physiological indicators. Under high temperature stress, P. aphrodite may affect the regulation of physiological indicators by modifying the composition of root endophytic microbial communities, thereby influencing the ability to release negative oxygen ions.

RESUMEN

BACKGROUND: High temperature stress (HTS) has become a serious threat to rice grain quality and few studies have examined the effects of HTS across multiple stages on rice grain quality. In the present study, we conducted 2 years of HTS treatments under three temperature regimes (32/22 °C, 40/30 °C and 44/34 °C) and HTS durations of 2 days and 4 days at three critical stages: booting, flowering, and a combination of booting and flowering. We employed the heat degree days (HDD) metric, which accounts for both the level and duration of HTS, to quantify the relationships between grain quality traits and HTS. RESULTS: The results revealed the diverse effects of HTS on rice grain quality at different stages, durations and temperature levels. HTS significantly (P < 0.05) reduced grain quality, with the highest sensitivities (reduction per 1 °C day-1 increase in HDD) observed at the flowering stage, followed by the combined and booting stages treatments under mild HTS treatment (40/30 °C). However, under extreme HTS treatments (44/34 °C) for 4 days, rice grains subjected to combined HTS treatment experienced complete mortality. CONCLUSION: Pre-exposed to HTS at the booting stage within a certain intensity can alleviate the adverse effects of post-flowering HTS on grain quality. This provides valuable insights for assessing the potential impact of multiple HTS events on the grain quality under future climate warming. © 2024 Society of Chemical Industry.

RESUMEN

Low temperature is a significant abiotic stress factor that not only impacts plant growth, development, yield, and quality but also constrains the geographical distribution of numerous wild plants. Kohlrabi (Brassica oleracea L. var. caulorapa L.) belongs to the Brassicaceae family and has a short growing period. In this study, a total of 196,642 unigenes were obtained from kohlrabi seedlings at low temperatures; of these, 52,836 unigenes were identified as differentially expressed genes. Transcription factor family members ARR-B, C3H, B3-ARF, etc. that had a high correlation with biochemical indicators related to low temperature were identified. A total of nineteen BocARR-B genes (named BocARR-B1-BocARR-B19) were obtained, and these genes were distributed unevenly across seven chromosomes. Nineteen BocARR-B genes searched four conserved motifs and were divided into three groups. The relative expression level analysis of 19 BocARR-B genes of kohlrabi showed obvious specificity in different tissues. This study lays a foundation and provides new insight to explain the low-temperature resistance mechanism and response pathways of kohlrabi. It also provides a theoretical basis for the functional analysis of 19 BocARR-B transcription factor gene family members.

Asunto(s)

RESUMEN

Low-temperature (LT) is one of the major abiotic stresses that restrict the growth and development of maize seedlings. Brassinolides (BRs) have been shown to enhance LT tolerance in several plant species; the physiological and molecular mechanisms by which BRs enhance maize tolerance are still unclear. Here, we characterized changes in the physiology and transcriptome of N192 and Ji853 seedlings at the three-leaf stage with or without 2 µM 2,4-epibrassinolide (EBR) application at 25 and 15 °C environments via high-performance liquid chromatography and RNA-Sequencing. Physiological analyses revealed that EBR increased the antioxidant enzyme activities, enhanced the cell membrane stability, decreased the malondialdehyde formation, and inhibited the reactive oxygen species (ROS) accumulation in maize seedlings under 15 °C stress; meanwhile, EBR also maintained hormone balance by increasing indole-3-acetic acid and gibberellin 3 contents and decreasing the abscisic acid level under stress. Transcriptome analysis revealed 332 differentially expressed genes (DEGs) enriched in ROS homeostasis, plant hormone signal transduction, and the mitogen-activated protein kinase (MAPK) cascade. These DEGs exhibited synergistic and antagonistic interactions, forming a complex LT tolerance network in maize. Additionally, weighted gene co-expression network analysis (WGCNA) revealed that 109 hub genes involved in LT stress regulation pathways were discovered from the four modules with the highest correlation with target traits. In conclusion, our findings provide new insights into the molecular mechanisms of exogenous BRs in enhancing LT tolerance of maize at the seedling stage, thus opening up possibilities for a breeding program of maize tolerance to LT stress.

