Groundwater nitrate contamination in intensive croplands often persists despite strong short-term weather variability, suggesting that near-surface signals may not translate directly to aquifers. We tested this across a four-site south-to-north transect in Henan Province, China, under a wheat-maize rotation. For each sampling event, we quantified antecedent hydroclimatic windows from daily meteorological data, and measured depth-integrated (0-50 cm) soil inorganic N stocks, soil N-cycling enzyme activities, groundwater NO3--N, and nitrate isotopes (δ15N-NO3- and δ18O-NO3-). Principal component analysis summarized hydroclimatic variability into two dominant gradients: a dry-frequency axis (PC1) and an evaporative-demand axis (PC2). Drier antecedent conditions (higher dry-frequency scores) were consistently associated with greater 0-50 cm soil NO3- storage and coordinated changes in enzyme indices related to N turnover; the dry-frequency gradient accounted for 41% of the variance in soil NO3--N stocks. In contrast, groundwater nitrate showed weak short-term coupling across all window lengths, with only 19% of NO3- variability explained and no significant contemporaneous associations with short-term soil indicators or hydroclimate axes. Isotope patterns showed strong site- and stage-dependent scatter: groundwater δ15N-NO3- varied widely (3.5-17.5‰) while δ18O-NO3- remained narrow (7.0-8.9‰), consistent with mixing among multiple nitrate sources and transport lags that buffer legacy signals in the aquifer. These results help explain why groundwater nitrate remains poorly predictable from short-term surface indicators, and they support management strategies that prioritize sustained reductions in long-term N surplus and monitoring designs that account for subsurface storage and time lags.

Background Global climate change is rapidly impacting biodiversity and threatening the sustainable use of medicinal plant species by reducing their availability and increasing harvest uncertainty. Understanding the adaptive genetic variation and genetic vulnerability of medicinal plants under climate change is crucial for effective germplasm management, cultivation, and breeding efforts. In this study, we assessed the genetic differentiation, local adaptation, and genomic vulnerability of the medicinal plant Isodon rubescens (Hemsl.) H. Hara, with the goals of elucidating the impacts of geographic and environmental factors on its genetic structure and identifying at-risk populations for informed conservation and breeding under climate change. Results We applied restriction site-associated DNA sequencing (RAD-seq) to 17 populations of I. rubescens spanning its central and peripheral ranges, including the Taihang and Qinling-Funiu Mountains. The analysis revealed two distinct genetic groups: one in the Taihang Mountains and the other in the Qinling-Funiu Mountains. Significant patterns of isolation by distance (IBD), environment (IBE), and resistance (IBR) were detected, alongside high niche differentiation. We identified 456 candidate adaptive SNPs, some linked to genes involved in stress responses and biosynthesis. Precipitation was a key environmental driver of local adaptation. Populations in the northern Taihang Mountains and southern Funiu Mountains showed higher genomic vulnerability, indicating a greater risk of maladaptation. Conclusion Our findings demonstrate that geographic isolation and environmental factors, particularly precipitation, are key drivers of genetic differentiation and local adaptation in I. rubescens . The identified genomic vulnerability pinpoints specific populations at high risk under climate change. These insights provide a crucial genetic basis for formulating targeted conservation strategies and developing climate-resilient breeding programs for this medicinal species.

The forest ecosystem is a significant pool for capturing atmospheric mercury (Hg) deposition, with most Hg accumulating in forest soils. As secondary forests now dominate global forest cover, they are particularly sensitive to changes in ambient temperature. However, the impact of these changes on Hg dynamics in secondary forests remains poorly understood. Here, we quantified Hg inputs, outputs, and mass balances in two secondary forests in China, each with different ambient temperatures. We found that elevated ambient temperature (similar to 1.0 degrees C) advanced the germination of leaves by 2-3 days and extended the growing season by approximately one week, resulting in increased litterfall biomass by 1.18 Mg hm(-2) yr(-1) and a thicker litterfall layer by 0.22 cm over 34 years. This temperature rise also facilitated Hg methylation within forest and enhanced methylmercury (MeHg) export, heightening the potential risk of MeHg exposure to surrounding ecosystems. Additionally, higher ambient temperature not only increased soil Hg emissions (2.75 mu g m(-2) yr(-1)) but also led to significant Hg deposition via litterfall (9.26 mu g m(-2) yr(-1)), resulting in a net annual Hg deposition of 6.88 mu g m(-2) yr(-1). This net Hg deposition accumulated in the topsoil, increasing the Hg pool by 0.51 mg m(-2) in organic and 0-10 cm mineral soil horizons. Our findings suggest that even a similar to 1.0 degrees C temperature rise could enhance the role of secondary forests as atmospheric Hg sink by 45.10 %. Therefore, the impact of ongoing climate warming on Hg cycling and pools in forests should receive increased attention and warrants further research.

