Nitrogen (N) is essential for rapeseed growth, yet nitrogen use efficiency (NUE) in this crop remains low, partly because N stored in leaves is not efficiently remobilized before senescence and abscission. NAC transcription factors are central regulators of senescence and stress responses, but their roles in N remobilization in rapeseed remain insufficiently defined. Here, we investigated the role of BnaC6.NAC19 in regulating leaf senescence and N remobilization. The results showed that BnaC6.NAC19 was preferentially expressed in old leaves and siliques, and its expression was significantly induced by Low-N (LN) stress. Overexpression of BnaC6.NAC19 (OE lines) promoted leaf senescence, as evidenced by increased leaf yellowing, decreased SPAD values and chlorophyll contents, under LN conditions. Meanwhile, OE lines exhibited enhanced NUE and N remobilization efficiency, with higher 15N accumulation in young leaves and a higher rate of 15N loss from old leaves. Transcriptome analysis revealed that BnaC6.NAC19-OE was associated with increased expression of senescence-related genes, including BnaA7.ORE1 and BnaC2.PAO4, and N transport-related genes, including BnaA9.NRT1.7, BnaC5.NRT1.5, BnaA9.AAP1, and BnaC2.DUR3, under LN. Sand culture experiments demonstrated that OE lines had significantly higher seed biomass, seed N accumulation and nitrogen harvest index under LN supply, without a significant increase in total plant N accumulation. Together, these results indicate that BnaC6.NAC19 positively links LN-induced leaf senescence with N remobilization and improves N partitioning to developing sinks. BnaC6.NAC19 therefore represents a promising candidate for improving NUE in rapeseed.

Potassium deficiency is one of the key factors affecting crop yields. This study investigated the effects of low potassium stress on the growth of three barley varieties from physiological and biochemical indicators, transcriptomics and weighted gene co-enrichment analysis. Results indicate that low potassium treatment reduced potassium accumulation, plant height, root surface area, dry weight, and photosynthetic parameters in all barley varieties, thereby inhibiting barley growth. Significantly enhanced potassium transport coefficients in stems, along with increased H+,K+-ATPase activities, indicate that this enzyme plays a crucial role in alleviating potassium deficiency stress in barley. Transcriptome analysis indicates that low potassium treatment primarily affects hormone signal synthesis and transduction, antioxidant enzymes, and transcription factors. Differentially expressed genes are mainly involved in plant defense and immunity, metabolite and energy regulation, photosynthesis, carbohydrate and nitrogen metabolism, as well as hormone and developmental regulation. Through WGCNA analysis, 12 pivotal genes exhibiting strong interactions were identified in root-MEbrown, shoot-MEpink, and stem-MEturquoise. Five genes (LOC123407914, LOC123448799, tplb0006k10, NIASHv2043B04, NIASHv3101N17) belong to the same KEGG pathway: ko03040 (Splicosome), classified under the primary pathway category of Cellular Processes. These 12 genes maintain apical meristem activity and H+-K+-ATPase activity, regulate photosynthetic efficiency, maintain leaf width, ensure energy synthesis and function at the RNA helicase and nucleolar levels within the nucleus to ensure normal plant growth under low-potassium stress. Moreover, three of these genes may undergo alternative splicing events, and the effects of potassium deficiency on alternative splicing have been rarely reported. Further research on these genes may fill this gap.

Thinopyrum elongatum (2n = 4x = 28) harbors multiple valuable resistance genes and serves as a valuable genetic resource for wheat improvement. Yr1EL was primarily identified on chromosome arm 1EL of tetraploid Th. elongatum, conferring adult-plant resistance to stripe rust. To further map and utilize Yr1EL, we introduced chromosomal rearrangements by crossing the wheat–tetraploid Th. elongatum 1E(1D) substitution line and the T1BS·1EL translocation line with the common wheat Chinese Spring ph1b mutant. In total, eight wheat–Th. elongatum chromosome 1E structural variants were identified by in situ hybridization, the GenoBaits®WheatplusEE panel, and molecular markers. These variants include one large segment translocation, one terminal fragment deletion, one chromosome 1E insertion translocation, and five chromosome 1EL terminal small fragment translocations. Based on phenotyping and genotyping of these variant lines, Yr1EL was mapped to an approximately 20.91 Mb physical interval (532.45 to 553.35 Mb) on the distal long arm of chromosome 1E corresponding to the diploid Th. elongatum reference genome. Genetic analysis confirmed that stripe rust resistance was conferred by the Yr1EL locus with incomplete dominance. Five codominant molecular markers co-segregated with the Yr1EL locus and will facilitate marker-assisted selection. Furthermore, collinearity analysis showed that this interval is structurally conserved among Triticeae species, and 29 candidate genes potentially related to disease resistance were annotated. Those candidates included receptor-like proteins, kinases, nucleotide-binding and leucine-rich repeat receptors, and other disease resistance proteins. The adult-plant resistance gene Yr1EL expands the wheat disease-resistance gene pool and provides valuable germplasm for breeding durable stripe rust-resistant cultivars.

