As a vital technology of renewable-nitrogen-fertilizer production, the conventional membrane distillation for ammonia nitrogen recovery from wastewater suffers from two challenges including high energy consumption and low product value, thus necessitating to develop a more efficient technology. Herein, a novel air gap membrane absorption (AGMA) structure was proposed to achieve superefficient ammonia nitrogen recovery and crystallization. To minimize heat loss and water transfer, AGMA was designed as an adiabatic air gap module (thickness=3 mm). The introduction of air gap structure enabled the feed side and the permeate side to maintain constant temperature, where the overall heat flux of AGMA process was 1019 W/m2 lower than that of the process without air gap. Meanwhile, the water flux (from the permeate side to the feed side) reached to 1.27 kg/(m2 h), and the overall mass transfer coefficient of ammonia (from the feed side to the permeate side) maintained at 2.38×10-6 m/s, promoting the concentration and crystallization of permeate solution. Importantly, the AGMA process yielded an ultrahigh ammonia separation factor (>200), which exceeded these of typical membrane-based ammonia recovery technologies. Moreover, the AGMA system could stably achieve the recovery of pure ammonium salt crystals in the 60-hour cyclic experiment using liquid digestate as feed solution. Economic analysis confirmed that this system exhibited low energy consumption of approximately 64.35 kJ/mol-NH3 and a low treatment cost of $2.01/m3-liquid digestate. These results underscore the great potential of the AGMA structure for high-efficiency and low-cost ammonia nitrogen recovery.

Wheat (Triticum aestivum L.) is considered one of the most important cereals globally, contributing significantly to the human population’s caloric and protein requirements. Therefore, ensuring a sufficient yield of wheat for global consumption plays a significant role in maintaining food security in different parts of the world. With increasing demand and dwindling production capacity, due to increasingly uncertain growing conditions, projections indicate that there should be an upswing of 60–70% in wheat productivity by 2050 to fulfill the requirement. However, drought represents the most significant and widespread abiotic limitation to global wheat production, currently resulting in approximately 10% yield losses worldwide. Furthermore, each additional 1 °C increase in temperature is anticipated to decrease staple calorie production by 4.4%. The factors contributing to drought in wheat, as well as its impact on the plant’s biochemical, physiological, and morphological structures, include altered rainfall patterns, elevated atmospheric CO2 levels, increased temperatures, hot and dry winds, and restricted soil water availability. These factors initiate a series of morphological, physiological, and biochemical disruptions that hinder wheat growth and productivity. Drought impact on wheat starts at biochemical levels through reactive oxygen species (ROS) generation and degradation of chlorophylls, and tolerance to stress is influenced by a polygenic system where numerous genes contribute minor effects and interact significantly with environmental factors transitioning to osmoprotectants. At the physiological level, drought alters the water content in the plant body, leading to reduced net photosynthetic rates, stomatal conductance, transpiration rates, and water utilization efficiency. At the morphological level, drought impacts all kinds of structures such as roots, shoots, leaves and reproductive parts. To counter these effects, wheat develops a set of tolerant mechanisms called drought escape, avoidance and tolerance. An increase in trichomes and leaf waxes, alteration of root–shoot ratios, the staying green phenomenon, production of stress proteins like proline, activity of enzymes including superoxide dismutase (SOD), ascorbate peroxidase, catalase, etc., osmotic adjustment, abscisic acid (ABA) accumulation, expression of dehydration proteins called dehydrin, etc., contribute towards drought tolerance. This comprehensive review investigates the intricate interactions between drought and various wheat genotypes, emphasizing their substantial impacts on plant physiology, biochemistry, growth dynamics, and grain yield. Additionally, this review assesses a variety of genetic and biotechnological strategies aimed at enhancing the resilience of wheat genotypes to drought stress. By integrating recent research findings with practical applications, this review provides a detailed framework for improving the adaptive capacity of wheat plants to withstand the escalating threats of drought stress, thereby supporting sustainable wheat production in a changing climate. Addressing drought stress through genetic and biotechnological management practices is crucial for maintaining wheat productivity.