BACKGROUND:Rhizosphere microorganisms and their interactions play a critical role in enhancing plant disease resistance. Here, we found that the disease severity of the resistant variety LW025 showed a decreasing trend with the increase in continuous cropping cycles. However, the mechanisms underlying the reduction in disease severity during the continuous cropping of the resistant watermelon variety LW025, particularly its relationship with the rhizosphere microbiome, remain unclear. RESULTS:In this study, the transcriptome of different watermelon varieties after continuous planting in pathogen-containing and pathogen-free soils was analyzed. The results showed that only two genes expression showed significant differences in disease-resistant variety between healthy and diseased soils. Subsequently, we analyzed the differences of rhizosphere soil microbial communities after planting different watermelon varieties for three consecutive seasons, as well as the relationship between differential microorganisms and soil physiochemical properties and soil enzyme activity. The results demonstrated continuous cropping of the disease-resistant variety LW025 formed a rhizosphere microbiome different from the initial soil and susceptible variety. Specifically, fungal changes were primarily observed in Ascomycota and Chytridiomycota, while bacterial changes were mainly observed in Cyanobacteria and Gemmatimonadetes. The bacterial functions enriched in the rhizosphere of the resistant variety LW025 after continuous cropping were primarily associated with soil nitrogen cycling. Furthermore, the plant disease index showed a significant positive correlation with the available phosphorus and potassium content in the soil, while exhibiting a significant negative correlation with soil pH and catalase activity. CONCLUSIONS:Overall, the reduction in disease severity associated with continuous cropping of the disease-resistant variety LW025 was more closely related to changes in the rhizosphere microecological environment. This study explained the mechanism of the resistant variety LW025 against Fusarium infection, and provided new prospects for the development of technologies based on rhizosphere microecological environment modification to improve the resistance of watermelon to Fusarium wilt.

Rapid climate change is affecting biodiversity and threatening locally adapted species. Relict species are often confined to relatively narrow, discontinuous geographic ranges and provide excellent opportunities to study local adaptation and extinction. Understanding the adaptive genetic variation and genetic vulnerability of relict species under climate change is essential for their conservation and management efforts. Here, we applied a landscape genomics approach to investigate the population genetic structure and predict adaptive capacity to climatic change for Taiwania cryptomerioides Hayata, a vulnerable Tertiary relict tree species in China. We used restriction site-associated DNA sequencing on 122 individuals across 10 sampling sites. We found three genetic groups across the Chinese range of T. cryptomerioides: the southwest, central-eastern, and Taiwanese groups. We detected significant signals of isolation by environment and isolation by distance, with environment playing a more important role than geography in shaping spatial genetic variation in T. cryptomerioides. Moreover, some outliers were related to defense and stress responses, which could reflect the genomic basis of adaptation. Gradient forest (GF) analysis revealed that precipitation-related variables were important in driving adaptive variation in T. cryptomerioides. Ecological niche modeling and GF analysis revealed that the central-eastern populations were more vulnerable to future climate change than other populations, with range contractions and high genetic offsets, suggesting these populations may be at higher risk of decline or local extinction. These findings deepen our understanding of local adaptation and vulnerability to climate change in relict tree species and will guide conservation and restoration programs for T. cryptomerioides in the future.