Deep-space conditions exert severe stress on plant genome stability, gene expression, epigenetic modification, and cell differentiation. In this study, multiomics analysis is used to observe changes in rice at the molecular and cellular levels after deep-space flight, including an increase in the frequency and types of mutations. While overall DNA methylation levels do not significantly change, CHG methylation levels present an increase that is correlated with DNA methylation responses. RNA presents significantly elevated m6A modification levels, which positively regulate gene expression. The proportion of mesophyll cells decreases, and 188 genes are identified as affecting the differentiation of mesophyll cells. Integrated multiomics analysis supports a hypothesis that the NAC family transcription factor suppressor of variation transmission 1 (SVT1) negatively regulates MAPK pathway genes, potentially influencing differentiation of cells harbouring mutations. Overall, this study comprehensively describes the molecular map of rice after deep-space flight and proposes a putative mechanism through which SVT1 may adapt to deep-space flight by inhibiting the differentiation of cells harbouring mutations.

Atmospheric nitrogen (N) deposition is altering global forest ecosystems, with nitrate rising to rival ammonium as a dominant N form, yet how leaf ontogeny orchestrates carbon-nitrogen (C-N) metabolic coordination under contrasting N forms remains poorly understood. We conducted a field experiment investigating the physiological and metabolic responses of young and old leaves of Chinese fir (Cunninghamia lanceolata) to ammonium and nitrate addition. Young leaves, functioning as active sinks, exhibited enhanced photosynthetic performance and growth-oriented N assimilation under N addition, with disproportionately stronger responses to nitrate. In contrast, old leaves, acting as source tissues, showed limited photosynthetic plasticity but accumulated higher non-structural carbohydrates and elevated N assimilation enzyme activities, particularly under nitrate addition. Phytohormone profiles supported this ontogenetic divergence, with young leaves showing higher auxin levels while old leaves exhibited increased abscisic acid and salicylic acid contents. Metabolomic analysis further revealed age-dependent reprogramming of amino acid metabolism, identifying key metabolites coordinating C-N balance. These findings demonstrate a leaf ontogeny-mediated spatial division of metabolic labor in Chinese fir, wherein old leaves function as metabolic buffers stabilizing whole-plant C-N homeostasis under fluctuating N supply, providing new insights into plantation responses to contrasting N deposition regimes.

Biodegradable plastics, due to their renewable origin and perceived environmental benefits, are increasingly considered promising alternatives to conventional plastic. However, whether they are indeed more environmentally friendly than traditional plastics in agricultural soils—particularly in terms of greenhouse gas (GHGs) emissions and nitrogen (N) losses—remains poorly supported by empirical evidence. To address this, we conducted a one-season pot experiment to investigate the effects of low-density polyethylene (LDPE) and polylactic acid (PLA) microplastics (MPs), applied at two concentrations (0.2% and 2% w/w), on soil GHGs emissions (CO2, CH4, and N2O), N losses (NH3 volatilization and inorganic N leaching) and microbial communities. Our results showed that both MP type and concentration significantly affected soil GHGs emissions and N dynamics. High-dose PLA (2%) markedly increased GHGs emissions, which can be attributed to the release of biodegradable carbon substrates that stimulated microbial respiration and promoted the formation of oxygen-limited microsites in soil. Although low-dose PLA (0.2%) also stimulated CO2 and CH4 emissions, it—together with 2% LDPE—significantly reduced N2O emissions, suggesting that MPs may regulate the balance between nitrification and denitrification processes by altering soil aeration and microbial activity. All MP treatments decreased NH3 volatilization by 28.2% to 44.3%, likely due to the sorption of NH4+ onto MP surfaces, which enhanced ammonium retention and reduced NH3 diffusion from soil. The 2% PLA treatment also showed a certain advantage in reducing nitrate leaching, potentially through enhanced microbial immobilization of mineral N stimulated by additional biodegradable carbon inputs, albeit at the cost of elevated GHGs emissions. Moreover, MPs altered the structure of soil bacterial and fungal communities. The 2% PLA treatment enriched Proteobacteria, while both 0.2% and 2% PLA treatments increased the relative abundance of Ascomycota. The significant correlations between microbial communities, GHGs emissions, and N losses indicate that MPs may regulate soil C and N cycling through microbially mediated pathways. Our findings demonstrate that biodegradable MPs are not inherently more environmentally benign than conventional plastics. Their ecological effects are concentration-dependent and involve complex microbial interactions. These insights provide a scientific basis for the environmental risk assessment and responsible use of biodegradable mulch films in agricultural systems.