The huge and complex genome of bread wheat (AABBDD, 2n = 6x = 42) results in gene family expansion, thereby characterizing the core member is indispensable for deciphering the molecular basis of differential salt tolerance between genotypes, further for breeding salt-resilient varieties. In this study, we compared physiological, ionomic, genomic, and transcriptomic landscapes of two allohexaploid wheat accessions, salt-tolerant (H467) and salt-sensitive (L735), under 200 mM NaCl stress. H467 retained more Na+ in roots and accumulated less Na+ in shoots than L735, which maintaining weaker photosynthetic efficiency and chloroplast integrity. Salt-tolerant H467 and sensitive L735 exhibit pronounced structural genomic divergence, including millions of SNPs and InDels predominantly in intergenic regions, as well as numerous structural variants and copy number variations, which likely underlie their contrasting responses to salt stress. Transcriptome analysis revealed that TaHKT8-4D, a plasma membrane-localized Na+ transporter, was specifically and strongly induced in roots of H467 under salt stress. Co-expression gene network analysis placed TaHKT8-4D in a module negatively correlated with shoot Na+ content. Heterologous expression demonstrated that TaHKT8-4D possesses Na+ transport activity, leading to Na+ overaccumulation and growth inhibition of yeast cells under salt stress. In contrast, L735 showed upregulation of chlorophyll degradation and senescence-associated genes, correlating with severe leaf chlorosis and photosystem II impairment. Our findings uncover a mechanism where root-specific induction of TaHKT8-4D restricts Na+ translocation to shoots, thereby protecting photosynthetic tissues from ion toxicity and premature senescence, making it a promising candidate for genetic improvement of salt tolerance in wheat breeding programs.

Potassium (K) deficiency is a major global constraint compromising crop growth, stress tolerance, quality, and yield. Nevertheless, the biological basis of adaptive responses to K deprivation remains elusive in crops with complex genomic architectures, particularly allotetraploid rapeseed (Brassica napus L.). Integrated shoot performance and root architecture, leaf ultrastructure, ionomics, phytohormone profiles, comparative genome-wide gene expression profiling, high-resolution metabolite fingerprints, and weighted network analysis were combined to dissect the morpho-physiological, molecular, and metabolic responses of rapeseed plants to K deficiency. In this study, our investigation revealed that chlorotic leaf performance, decreased photosynthesis capacity, retarded root growth, excessive reactive oxygen species and abscisic acid accumulation, and disordered Fe and Mg ion homeostasis in the rapeseed plants grown under low K stress. Gene ontology and Kyoto Encyclopedia of Genes and Genomes of differentially expressed genes and differentially abundant metabolites coordinated reprogramming of critical pathways involving ion uptake and transport, starch and sucrose metabolism, amino acid metabolism, and phytohormone signaling transduction. Core K transporters from the multicopy family genes, alongside novel candidate genes (e.g. those encoding cuticular wax biosynthesis) and metabolites (e.g. lipids) were proposed as promising regulators for the adaptative responses of rapeseed plants to K deficiency. These findings establish a holistic framework connecting physiological manifestations with transcriptional-metabolic reprogramming under K deficiency, while proposing strategic targets for precision K management in rapeseed cultivation.

Cadmium (Cd) contamination in bread wheat threatens global food security and crop sustainability. Karrikin (KAR), a newly identified phytohormone exhibiting established growth-promoting effects in crops, has not yet been mechanistically defined in Cd detoxification pathways. This study revealed that additional nanomolar KAR mitigated Cd toxicity through dual mechanisms: inhibiting Cd uptake and enhancing stress resilience. Exogenous KAR application increased shoot and root biomass by 44.5 % and 34.7 %, respectively, under Cd toxicity while reducing tissue Cd concentrations by 39.1 %-41.5 % without disturbing essential micronutrient homeostasis. Integrative physiological and transcriptomic analyses demonstrated that KAR suppressed critical metal transporters (COPT3, ATX1 among others), restricting Cd influx. KAR preserved photosynthetic efficiency by maintaining chlorophyll content and stabilizing photosystem proteins. Mechanistically, KAR balanced redox homeostasis through dual ROS modulation - decreasing root H2O2 production by 26.0 % while elevating antioxidant enzyme (SOD, APX) activities in both roots and shoots. KAR modulated phytohormonal crosstalk by antagonizing jasmonic acid and brassinosteroid biosynthesis while paradoxically activating their downstream regulators, suggesting compensatory signaling rewiring. Promoter motif enrichment analysis identified MYB, MYC and G-box transcription factors as central regulators governing KAR-mediated Cd detoxification networks. These findings establish the novel role of nanomolar KAR in concurrently reducing Cd accumulation and improving stress resilience of bread wheat, proposing an eco-friendly phytomanagement strategy for heavy metal-contaminated agrosystems.