Rapeseed (Brassica napus L.) is susceptible to nutrient stresses during growth and development; however, the CPA (cation proton antiporter) family genes have not been identified in B. napus and their biological functions remain unclear. This study was aimed to identify the molecular characteristics of rapeseed CPAs and their transcriptional responses to multiple nutrient stresses. Through bioinformatics analysis, 117 BnaCPAs, consisting of three subfamilies: Na+/H+ antiporter (NHX), K+ efflux antiporter (KEA), and cation/H+ antiporter (CHX), were identified in the rapeseed genome. Transcriptomic profiling showed that BnaCPAs, particularly BnaNHXs, were transcriptionally responsive to diverse nutrient stresses, including Cd toxicity, K starvation, salt stress, NH4+ toxicity, and low Pi. We found that the salt tolerance of the transgenic rapeseed lines overexpressing BnaA05.NHX2 was significantly higher than that of wild type. Subcellular localization showed that BnaA05.NHX2 was localized on the tonoplast, and TEM combined with X-ray energy spectrum analysis revealed that the vacuolar Na+ concentrations of the BnaA05.NHX2-overexpressing rapeseed plants were significantly higher than those of wild type. The findings of this study will provide insights into the complexity of the BnaCPA family and a valuable resource to explore the in-depth functions of CPAs in B. napus.

Variations in the resistance to potassium (K) deficiency among rapeseed genotypes emphasize complicated regulatory mechanisms. In this study, a low-K-sensitivity accession (L49) responded to K deficiency with smaller biomasses, severe leaf chlorosis, weaker photosynthesis ability, and deformed stomata morphology compared to a low-K resistant accession (H280). H280 accumulated more K+ than L49 under low K. Whole-genome resequencing (WGS) revealed a total of 5,538,622 single nucleotide polymorphisms (SNPs) and 859,184 insertions/deletions (InDels) between H280 and L49. RNA-seq identified more differentially expressed K+ transporter genes with higher expression in H280 than in L49 under K deficiency. Based on the K+ profiles, differential expression profiling, weighted gene coexpression network analysis, and WGS data between H280 and L49, BnaC4.AKT1 was proposed to be mainly responsible for root K absorption-mediated low K resistance. BnaC4.AKT1 was expressed preferentially in the roots and localized on the plasma membrane. An SNP and an InDel found in the promoter region of BnaC4.AKT1 were proposed to be responsible for its differential expression between rapeseed genotypes. This study identified a gene resource for improving low-K resistance. It also facilitates an integrated knowledge of the differential physiological and transcriptional responses to K deficiency in rapeseed genotypes.

Cytochrome P450 (CYP450) proteins are a large group of monooxygenase that play important roles in the biosynthesis of secondary metabolites and degradation of xenobiotics. However, the responses of CYP450 family to abiotic stresses have not been characterized in Brassica napus (B. napus). In this study, we identified a total of 384 CYP450 genes in Darmor-bzh, the rapeseed culture whose genome was wildly used as a reference for gene clone. The structure and localization analyses showed that BnaCYP450 genes have integrated heme-binding motif, contain 1–10 exons, unevenly distributed across all the 19 chromosomes, and mainly localized on chloroplast. Cis-regulation element analysis suggested that BnaCYP450 genes were transcriptionally regulated by hormone and multiple stress response signals. Transcript expression analyses identified 108, 85, 96, and 86 BnaCYP450s differentially expressed genes (DEGs) in response to salt stress, potassium deficiency, nitrogen stress, and cadmium toxicity, respectively. Gene ontology (GO) enrichment analysis indicated that these BnaCYP450 DEGs mainly enriched in molecular function of ion binding and oxidoreductase activity and the biological process of secondary product metabolism. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that they mainly involved in the pathway of isoflavonoid biosynthesis. Differential expression of BnaCYP450s to multiple abiotic stresses revealed the functional diversity of BnaCYP450 family in B. napus. This study gave a basic understanding of CYP450 genes in B. napus and provides multiple core BnaCYP450 genetic resources for improving plant resistance to multiple abiotic stresses.

Understanding the genetic diversity and origin of plantations will support the genetic monitoring and provenance selection in restoration projects and help to enhance the adaptation and resilience of plantation forests under climate change. However, information on the origin and genetic variation for plantations with native tree species is inadequate. Taiwania cryptomerioides Hayata is a threatened tree species and has been used as an important tree species for plantation in montane areas of South China. Information on the genetic diversity and origin of the existing Taiwania plantations is needed to facilitate their further development. In this study, using 12 nuclear microsatellite markers, the genetic diversity and structure were investigated in seven previously assumed natural populations and 19 plantation populations of T. cryptomerioides in South China. The Taiwania plantations showed lower genetic diversity and closer genetic distance than natural populations, indicating that most plantations were established with a narrow genetic basis. The results revealed that the majority of Taiwania plantations originated from two areas of the species’ natural distribution: northwestern Yunnan and southeastern Guizhou. Interestingly, we found that part of plantations in western Yunnan might represent unique genetic resources. Finally, conservation strategies of germplasm resources and genetic guidelines for seed sourcing of T. cryptomerioides are recommended. This study could facilitate the sustainable development of Taiwania plantations and also serve as a valuable reference for plantation management in China and elsewhere. We suggest that genetic monitoring of plantation forests should be considered in future restoration programs.