While excessive nitrogen fertilizer application enhances crop yields, it does so at the expense of ecosystem health, making the enhancement of nitrogen use efficiency (NUE) an imperative for sustainable agriculture. This study investigates the mechanisms underlying the response to low nitrate (LN) stress in two Brassica juncea genotypes: a high-NUE (H158) and a low-NUE (L159), aiming to identify genetic resources for improved NUE. Hydroponic experiments revealed that H158 displayed enhanced antioxidant capacity, nitrogen assimilation, and nitrogen uptake efficiency (NUpE) under LN conditions relative to L159. Field trials corroborated these findings, with H158 demonstrating higher yields and greater agronomic nitrogen use efficiency (ANUE) across a gradient of nitrogen application rates. Genomic analysis identified 1,654 genes associated with NUE, including NIN-LIKE PROTEIN 4 (BjuB04.NLP4), whose G/C variants influenced transcriptional regulation and root-to-shoot ratio responses to nitrogen availability. Notably, BjuB04.NLP4-HAP2 (H158) was predominant in low-nitrogen soils, while BjuB04.NLP4-HAP1 (L159) was more common in high-nitrogen soils. Collectively, our findings uncover and characterize valuable genetic resources for breeding rapeseed varieties with enhanced NUE, providing both elite germplasm and functional molecular markers.

Understanding the tissue-specific physiological strategies for salt resilience is critical for crop improvement. This study characterized the differential responses of two spring wheat varieties, XC43 (tolerant) and XC40 (non-tolerant), to varying NaCl concentrations. Our results demonstrated that salinity suppressed plant growth in both varieties, XC43 effectively mitigated salt-induced growth inhibition through optimizing root morphology and sustaining photosynthetic efficiency. Mechanistically, XC43 maintained favorable ion homeostasis by restricting Na+ translocation to shoots while actively enhancing root K+ retention, thereby preserving high K+/Na+ ratios. Furthermore, XC43 deployed a root-dominant antioxidant defense system. Compared to XC40, XC43 exhibited significantly lower reactive oxygen species (ROS) accumulation and lipid peroxidation in roots. The maintenance of higher ascorbate peroxidase (APX), glutathione reductase (GR), dehydroascorbate reductase (DHAR) activities, and more favorable ascorbic acid/dehydroascorbic acid (AsA/DHA) and reduced glutathione/glutathione disulfide (GSH/GSSG) ratios provided superior redox protection in XC43 roots under moderate and high salinity. Principal component analysis validated that the salt resilience of XC43 was primarily driven by root-specific functional traits. Our findings revealed that the synergistic coordination between root K⁺ retention and the AsA-GSH cycle was a core determinant of salt tolerance, identifying root-mediated physiological integration as a pivotal target for breeding salt-resilient spring wheat varieties.

Fusarium head blight (FHB) threatens wheat production worldwide, and major-effect resistance sources remain limited. Elymus repens (2n=6x=42, StStStStHH) is a perennial Triticeae species with potential for wheat improvement. Here, we characterized the genomic constitution of the wheat-E. repens partial amphidiploid P1142-1-2, which shows strong FHB resistance. P1142-1-2 carries the complete wheat genome plus seven pairs of E. repens-derived chromosomes or chromosome fragments containing St chromatin from 1St to 7St. From crosses between P1142-1-2 and common wheat cv. Chuannong16, we identified two resistant derivative lines carrying either a 1StL isochromosome or a 1StL telosome. Genomic sequencing enabled the development of 17 1StL-specific PCR markers for precise detection of alien chromatin. Genetic analysis demonstrated that 1StL confers strong resistance to FHB in wheat. Diagnostic assays did not detect previously reported alien FHB resistance genes, indicating that 1StL carries a novel resistance locus, designated Fhb.Er-1StL. These materials and markers broaden the genetic basis of FHB resistance in wheat and provide useful resources for wheat improvement.