Asunto(s)

RESUMEN

Global warming is a leading environmental stress that reduces plant productivity worldwide. Several beneficial microorganisms reduce stress; however, the mechanism by which plant-microbe interactions occur and reduce stress remains to be fully elucidated. The aim of the present study was to elucidate the mutualistic interaction between the plant growth-promoting rhizobacterial strain SH-19 and soybeans of the Pungsannamul variety. The results showed that SH-19 possessed several plant growth-promoting traits, such as the production of indole-3-acetic acid, siderophore, and exopolysaccharide, and had the capacity for phosphate solubilisation. The heat tolerance assay showed that SH-19 could withstand temperatures up to 45 °C. The strain SH-19 was identified as P. megaterium using the 16S ribosomal DNA gene sequence technique. Inoculation of soybeans with SH-19 improved seedling characteristics under high-temperature stress. This may be due to an increase in the endogenous salicylic acid level and a decrease in the abscisic acid level compared with the negative control group. The strain of SH-19 increased the activity of the endogenous antioxidant defense system, resulting in the upregulation of GSH (44.8%), SOD (23.1%), APX (11%), and CAT (52.6%). Furthermore, this study involved the transcription factors GmHSP, GmbZIP1, and GmNCED3. The findings showed upregulation of the two transcription factors GmbZIP1 (17%), GmNCED3 (15%) involved in ABA biosynthesis and induced stomatal regulation, similarly, a downregulation of the expression pattern of GmHSP by 25% was observed. Overall, the results of this study indicate that the strain SH-19 promotes plant growth, reduces high-temperature stress, and improves physiological parameters by regulating endogenous phytohormones, the antioxidant defense system, and genetic expression. The isolated strain (SH-19) could be commercialized as a biofertilizer.

Asunto(s)

RESUMEN

Rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) is an important economic cold-water fish that is susceptible to heat stress. To date, the heat stress response in rainbow trout is more widely understood at the transcriptional level, while little research has been conducted at the translational level. To reveal the translational regulation of heat stress in rainbow trout, in this study, we performed a ribosome profiling assay of rainbow trout liver under normal and heat stress conditions. Comparative analysis of the RNA-seq data with the ribosome profiling data showed that the folding changes in gene expression at the transcriptional level are moderately correlated with those at the translational level. In total, 1213 genes were significantly altered at the translational level. However, only 32.8% of the genes were common between both levels, demonstrating that heat stress is coordinated across both transcriptional and translational levels. Moreover, 809 genes exhibited significant differences in translational efficiency (TE), with the TE of these genes being considerably affected by factors such as the GC content, coding sequence length, and upstream open reading frame (uORF) presence. In addition, 3468 potential uORFs in 2676 genes were identified, which can potentially affect the TE of the main open reading frames. In this study, Ribo-seq and RNA-seq were used for the first time to elucidate the coordinated regulation of transcription and translation in rainbow trout under heat stress. These findings are expected to contribute novel data and theoretical insights to the international literature on the thermal stress response in fish.

Asunto(s)

RESUMEN

BACKGROUND: Dermatophagoides farinae proteins (DFPs) are abundantly expressed in D. farinae; however, their functions remain unknown. Our previous transcriptome sequencing analyses revealed that the basal expression of DFP1 and DFP2 in D. farinae was high and, more importantly, upregulated under temperature stress. Therefore, DFPs were speculated to exert a temperature stress response function. RESULTS: Real-time quantitative polymerase chain reaction detection revealed that both DFP1 and DFP2 were significantly upregulated under temperature stress. Particularly, DFP1 was upregulated under cold stress. Electrophoresis of D. farinae total proteins revealed an increased abundance of DFP1 and DFP2 (40-55 kDa bands) under temperature stress, which was corroborated by the mass spectrometry results. After silencing DFP1 and DFP2 further, temperature stress led to decreases in gene expression and survival rates. Moreover, DFP1 was identified as the upstream regulator of DFP2. CONCLUSION: This study highlights the temperature stress response functions of DFP1 and DFP2 at the mRNA and protein levels. These results provide important insights for applying DFP1 and DFP2 as potential target genes for the molecular prevention and control of D. farinae to prevent allergic diseases. The newly established methods provide methodological guidance for the study of genes with unknown functions in mites.