Boron (B) is an important limiting factor for plant growth and yield in saline soils, but the underlying molecular mechanisms remain poorly understood. In this study, we found that appropriate B supply obviously complemented rapeseed (Brassica napus L.) growth under salinity accompanied by higher biomass production and less reactive oxygen species accumulation. Determination of Na+ content in shoots and roots indicated that B significantly repressed root-to-shoot Na+ translocation, and non-invasive micro-tests of root xylem sap demonstrated that B increased xylem Na+ unloading in the roots of rapeseed plants under salinity. Comparative transcriptomic profiling revealed that B strongly upregulated BnaHKT1s expression, especially BnaA2.HKT1, in rapeseed roots exposed to salinity. In situ hybridizations analysis showed that BnaA2.HKT1 was significantly induced in root stelar tissues by high B (HB) under salinity. Green fluorescent protein and yeast heterologous expression showed that BnaA2.HKT1 functioned as a plasma membrane-localized Na+ transporter. Knockout of BnaA2.HKT1 by CRISPR/Cas9 resulted in hypersensitive of rapeseed plants to salinity even under HB condition, with higher shoot Na+ accumulation and lower biomass production. By contrast, overexpression of BnaA2.HKT1 ameliorated salinity-induced growth inhibition under B deficiency and salinity. Overall, our results proposed that B functioned as a positive regulator for the rapeseed growth and seed production under salt stress through facilitating BnaA2.HKT1-mediated root xylem Na+ unloading. This study may also provide an alternative strategy for the improvement of crop growth and development in saline soils.

Allotetraploid rapeseed ( Brassica napus L.) is highly susceptible to salt stress, a worldwide limiting factor that causes severe losses in seed yield. Genetic variations in the resistance against salt stress found in rapeseed genotypes emphasizes the complex response architecture. Westar is ubiquitously used as a major transgenic receptor, and ZS11 is widely grown as a high production and good quality cultivar. In this study, Westar was identified to outperform than ZS11 under salt stress. Through cell component isolation, non-invasive micro-test, X-ray energy spectrum analysis, and ionomic profiling characterization, pectin demethylation was found to be a major regulator for differential salt resistance between Westar and ZS11. Integrated analyses of genome-wide DNA variations, differentially expression profiling, and gene co-expression network identified BnaC9.PME47 , encoding pectin methyl esterase, as a positive regulator mainly responsible for salt stress resistance. BnaC9.PME47 , located in two reported QTLs regions for salt resistance, was strongly induced by salt stress and localized on the cell wall. Natural variation of the promoter regions conferred higher expression of BnaC9.PME47 in Westar than in other salt-sensitive rapeseed genotypes. Loss-of-function of AtPME47 resulted in the hypersensitivity of Arabidopsis plants to salt stress. This study facilitates a more comprehensive understanding of the differential morpho-physiological and molecular responses to salt stress and abundant genetic diversity in rapeseed genotypes, and the integrated multiomics analyses provide novel insights regarding the rapid dissection of quantitative trait genes responsible for nutrient stresses in plant species with complex genomes.

Rapeseed is extremely sensitive to NH4+ toxicity. Phytohormones have been implicated in plant root response to NH4+ toxicity, but whether they are involved in shoot response to NH4+ toxicity remains unclear. Through physiological and metabolic analyses, we found NH4+ toxicity increased SA accumulation through accelerating the transformation of SA precursor. Meanwhile, exogenous SA significantly enhanced NH4+ toxicity symptom in rapeseed shoot. Transcriptomic analysis showed that NH4+ toxicity enhanced the expression of the genes related to SA biosynthesis, transport, signaling, and conversion. SA treatment significantly enhanced shoot NH4+ concentrations through decreasing the activities of nitrate reductase and glutamine synthase in NH4+ treated plants. Plants treated with a SA biosynthesis inhibitor ABT relieved NH4+ toxicity symptom. Further, SA induced putrescine (Put) accumulation, leading to an enhanced Put/[spermidine (Spd) + spermine (Spm)] ratio in NH4+ treated rapeseed, while the opposite was true for ABT. Exogenous Put and its inhibitor DFMA aggravated and alleviated NH4+ toxicity of rapeseed shoot, respectively. In conclusion, NH4+ led to SA accumulation, thereafter resulting increased Put concentration and Put/(Spd+Spm) ratio, which is key for the shoot toxicity of NH4+ nutrition in rapeseed. This study provided new insights into the toxicity mechanism and alleviating strategies of plants NH4+ nutrition.