Cadmium (Cd) contamination in agricultural soils poses a significant threat to human health through the food chain. It is of great significance to address safe wheat production in Cd-contaminated agricultural soils. This study employed foliar spraying of ferulic acid (FA) in both hydroponic and field trials to investigate its potential in alleviating Cd toxicity and reducing Cd accumulation in wheat grains. Our findings revealed that FA application at 20 and 50 μM promoted plant growth, increased photosynthetic efficiency, and enhanced root tolerance to Cd by increasing mean root diameter, surface area, and root tip number, as well as enhancing antioxidant defense in roots. Especially, 20 μM FA foliar application significantly alleviated Cd-induced growth inhibition in seedlings and reduced grain Cd content by 66.3% compared to Cd-stressed alone. Mechanistically, FA downregulated the Cd transporter gene TaHAM2 to reduce Cd translocation from roots to shoots, while upregulated the Cd cellular compartment gene TaHAM3 to increase root Cd retention, of which 82.9% was sequestered in roots. During the grain-filling period in the field trial, FA application reduced Cd transport from roots to stems and stems to rachides, but enhanced Cd retention in rachides and roots. Additionally, FA downregulated the phloem Cd loading gene LCT1, limiting Cd allocation to bracts and grains, which in turn lowered the Cd content in the grains. Collectively, FA foliar application modulated Cd transport pathways by coordinately downregulating xylem and phloem transporter genes and enhancing root Cd retention capacity. These findings established FA as a promising strategy for Cd detoxification and reduced accumulation in crop grains through integrated physiological and molecular interventions. Overall, it holds potential for the future development of safe crop production in soils polluted with Cd.

Tetraploid Thinopyrum elongatum represents a valuable tertiary genetic pool for wheat improvement, harbouring numerous valuable agronomic traits. Our previous study identified Yr4EL, which confers all-stage resistance to stripe rust, was initially characterized from the tetraploid Th. elongatum chromosome (chr) 4E. To further fine-map Yr4EL, we generated 140 chr 4E structural variants using 60Co-γ irradiation, ph1b-induced, and double monosomy centromere breakage-fusion methods. All variants were cytogenetically characterized using genomic in situ hybridization and fluorescence in situ hybridization. These variants comprised 90 distinct chr 4E structural variants, including 20 fragment deletions, 14 large segment translocations, 19 whole-arm translocations, 10 chr 4E insertion translocations, and 27 terminal small fragment translocations. A high-resolution chr 4E physical map was constructed using molecular markers, delineated into 15 distinct bins. Subsequently, the diploid Th. elongatum reference genome (ASM1179987v1) enabled the fine-mapping of Yr4EL to a 1.8 Mb interval within the distal chr 4EL. Transcriptomic profiling, evolutionary analysis, and qRT-PCR validation identified five genes that might be the Yr4EL candidate. In addition, we deployed Yr4EL into susceptible common wheat varieties, conferring effective stripe rust resistance without a yield penalty, demonstrating its high potential value for wheat breeding programmes.

Wheat natural resistance-associated macrophage protein 3 (NRAMP3) are manganese (Mn) transporters that can also transport unwanted cadmium (Cd). However, their roles in regulating grain Cd concentration are unknown. Here, we functionally characterised TpNRAMP3-7A and TpNRAMP3-7B cloned from dwarf Polish wheat (Triticum polonicum L., AABB) in them of their expression patterns, transcript localisations, metal transport activities, and associated phenotypes. Both TpNRAMP3-7A and TpNRAMP3-7B were expressed in the epidermis, endodermis, and xylem parenchyma cells of roots, the xylem parenchyma cells and phloem region of nodes and leaf sheaths, and the phloem region of leaf blades. Knockout of TpNRAMP3-7A and/or TpNRAMP3-7B not only limited grain Cd concentration, but also reduced Cd uptake, root-to-shoot translocation, and shoot-to-grain distribution. They also limited grain Mn concentration by inhibiting shoot-to-grain Mn distribution when grown in the field (high-Mn concentration), and decreased Mn uptake and root-to-shoot translocation under low-Mn stress. Position 192F in TpNRAMP3 was the core amino acid determining Cd and Mn transport activity. These results provide a valuable guide and target gene for limiting Cd concentration in wheat grains.