Asunto(s)

RESUMEN

Catalpa bungei, a tree indigenous to China, is renowned for its superior timber quality and as an ornamental in horticulture. To promote the cultivation of C. bungei in cold regions and expand its distribution, enhancing its cold tolerance is essential. The CCCH gene family is widely involved in plant growth, development, and expression under stress conditions, including low-temperature stress. However, a comprehensive identification and analysis of these genes have not yet been conducted. This study aims to identify key cold-tolerance-related genes within the CCCH gene family of C. bungei, providing the necessary theoretical support for its expansion in cold regions. In this study, 61 CCCH genes within C. bungei were identified and characterized. Phylogenetic assessment divided these genes into 9 subfamilies, with 55 members mapped across 16 chromosomes. The analysis of gene structures and protein motifs indicated that members within the same subfamily shared similar exon/intron distribution and motif patterns, supporting the phylogenetic classification. Collinearity analysis suggested that segmental duplications have played a significant role in the expansion of the C. bungei CCCH gene family. Notably, RNA sequencing analysis under 4 °C cold stress conditions identified CbuC3H24 and CbuC3H58 as exhibiting the most significant responses, highlighting their importance within the CCCH zinc finger family in response to cold stress. The findings of this study lay a theoretical foundation for further exploring the mechanisms of cold tolerance in C. bungei, providing crucial insights for its cultivation in cold regions.

Asunto(s)

RESUMEN

High temperature stress has long-term negative effects on the growth and development of silkworm (Bombyx mori). Different silkworm varieties show the different tolerance to high temperature. The induction of autophagy is linked to increased thermotolerance in diverse ectothermic organisms. However, the function of autophagy in the thermotolerant and thermosensitive silkworm strains under high-temperature conditions remains unclear. The thermotolerant Liangguang NO.2 and thermosensitive Jingsong × Haoyue strains were used to explore the role of autophagy in thermotolerance. Here, we first found that the larval body weight gain was increased in the thermosensitive Jingsong × Haoyue strain, but there was no difference in the thermotolerant Liangguang NO.2 strain under high temperature conditions. High temperature stress had a negative influence on the cocoon performance in both the Liangguang NO.2 and Jingsong × Haoyue strains. Additionally, the autophagy-related gene Atg5 mRNA expression in the Liangguang NO.2 strain was upregulated by high temperature, while the expression of Atg12 mRNA was reduced in the Jingsong × Haoyue strain. Titers of 20-Hydroxyecdysone and the ultraspiracle 1 mRNA expression in the Liangguang NO.2 strain were upregulated by high temperature, which might be associated with the induction of autophagy. These results demonstrate the potentially regulatory mechanism of autophagy in silkworms' tolerance to high temperature, providing a theoretical basis for exploring the physiological mechanism of thermotolerance in insects.

Asunto(s)