Soil bacterial communities are intricately linked to ecosystem functioning, and understanding how communities assemble in response to environmental change is ecologically significant. Little is known about the assembly processes of bacteria communities across agro-ecosystems, particularly with regard to their environmental adaptation. To gain further insights into the microbial community characteristics of agro-ecosystems soil in the Panxi area of Sichuan Province and explore the key environmental factors driving the assembly process of the microbial community, this study conducted field sampling in major farmland areas of Panxi area and used Illumina MiSeq high-throughput sequencing technology to conduct bacterial sequencing. Soil organic matter (SOM), alkali-hydrolyzed nitrogen (AN), available phosphorus (AP), available potassium (AK) and other environmental factors were determined. The membership function method and principal component analysis method were used to evaluate the fertility of the soil. The results revealed minimal differences in alpha diversity index among samples with different comprehensive fertility indices, while NMDS analysis showed that community differences between species were mainly reflected in high fertility and low fertility (R: 0.068, p: 0.011). Proteobacteria, Acidobacteria and Actinobacteria were the main types of microbial communities, accounting for more than 60% of the relative abundance. Proteobacteria accounted for a higher proportion in the high fertility samples, while Acidobacteria and Actinobacteria accounted for a higher proportion in the middle and low fertility samples. Both the neutral theoretical model and zero model analysis showed that the microbial communities in tobacco-planting soil with different comprehensive fertility indices presented a random assembly process. With the increase in environmental distance difference, the diversity of the microbial community in medium and low-fertility soil also increased, but there was no significant change in high-fertility soil. Redundancy analysis showed that pH and SOM were the key factors affecting microbial community composition. The results of this study can provide a theoretical reference for the study of environmental factors and microbial communities in tobacco-growing soil.

Wheat plants are ubiquitously simultaneously exposed to salinity and limited iron availability caused by soil saline-alkalisation. Through this study, we found that both low Fe and NaCl severely inhibited the growth of seminal roots in wheat seedlings; however, sufficient Fe caused greater growth cessation of seminal roots than low Fe under salt stress. Low Fe improved the root meristematic division activity, not altering the mature cell sizes compared with sufficient Fe under salt stress. Foliar Fe spray and split-root experiments showed that low Fe-alleviating the salinity-induced growth cessation of seminal roots was dependent on local low Fe signals in the roots. Ionomics combined with TEM/X-ray few differences in the root Na+ uptake and vacuolar Na+ sequestration between two Fe levels under salt stress. Phytohormone profiling and metabolomics revealed salinity-induced overaccumulation of ACC/ethylene and tryptophan/auxin in the roots under sufficient Fe than under low Fe. Differential gene expression, pharmacological inhibitor addition and the root growth performance of transgenic wheat plants revealed that the rootward auxin efflux and was responsible for the low Fe-mediated amelioration of the salinity-induced growth cessation of seminal roots. Our findings will provide novel insights into the modulation of crop root growth under salt stress.

Abstract Background: Brassica napus is an important oil crop in China and has a great demand for nitrogen. Amino acid transporters (AAT) play a key role in amino acid absorption and transport in plants. However, the AAT family genes have not been reported in Brassica napus so far.Results: In this study, genome-wide analysis identified 203 AAT members in Brassica napus genome. Based on phylogenetic and synteny analysis, BnaAATs were classified into twelve groups. The members in the same subgroups showed that similar physiochemical characteristics, intron/exon and motif patterns. By evaluating cis-acting regulatory elements (CREs) in the promoters, we identified some cis-acting regulatory elements (CREs) related to hormone, stresses and plant development. Darwin’s evolutionary analysis indicated that BnaAATs might have experienced strong purifying selection pressure. The BnaAAT gene family in Brassica napus may have undergone gene expansion, the chromosomal location of BnaAATs indicated that whole genome replication or segmental replication may play a major driving role. Differential expression pattern of BnaAATs under nitrate limitation, phosphate shortage, potassium shortage, boron stress, boron toxicity, cadmium toxicity, ammonium excess, and salt stress conditions indicated that they were responsive to different nutrient stresses. Conclusions: In summary, these findings provide a comprehensive survey of the BnaAAT genes family and lay a foundation for the further functional analysis of family members. Transcriptome analysis identified genes that responded to stresses, which laid a foundation for the genetic improvement in rapeseed nutrient stress resistance.