The tonoplast-localized transporter TaTPK1-5D, interacting with TaCIPK23-4D , enhances low K⁺ tolerance in wheat by promoting vacuolar K⁺ efflux, providing a key genetic target for improving K⁺-use efficiency in breeding. Bread wheat (Triticum aestivum L.) serves as a staple food for more than one-third of the global population, and potassium (K+) is critical for wheat yield and quality. However, the molecular mechanisms underlying wheat survival under low-K+ conditions remain poorly understood. In this study, a phenotypic screening of 712 wheat accessions identified a low-K+ sensitive genotype (H735) and a low-K+ tolerant genotype (H467, namely Zhengmai 136). Measurements of K+ concentration and non-invasive micro-test technology revealed that the differential tolerance between the two genotypes was not attributable to root K+ uptake capacity, but rather to a higher vacuolar K+ efflux rate in H467 compared to H735. Through transcriptomic-assisted differential expression and co-expression network analysis, a tonoplast-localized K⁺ efflux transporter, TaTPK1-5D, was identified as a key candidate underlying differential low-K⁺ tolerance in wheat. Functional disruption of TaTPK1-5DH467, but not TaTPK2-3DH467/2-4DH467/3-5DH467, significantly reduced both low-K+ tolerance and vacuolar K+ efflux in H467. High TaTPK1-5D expression was consistently observed in several other K+-efficient wheat accessions. Importantly, yeast two-hybrid screening, bimolecular fluorescence complementation, and pull-down assays demonstrated that TaTPK1-5D interacted with the protein kinase TaCIPK23-4D. Functional disruption of TaCIPK23-4D led to dramatic sensitivity to low-K+ stress. These findings establish TaTPK1-5D as a major vacuolar K+ efflux transporter facilitating subcellular K+ remobilization under low-K+ conditions.

Vegetable waste management and the creation of peat-free seedling substrates pose significant challenges to the sustainability of the modern vegetable industry. This study investigated the use of cabbage harvest residue (CHR) as a peat substitute in substrates through biochar-enhanced co-composting with spent mushroom residue (SMS). Various biochar dosages (0 % (CK), 2.5 % (BC2.5), 5.0 % (BC5.0) and 10 % (BC10)) were tested to evaluate their effects on the composting process, quality of the end-products, and application potential as peat substitutes. Results indicated that biochar, especially at dosages of 5.0 % and 10 %, enhanced moisture loss, humification, and compost quality. The highest peak temperature (67.3 degrees C), moisture reduction (similar to 30 %), carbon loss (similar to 50 %), seed germination index (GI, 199 %), humic substance content (14.5 %), and degree of humification were observed in BC10. Additionally, biochar treatments led to improvements in the structural composition and co-occurrence relationships within the microbial community. Substrates made from compost, vermiculite, and perlite exhibited excellent physicochemical properties and superior seedling growth performance compared to commercial substrates. Notably, BC2.5 emerged as the most optimal peat substitute, demonstrating significant enhancement in shoot height (6 %-88 %), thickness (4 %-113 %), and strong seeding index (SEI) (24 %-264 %). Overall, biochar-enhanced co-composting of CHR and SMS offers a promising sustainable solution for the modern vegetable industry.

The molecular mechanisms regulating seed vigor have attracted significant attention. This study confirmed the expression of OsPSK5, a gene encoding the phytosulfokine (PSK-α) precursor, regulates seed vigor in rice. Subcellular localization analysis showed that OsPSK5 was localized in the Golgi apparatus. Compared with wild-type rice, grain size and seed vigor were significantly decreased and reactive oxygen species (ROS) levels were elevated in ospsk5 mutants, but no significant differences of these traits were observed in OsPSK5-overexpression lines. Complementation of the ospsk5-1 mutant with OsPSK5 restored seed vigor to the wild-type level. The endogenous PSK content of ospsk5-1 seeds was significantly lower, while that in seeds of ospsk5-2 null mutant, OsPSK5-overexpression lines, and complementation lines were either equivalent to or significantly higher than that of wild-type seeds. Additionally, exogenous PSK-α treatment markedly promoted seed viability and callus induction in ospsk5-1 mutant seeds. Transcriptome and metabolome assays revealed that differential expression of OsPSK5 resulted in the differential expression of genes related to the biosynthesis and catabolism of cytokinins, gibberellins, abscisic acid, and polyphenolic compounds, leading to the levels of these secondary metabolites to vary between seeds of different genotypes. As a result, the expression of OsPSK5 may involve in rice seed vigor through modulating the biosynthesis and metabolism of PSK-α, other plant hormones, polyphenols, and ROS homeostasis etc.

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.