RESUMEN

High temperature stress is one of the most severe forms of abiotic stress in alfalfa. With the intensification of climate change, the frequency of high temperature stress will further increase in the future, which will bring challenges to the growth and development of alfalfa. Therefore, untargeted metabolomic and RNA-Seq profiling were implemented to unravel the possible alteration in alfalfa seedlings subjected to different temperature stress (25 ℃, 30 ℃, 35 ℃, 40 ℃) in this study. Results revealed that High temperature stress significantly altered some pivotal transcripts and metabolites. The number of differentially expressed genes (DEGs) markedly up and down-regulated was 1876 and 1524 in T30_vs_CK, 2, 815 and 2667 in T35_vs_CK, and 2115 and 2, 226 in T40_vs_CK, respectively. The number for significantly up-regulated and down-regulated differential metabolites was 173 and 73 in T30_vs_CK, 188 and 57 in T35_vs_CK, and 220 and 66 in T40_vs_CK, respectively. It is worth noting that metabolomics and transcriptomics co-analysis characterized enriched in plant hormone signal transduction (ko04705), glyoxylate and dicarboxylate metabolism (ko00630), from which some differentially expressed genes and differential metabolites participated. In particular, the content of hormone changed significantly under T40 stress, suggesting that maintaining normal hormone synthesis and metabolism may be an important way to improve the HTS tolerance of alfalfa. The qRT-PCR further showed that the expression pattern was similar to the expression abundance in the transcriptome. This study provides a practical and in-depth perspective from transcriptomics and metabolomics in investigating the effects conferred by temperature on plant growth and development, which provided the theoretical basis for breeding heat-resistant alfalfa.

Asunto(s)

RESUMEN

Antibiotic resistance has become one of the most critical issues in the field of public health in recent years. Exposure to food environment stresses may result in the development of antibiotic resistance in Salmonella. The present study aimed to investigate the simultaneous effects of food-related stresses (osmotic pressure, acid, heat, cold, and freezing stresses) on the antibiotic resistance changes in Salmonella Enteritidis and Salmonella Typhimurium. A factorial design with five factors at two levels was used to evaluate the main and interactive effects of stress factors on the antibiotic resistance of Salmonella serotypes. The changes in the antibiotic resistance of Salmonella serotypes were evaluated using the disc diffusion assay. The results showed that the different stresses had different effects on the antibiotic resistance of Salmonella serotypes. The freezing time and osmotic stresses had the most significant effects on the antibiotic resistance (P < 0.05). S. Enteritidis showed the slightest changes after exposure to stresses. The results also showed that a low level (24 h) of freezing time decreased the antibiotic resistance, but at a high level (96 h) increased it. The results emphasized that food processing and storage conditions should be considered as crucial factors in developing antibiotic resistance in Salmonella.

RESUMEN

Pinus massoniana L. is one of the most important conifer species in southern China and is the mainstay of the forest ecosystem and timber production, yet low temperatures limit its growth and geographical distribution. This study used 30-day-old seedlings from families of varying cold-tolerance to examine the morphological traits of needles and stems, chlorophyll fluorescence characteristics, protective enzymes, and changes in starch and lignin under different low-temperature stresses in an artificial climate chamber. The results showed that the seedlings of Pinus massoniana exhibited changes in phenotypic morphology and tissue structure under low-temperature stress. Physiological and biochemical indexes such as protective enzymes, osmoregulatory substances, starch, and lignin responded to low-temperature stress. The cold-tolerant family increased soluble sugars, starch grain, and lignin content as well as peroxidase activity, and decreased malondialdehyde content by increasing the levels of actual photochemical efficiency (ΦPSII), electron transport rate (ETR), and photochemical quenching (qP) to improve the cold tolerance ability. This study provides a reference for the selection and breeding of cold-tolerant genetic resources of Pinus massoniana and the mechanism of cold-tolerance, as well as the analysis of the mechanism of adaptation of Pinus massoniana in different climatic regions of China.