Cadmium (Cd) is a highly toxic heavy metal that readily enters cereals, such as wheat, via the roots and is translocated to the shoots and grains, thereby posing high risks to human health. However, the vast and complex genome of allohexaploid wheat makes it challenging to understand Cd resistance and accumulation. In this study, a Cd-resistant cultivar of wheat, 'ZM1860', and a Cd-sensitive cultivar, 'ZM32', selected from a panel of 442 accessions, exhibited significantly different plant resistance and grain accumulation. We performed an integrated comparative analysis of the morpho-physiological traits, ionomic and phytohormone profiles, genomic variations, transcriptomic landscapes, and gene functionality in order to identify the mechanisms underlying these differences. Under Cd toxicity, 'ZM1860' outperformed 'ZM32', which showed more severe leaf chlorosis, poorer root architecture, higher accumulation of reactive oxygen species, and disordered phytohormone homeostasis. Ionomics showed that 'ZM32' had a higher root-to-shoot translocation coefficient of Cd and accumulated more Cd in the grains than 'ZM1860'. Whole-genome re-sequencing (WGS) and transcriptome sequencing identified numerous DNA variants and differentially expressed genes involved in abiotic stress responses and ion transport between the two genotypes. Combined ionomics, transcriptomics, and functional gene analysis identified the plasma membrane-localized heavy metal ATPase TaHMA2b-7A as a crucial Cd exporter regulating long-distance Cd translocation in wheat. WGS- and PCR-based analysis of sequence polymorphisms revealed a 25-bp InDel site in the promoter region of TaHMA2b-7A, and this was probably responsible for the differential expression. Our multiomics approach thus enabled the identification of a core transporter involved in long-distance Cd translocation in wheat, and it may provide an elite genetic resource for improving plant Cd resistance and reducing grain Cd accumulation in wheat and other cereal crops.

脯氨酸积累是植物在生物和非生物胁迫下的一种重要的代谢适应性机制。吡咯啉-5-羧酸合成酶（P5CS）、吡咯啉-5-羧酸还原酶（P5CR）酶、脯氨酸脱氢酶（PDH）、吡咯啉-5-羧酸脱氢酶（P5CDH）是依赖谷氨酸的脯氨酸生物合成途径中的关键酶。油菜是世界上重要的油料作物,在油菜生长发育过程中,其时常遭受各类生物和非生物胁迫。然而迄今为止,在异源四倍体油菜中缺乏关于这些脯氨酸代谢基因家族的系统分析报道。本研究利用甘蓝型油菜‘中双11’基因组注释信息,分别鉴定到上述10个BnaP5CSs、6个BnaP5CRs、8个BnaPDHs以及3个BnaP5CDHs基因。这些基因家族在系统发育上分为不同的进化分支,同一亚组中的成员具有相似的理化特性、基因/蛋白质结构和保守的基序。进化压力分析表明,这些基因均遭受了强烈的纯化选择。启动子区的顺式作用元件分析揭示了油菜上述4类基因家族之间均存在共同的和特异的转录调控机制。本研究分别对‘中双11’油菜幼苗进行盐胁迫、低钾、低磷以及铵毒胁迫处理,分别取地上部及根部进行转录组测定与分析。结果显示,脯氨酸合成相关基因的表达水平在上述4种胁迫下普遍上调,而调控脯氨酸降解基因的表达水平则在盐胁迫和低磷胁迫情况下调;基因共表达分析显示BnaC4.P5CS1a、BnaA5.P5CS1等基因可能在脯氨酸介导的油菜逆境响应网络中发挥核心作用。本研究通过脯氨酸代谢基因家族的生物信息学鉴定以及多种非生物逆境下的转录特征分析,将为深入研究脯氨酸介导的逆境抗性提供理论依据,也将为脯氨酸介导油菜非生物胁迫抗性的遗传改良提供优异的基因资源。