Plant-specific TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) proteins play critical roles in plant development and stress responses; however, their functions in chrysanthemum (Chrysanthemum morifolium) have not been well-studied. In this study, we isolated and characterized the chrysanthemum TCP transcription factor family gene CmTCP13, a homolog of AtTCP13. This gene encoded a protein harboring a conserved basic helix–loop–helix motif, and its expression was induced by salinity stress in chrysanthemum plants. Subcellular localization experiments showed that CmTCP13 localized in the nucleus. Sequence analysis revealed the presence of multiple stress- and hormone-responsive cis-elements in the promoter region of CmTCP13. The heterologous expression of CmTCP13 in Arabidopsis plants enhanced their tolerance to salinity stress. Under salinity stress, CmTCP13 transgenic plants exhibited enhanced germination, root length, seedling growth, and chlorophyll content and reduced relative electrical conductivity compared with those exhibited by wild-type (WT) plants. Moreover, the expression levels of stress-related genes, including AtSOS3, AtP5CS2, AtRD22, AtRD29A, and AtDREB2A, were upregulated in CmTCP13 transgenic plants than in WT plants under salt stress. Taken together, our results demonstrate that CmTCP13 is a critical regulator of salt stress tolerance in plants.

The holly Ilex dabieshanensis K. Yao & M. B. Deng, a tree endemic to the Dabieshan Mountains region in China, is a commonly used landscaping plant. Like other crops, its growth is affected by salt stress. The molecular mechanism underlying salt tolerance in holly is still unclear. In this study, we used NaCl treatment and RNA sequencing (RNA-seq) at different times to identify the salt stress response genes of holly. A total of 4775 differentially expressed genes (DEGs) were identified. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of the DEGs obtained at different salt treatment times (3, 6, 9, 12, and 24 h), as compared to control (ck, 0 h), showed that plant hormone signal transduction and carotenoid biosynthesis were highly enriched. The mechanism by which holly responds to salt stress involves many plant hormones, among which the accumulation of abscisic acid (ABA) and its signal transduction may play an important role. In addition, ion homeostasis, osmotic metabolism, accumulation of antioxidant enzymes and nonenzymatic antioxidant compounds, and transcription factors jointly regulate the physiological balance in holly, providing important guarantees for its growth and development under conditions of salt stress. These results lay the foundation for studying the molecular mechanisms of salt tolerance in holly and for the selection of salt-tolerant varieties.

Rapeseed (Brassica napus L.) is extremely sensitive to excessive NH4+ toxicity. There remains incomplete knowledge of the causal factors behind the growth suppression in NH4+-nourished plants, with limited studies conducted specifically on field crop plants. In this study, we found that NH4+ toxicity significantly increased salicylic acid (SA) accumulation by accelerating the conversion of SA precursors. Moreover, exogenous SA application significantly aggravated NH4+ toxicity symptoms in the rapeseed shoots. Genome-wide differential transcriptomic analysis showed that NH4+ toxicity increased the expression of genes involved in the biosynthesis, transport, signaling transduction, and conversion of SA. SA treatment significantly increased shoot NH4+ concentrations by reducing the activities of glutamine synthase and glutamate synthase in NH4+-treated rapeseed plants. The application of an SA biosynthesis inhibitor, ABT, alleviated NH4+ toxicity symptoms. Furthermore, SA induced putrescine (Put) accumulation, resulting in an elevated ratio of Put to [spermidine (Spd) + spermine (Spm)] in the NH4+-treated plants, while the opposite was true for ABT. The application of exogenous Put and its biosynthesis inhibitor DFMA induced opposite effects on NH4+ toxicity in rapeseed shoots. These results indicated that the increased endogenous SA contributed noticeably to the toxicity caused by the sole NH4+-N supply in rapeseed shoots. This study provided fresh perspectives on the mechanism underlying excessive NH4+-induced toxicity and the corresponding alleviating strategies in plants.

Integrated phenomics, ionomics, genomics, transcriptomics, and functional analyses present novel insights into the role of pectin demethylation-mediated cell wall Na+ retention in positively regulating salt tolerance in oilseed rape. Genetic variations in salt stress tolerance identified in rapeseed genotypes highlight the complicated regulatory mechanisms. Westar is ubiquitously used as a transgenic receptor cultivar, while ZS11 is widely grown as a high-production and good-quality cultivar. In this study, Westar was found to outperform ZS11 under salt stress. Through cell component isolation, non-invasive micro-test, X-ray energy spectrum analysis, and ionomic profile characterization, pectin demethylation-mediated cell wall Na+ retention was proposed to be a major regulator responsible for differential salt tolerance between Westar and ZS11. Integrated analyses of genome-wide DNA variations, differential expression profiling, and gene co-expression networks identified BnaC9.PME47, encoding a pectin methylesterase, as a positive regulator conferring salt tolerance in rapeseed. BnaC9.PME47, located in two reported QTL regions for salt tolerance, 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 several salt-sensitive rapeseed genotypes. Loss of function of AtPME47 resulted in the hypersensitivity of Arabidopsis plants to salt stress. The integrated multiomics analyses revealed novel insights into pectin demethylation-mediated cell wall Na+ retention in regulating differential salt tolerance in allotetraploid rapeseed genotypes. Furthermore, these analyses have provided key information regarding the rapid dissection of quantitative trait genes responsible for nutrient stress tolerance in plant species with complex genomes.