RESUMEN

The commercialization of 2,4-D (2,4-dichlorophenoxyacetic acid) latifolicide in 1945 marked the beginning of the selective herbicide market, with this active ingredient playing a pivotal role among commercial herbicides due to the natural tolerance of monocots compared with dicots. Due to its intricate mode of action, involving interactions within endogenous auxin signaling networks, 2,4-D was initially considered a low-risk herbicide to evolve weed resistance. However, the intensification of 2,4-D use has contributed to the emergence of 2,4-D-resistant broadleaf weeds, challenging earlier beliefs. This review explores 2,4-D tolerance in crops and evolved resistance in weeds, emphasizing an in-depth understanding of 2,4-D metabolic detoxification. Nine confirmed 2,4-D-resistant weed species, driven by rapid metabolism, highlight cytochrome P450 monooxygenases in Phase I and glycosyltransferases in Phase II as key enzymes. Resistance to 2,4-D may also involve impaired translocation associated with mutations in auxin/indole-3-acetic acid (Aux/IAA) co-receptor genes. Moreover, temperature variations affect 2,4-D efficacy, with high temperatures increasing herbicide metabolism rates and reducing weed control, while drought stress did not affect 2,4-D efficacy. Research on 2,4-D resistance has primarily focused on non-target-site resistance (NTSR) mechanisms, including 2,4-D metabolic detoxification, with limited exploration of the inheritance and genetic basis underlying these traits. Resistance to 2,4-D in weeds is typically governed by a single gene, either dominant or incompletely dominant, raising questions about gain-of-function or loss-of-function mutations that confer resistance. Future research should unravel the physiological and molecular-genetic basis of 2,4-D NTSR, exploring potential cross-resistance patterns and assessing fitness costs that may affect future evolution of auxin-resistant weeds. © 2024 Society of Chemical Industry.

RESUMEN

This experiment was conducted to explore the effects of dietary vitamin C supplementation on non-specific immune defense, antioxidant capacity and resistance to low-temperature stress of juvenile mud crab (Scylla paramamosain). Mud crabs with an initial weight of 14.67 ± 0.13 g were randomly divided into 6 treatments and fed diets with 0.86 (control), 44.79, 98.45, 133.94, 186.36 and 364.28 mg/kg vitamin C, respectively. The experiment consisted of 6 treatments, each treatment was designed with 4 replicates and each replicate was stocked with 8 crabs. After 42 days of feeding experiment, 2 crabs were randomly selected from each replicate, and a total of 8 crabs in each treatment were carried out 72 h low-temperature challenge experiment. The results showed that crabs fed diets with 186.36 and 364.28 mg/kg vitamin C significantly improved the activities of alkaline phosphatase (AKP) and acid phosphatase (ACP) in hemolymph and hepatopancreas (P < 0.05). Crabs fed diet with 133.94 mg/kg vitamin C significantly decreased the concentration of nitric oxide (NO) and the activity of nitric oxide synthase (NOS) in hemolymph (P < 0.05). Diet with 133.94 mg/kg vitamin C was improved the activity of polyphenol oxidase (PPO) and the concentration of albumin (ALB) in hemolymph. Crabs fed diet with 133.94 mg/kg vitamin C showed lower concentration of malondialdehyde (MDA) in hemolymph and hepatopancreas than those fed the other diets. Meanwhile, crabs fed diet with 98.45 mg/kg vitamin C showed higher activity of total superoxide dismutase (T-SOD) in hemolymph, and crabs fed diet with 133.94 mg/kg vitamin C showed higher activity of T-SOD in hepatopancreas. Crabs fed diet with 186.36 mg/kg vitamin C significantly decreased the concentration of reduced glutathione (GSH) and the activity of glutathione peroxidase (GSH-PX) in hepatopancreas (P < 0.05). In normal temperature, crabs fed diets with 133.94 mg/kg vitamin C significantly up-regulated the expression levels of gpx (glutathione peroxidase) and trx (thioredoxin) in hepatopancreas compared with the control treatment (P < 0.05). The highest expression levels of relish, il16 (interleukin 16), caspase 2 (caspase 2), p38 mapk (p38 mitogen-activated protein kinases) and bax (bcl-2 associated x protein) in hepatopancreas were found at crabs fed control diet (P < 0.05). Moreover, crabs fed diet with 133.94 mg/kg vitamin C showed higher expression levels of alf-3 (anti-lipopolysaccharide factor 3) and bcl-2 (B-cell lymphoma 2) in hepatopancreas than those fed the other diets (P < 0.05). Under low-temperature stress, crabs fed diet with 133.94 mg/kg vitamin C significantly improved the expression levels of hsp90 (heat shock protein 90), cat (catalase), gpx, prx (thioredoxin peroxidase) and trx in hepatopancreas (P < 0.05). In addition, dietary with 133.94 vitamin C significantly up-regulated the expression levels of alf-3 and bcl-2 (P < 0.05). Based on two slope broken-line regression analysis of activity of PPO against the dietary vitamin C level, the optimal dietary vitamin C requirement was estimated to be 144.81 mg/kg for juvenile mud crab. In conclusion, dietary 133.94-144.81 mg/kg vitamin C significantly improved the non-specific immune defense, antioxidant capacity and resistance to low-temperature stress of juvenile mud crab.