During storage, transportation and sales, the deterioration of the tomato ripening fruit mainly caused by mechanical damage and microbial infection results in great economic losses. There is growing interest in fruit ripening studies and postharvest quality improvement to further enhance its already high economic value. Fruit ripening are coordinated by a complex network of endogenous and exogenous factors, including the phytohormone ethylene and abscisic acid, transcription factors, non-coding RNA, epigenetic modification, and environmental factors. However, the studies on RING-finger proteins involved in fruit development and ripening have not been reported. In this study, SlCHYR1, encoding a RING and CHY zinc finger domain-containing protein, which shows high expression levels in fruit was isolated and studied in tomato. Overexpression of SlCHYR1 with a fruit-specific promoter originating from pineapple leads to accelerated fruit ripening, reduced shelf life and repressed chlorophyll accumulation in tomato fruit. Further investigation indicate that SlCHYR1 promotes tomato fruit ripening through abscisic acid and ethylene production and signaling. This work provides novel insights into the regulation of fruit development and ripening by ZFPs (Zinc finger proteins), and would contribute to the improvement of quality and shelf life of tomato.

The GARP genes are plant-specific transcription factors (TFs) and play key roles in regulating plant development and abiotic stress resistance. However, few systematic analyses of GARPs have been reported in allotetraploid rapeseed (Brassica napus L.) yet. In the present study, a total of 146 BnaGARP members were identified from the rapeseed genome based on the sequence signature. The BnaGARP TFs were divided into five subfamilies: ARR, GLK, NIGT1/HRS1/HHO, KAN, and PHL subfamilies, and the members within the same subfamilies shared similar exon-intron structures and conserved motif configuration. Analyses of the Ka/Ks ratios indicated that the GARP family principally underwent purifying selection. Several cis-acting regulatory elements, essential for plant growth and diverse biotic and abiotic stresses, were identified in the promoter regions of BnaGARPs. Further, 29 putative miRNAs were identified to be targeting BnaGARPs. Differential expression of BnaGARPs under low nitrate, ammonium toxicity, limited phosphate, deficient boron, salt stress, and cadmium toxicity conditions indicated their potential involvement in diverse nutrient stress responses. Notably, BnaA9.HHO1 and BnaA1.HHO5 were simultaneously transcriptionally responsive to these nutrient stresses in both hoots and roots, which indicated that BnaA9.HHO1 and BnaA1.HHO5 might play a core role in regulating rapeseed resistance to nutrient stresses. Therefore, this study would enrich our understanding of molecular characteristics of the rapeseed GARPs and will provide valuable candidate genes for further in-depth study of the GARP-mediated nutrient stress resistance in rapeseed.

BACKGROUND:Plants worldwide are often stressed by low Fe availability around the world, especially in aerobic soils. Therefore, the plant growth, seed yield, and quality of crop species are severely inhibited under Fe deficiency. Fe metabolism in plants is controlled by a series of complex transport, storage, and regulatory mechanisms in cells. Allohexaploid wheat (Triticum aestivum L.) is a staple upland crop species that is highly sensitive to low Fe stresses. Although some studies have been previously conducted on the responses of wheat plants to Fe deficiency, the key mechanisms underlying adaptive responses are still unclear in wheat due to its large and complex genome.RESULTS:Transmission electron microscopy showed that the chloroplast structure was severely damaged under Fe deficiency. Paraffin sectioning revealed that the division rates of meristematic cells were reduced, and the sizes of elongated cells were diminished. ICP-MS-assisted ionmics analysis showed that low-Fe stress significantly limited the absorption of nutrients, including N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and B nutrients. High-throughput transcriptome sequencing identified 378 and 2,619 genome-wide differentially expressed genes (DEGs) were identified in the shoots and roots between high-Fe and low-Fe conditions, respectively. These DEGs were mainly involved in the Fe chelator biosynthesis, ion transport, photosynthesis, amino acid metabolism, and protein synthesis. Gene coexpression network diagrams indicated that TaIRT1b-4A, TaNAS2-6D, TaNAS1a-6A, TaNAS1-6B, and TaNAAT1b-1D might function as key regulators in the adaptive responses of wheat plants to Fe deficiency.CONCLUSIONS:These results might help us fully understand the morpho-physiological and molecular responses of wheat plants to low-Fe stress, and provide elite genetic resources for the genetic modification of efficient Fe use.