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.

Common wheat (Triticum aestivum L.) is a global staple food, while nitrogen (N) limitation severely hinders plant growth, seed yield, and grain quality of wheat. Genetic variations in the responses to low N stresses among allohexaploid wheat (AABBDD, 2n = 6x = 42) genotypes emphasize the complicated regulatory mechanisms underlying low N tolerance and N use efficiency (NUE). In this study, hydroponic culture, inductively coupled plasma mass spectrometry, noninvasive microtest, high-performance liquid chromatography, RNA-seq, and bioinformatics were used to determine the differential growth performance, ionome and phytohormone profiles, and genome-wide expression profiling of wheat plants grown under high N and low N conditions. Transcriptional profiling of NPFs, NRT2s, CLCs, SLACs/SLAHs, AAPs, UPSs, NIAs, and GSs characterized the core members, such as TaNPF6.3-6D, TaNRT2.3-3D, TaNIA1-6B, TaGLN1;2-4B, TaAAP14-5A/5D, and TaUPS2-5A, involved in the efficient transport and assimilation of nitrate and organic N nutrients. The low-N-sensitivity wheat cultivar XM26 showed obvious leaf chlorosis and accumulated higher levels of ABA, JA, and SA than the low-N-tolerant ZM578 under N limitation. The TaMYB59-3D-TaNPF7.3/NRT1.5-6D module-mediated shoot-to-root translocation and leaf remobilization of nitrate was proposed as an important pathway regulating the differential responses between ZM578 and XM26 to low N. This study provides some elite candidate genes for the selection and breeding of wheat germplasms with low N tolerance and high NUE.

BACKGROUND:Plant growth and development are severely threatened by drought and salt stresses. Compared with structural genes, transcription factors (TFs) play more pivotal roles in plant growth and stress adaptation. However, the underlying mechanisms of sorghum adapting to drought and salt are insufficient, and systematic analysis of TFs in response to the above stresses is lacking.RESULTS:In this study, TFs were identified in sorghum and model plants (Arabidopsis thaliana and rice), and gene number and conserved domain were compared between sorghum and model plants. According to syntenic analysis, the expansion of sorghum and rice TFs may be due to whole-genome duplications. Between sorghum and model plants TFs, specific conserved domains were identified and they may be related to functional diversification of TFs. Forty-five key genes in sorghum, including four TFs, were likely responsible for drought adaption based on differently expression analysis. MiR5072 and its target gene (Sobic.001G449600) may refer to the determination of sorghum drought resistance according to small RNA and degradome analysis. Six genes were associated with drought adaptation of sorghum based on weighted gene co-expression network analysis (WGCNA). Similarly, the core genes in response to salt were also characterized using the above methods. Finally, 15 candidate genes, particularly two TFs (Sobic.004G300300, HD-ZIP; Sobic.003G244100, bZIP), involved in combined drought and salt resistance of sorghum were identified.CONCLUSIONS:In summary, the findings in this study help clarify the molecular mechanisms of sorghum responding to drought and salt. We identified candidate genes and provide important genetic resource for potential development of drought-tolerant and salt-tolerant sorghum plants.

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.

Brassica napus is an important oil crop in China and has a great demand for nitrogen nutrients. Cationic amino acid transporters (CAT) play a key role in amino acid absorption and transport in plants. However, the CATs family has not been reported in B. napus so far. In this study, genome-wide analysis identified 22 CAT members in the B. napus genome. Based on phylogenetic and synteny analysis, BnaCATs were classified into four groups (Group I-Group IV). The members in the same subgroups showed similar physiochemical characteristics and intron/exon and motif patterns. By evaluating cis-elements in the promoter regions, we identified some cis-elements related to hormones, stress and plant development. Darwin's evolutionary analysis indicated that BnaCATs might have experienced strong purifying selection pressure. The BnaCAT family may have undergone gene expansion; the chromosomal location of BnaCATs indicated that whole-genome replication or segmental replication may play a major driving role. Differential expression patterns of BnaCATs under nitrate limitation, phosphate shortage, potassium shortage, cadmium toxicity, ammonium excess and salt stress conditions indicated that they were responsive to different nutrient stresses. In summary, these findings provide a comprehensive survey of the BnaCAT family and lay a foundation for the further functional analysis of family members.

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.