Asunto(s)

RESUMEN

Low temperature (LT) is an important environmental factor affecting the growth and yield of plants. Melatonin (MT) can effectively enhance the LT tolerance of cucumber. This study found that LT stress induced the expression of Comt1 (caffeic acid O-methyltransferase 1), with the highest expression being about 2-times that of the control. Meanwhile, the content of MT was found to be roughly 63.16% of that in the control samples. Compared with LT treatment alone, exogenous MT pretreatment upregulated the expression levels of TOR (Target of rapamycin), PIN1 (Pin-formed 1), and YUC4 (YUCCA 4), with maximum upregulations reaching approximately 66.67%, 79.32%, and 42.86%, respectively. These results suggest that MT may modulate the tolerance of cucumber seedlings to LT stress by regulating the expression of TOR, PIN1, and YUC4. In addition, co-treatment with AZD-8055 (a TOR inhibitor) or NPA (N-1-naphthylphthalamic acid, an auxin polar transport inhibitor) and MT attenuated MT-induced resistance to LT stress, leading to higher levels of reactive oxygen species (ROS), reduced antioxidant defense capacity, and increased damage to the membrane system in cucumber seedlings. Concurrently, the content of osmoregulatory substances and the photosynthesis decreased. These results demonstrate that both TOR and auxin were required for MT to alleviate LT-induced damage in cucumber. In summary, the present study demonstrates that TOR and auxin signaling synergistically contribute to alleviating LT damage in cucumber seedlings by exogenous MT. These findings help us understand the function of MT and provide insights into the regulatory network of MT that regulates the LT tolerance of plants.

Asunto(s)

RESUMEN

Global wheat production amounted to >780 MMT during 2022-2023 whose market size are valued at >$128 billion. Wheat is highly susceptible to high-temperature stress (HTS) throughout the life cycle and its yield declines 5-7% with the rise in each degree of temperature. Previously, we reported an array of HTS-response markers from a resilient wheat cv. Unnat Halna and described their putative role in heat acclimation. To complement our previous results and identify the key determinants of thermotolerance, here we examined the cytoplasmic proteome of a sensitive cv. PBW343. The HTS-triggered metabolite reprograming highlighted how proteostasis defects influence the formation of an integrated stress-adaptive response. The proteomic analysis identified several promising HTS-responsive proteins, including a NACα18 protein, designated TaNACα18, whose role in thermotolerance remains unknown. Dual localization of TaNACα18 suggests its crucial functions in the cytoplasm and nucleus. The homodimerization of TaNACα18 anticipated its function as a transcriptional coactivator. The complementation of TaNACα18 in yeast and overexpression in wheat demonstrated its role in thermotolerance across the kingdom. Altogether, our results suggest that TaNACα18 imparts tolerance through tight regulation of gene expression, cell wall remodeling and activation of cell defense responses.

Asunto(s)

RESUMEN

Apple is an important horticultural crop, but various adverse environmental factors can threaten the quality and yield of its fruits. The ability of apples to resist stress mainly depends on the rootstock. Malus baccata (L.) Borkh. is a commonly used rootstock in Northeast China. In this study, it was used as the experimental material, and the target gene MbWRKY53 was screened through transcriptome analysis and Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction (RT-qPCR) after cold and drought treatment. Bioinformatics analysis revealed that this transcription factor (TF) belonged to the WRKY TF family, and its encoded protein was localized in the nucleus. RT-qPCR showed that the gene was more easily expressed in roots and young leaves and is more responsive to cold and drought stimuli. Functional validation in Arabidopsis thaliana confirmed that MbWRKY53 can enhance plant tolerance to cold and drought stress. Furthermore, by analyzing the expression levels of genes related to cold and drought stress in transgenic Arabidopsis lines, it was inferred that this gene can regulate the expression of stress-related genes through multiple pathways such as the CBF pathway, SOS pathway, Pro synthesis pathway, and ABA-dependent pathways, enhancing the adaptability of transgenic Arabidopsis to cold and drought environments.

Asunto(s)

RESUMEN

Sodium nitroprusside (SNP) is a potent nitric oxide (NO) donor that enhances plant tolerance to various abiotic stresses. This research aims to assess the effect of SNP application on rice seedlings subjected to individual and combined exposure to two abiotic stresses viz., low-temperature (LT) and chromium (Cr). Exposure to LT, Cr, and LT+Cr caused severe oxidative damage by stimulating greater production and accumulation of reactive oxygen species (ROS) leading to lipid peroxidation and cell membrane instability. The combined LT+CR stress more intensly increased the cellular oxidative stress and excessive Cr uptake that in turn deteriorated the chlorophyll pigments and photosynthesis, as well as effected the level of tetrapyrrole biosynthesis in rice plants. The reduction in rice seedling growth was more obvious under LT+Cr treatment than their individual effects. The exogenous application of SNP diminished the toxic impact of LT and Cr stress. This was attributed to the positive role of SNP in regulating the endogenous NO levels, free amino acids (FAAs) contents, tetrapyrrole biosynthesis and antioxidants. Consequently, SNP-induced NO decreased photorespiration, ROS generation, lipid peroxidation, and electrolyte leakage. Moreover, exogenous SNP diminished the Cr uptake and accumulation by modulating the ionic homeostasis and strengthening the heavy metals detoxification mechanism, thus improving plant height, biomass and photosynthetic indexes. Essentially, SNP boosts plant tolerance to LT and Cr stress by regulating antioxidants, detoxification mechanism, and the plant's physio-biochemical. Hence, applying SNP is an effective method for boosting rice plant resilience and productivity in the face of escalating environmental stresses and pollutants.

Asunto(s)

RESUMEN

Melatonin (Mel) is recognized as a prominent plant growth regulator. This study investigated the alleviating effect of Mel pretreatment on growth inhibition caused by low-temperature (LT) stress (10 °C/6 °C) in cucumber seedlings and explored the role of the Ca2+/Calcium-dependent protein kinases (CPKs) signaling pathway in Mel-regulated LT tolerance. The main results are as follows: compared to LT treatment alone, 100 µM Mel increased both the content of Ca2+ (highest about 42.01%) and the expression levels of Ca2+ transporter and cyclic nucleotide-gated channel (CNGC) genes under LT. Similarly, Mel enhanced the content of CPKs (highest about 27.49%) and the expression levels of CPKs family genes in cucumber leaves under LT. Additionally, pretreatment with 100 µM Mel for three days strengthened the antioxidant defense and photosynthesis of seedlings under LT. Genes in the ICE-CBF-COR pathway and the MAPK cascade were upregulated by Mel, with maximum upregulations reaching approximately 2.5-fold and 1.9-fold, respectively, thus conferring LT tolerance to cucumber seedlings. However, the above beneficial effects of Mel were weakened by co-treatment with calcium signaling blockers (LaCl3 or EGTA) or CPKs inhibitors (TFP or W-7), suggesting that the Ca2+/CPKs pathway is involved in the Mel-mediated regulation of LT tolerance. In conclusion, this study revealed that Mel can alleviate growth inhibition in cucumber seedlings under LT stress and demonstrated that the Ca2+/CPKs signaling pathway is crucial for the Mel-mediated enhancement of LT tolerance. The findings hold promise for providing theoretical insights into the application of Mel in agricultural production and for investigating its underlying mechanisms of action.

Asunto(s)