BACKGROUND:Cassava (Manihot esculenta Crantz) stands as a pivotal food crop within tropical and subtropical regions. With its inherent drought-tolerant traits, cassava proves to be an ideal candidate for investigating drought tolerance mechanisms in staple crops. Although protein phosphatase 2C (PP2Cs) plays a critical role in drought stress responses in plants, the molecular mechanism of PP2Cs in cassava has yet to be elucidated. RESULTS:In this research, we cloned MePP2C26, a member of group A PP2Cs, which exhibited significant upregulation following treatments with mannitol, NaCl, and ABA. Arabidopsis transgenic lines overexpressing MePP2C26 exhibited reduced drought tolerance, with survival rates of 39 %, 37 %, and 39 % for OV2, OV3, and OV6 lines, respectively, compared to 53 % in wild-type (WT) and 52 % in vector control (VC) plants. Additionally, these transgenic lines showed altered responses to exogenous ABA, as MePP2C26 overexpression significantly alleviated ABA-induced inhibition of seed germination and root growth. These lines displayed elevated levels of malondialdehyde (MDA), ion leakage (IL), and reactive oxygen species (ROS), accompanied by reduced activities of catalase (CAT) and peroxidase (POD) as well as decreased proline accumulation compared to the wild type (WT) under drought stress conditions. Furthermore, MePP2C26 was shown to downregulate the expression of genes involved in the ABA signaling pathway (including AtSnRK2.6, ABF2, ABF3, RD26, and RD29B) under drought conditions, as evidenced by the transgenic line exhibiting consistently lower expression levels of these genes (despite their drought-induced upregulation in both transgenic and wild-type plants) compared to the WT. MePP2C26 was found to be localized in the nucleus and exhibited self-activation. Moreover, a number of MePYLs (MePYL1, MePYL4-9, MePYL11-13) were found to interact with MePP2C26 in the presence or absence of ABA. CONCLUSIONS:In conclusion, the results of this study indicate that MePP2C26 acts as a negative regulator in both drought tolerance and ABA signaling pathways in Arabidopsis.

It is of great significance to analyze the molecular mechanism of rice response to heavy ion irradiation and to mine its key response genes for food security. In this study, the regression equation for the dose survival rate was constructed using heavy ion irradiation on rice pollen. Through an immunofluorescence experiment, it was found that DSBs induced by irradiation could be repaired quickly, but the repair of complex damage required more time. RNA-seq of irradiated pollen showed that the gene expression patterns at different time points were significantly different. A total of 5556 differentially expressed genes (DEGs) were screened out, and the number of DEGs decreased with time. DEGs were mainly involved in stress response, protein folding, DNA repair, and other damage response processes at 0-1 h. At 6 h, the cells turned to normal metabolism functions, such as organic synthesis and protein activity. Combined with weighted gene co-expression network analysis (WGCNA) and trend analysis, the key transcription factor OsERF110 was identified in response to heavy ion irradiation, which acts on the nucleus and cell membrane. A total of 45,680 OsERF110 binding peaks were identified by DNA affinity purification sequencing (DAP-seq) in the whole genome. When this method was combined with RNA sequencing (RNA-seq), 62 OsERF110 target genes were further screened. These target genes were involved in DNA repair, stress response, redox, metabolic regulation, and other processes, forming the OsERF110 mediated radiation response regulatory network. The results of this study provide a new target for rice mutation breeding and lay a theoretical foundation for radiation biology research.

Elucidating crops'physiological and molecular mechanisms to adapt to low nitrogen environment and promoting nitrogen transfer from senescent leaves to new leaves is crucial in improving Brassica's nitrogen use efficiency(NUE).Glutamine synthetase gene(GS)plays a vital role in helping plants reassimilate ammonium released from protein degradation in leaves,and it was the focus of our research on this topic.In this study,we identified high(H141)and low(L65)NUE genotypes of Brassica juncea with different responses to low-nitrogen stress.We found that H141 has a lower nitrate content but higher ammonium and free amino acid contents as well as higher nitrate reductase and GS activities in the shoots.These physiological indicators are responsible for the high NUE of H141.Whole-genome resequencing data revealed that 5,880 genes associated with NUE are polymorphic between H141 and L65.These genes participate in various amino acid,carbohydrate,and energy metabolic pathways.Haplotype analysis revealed two haplotypes for BjuB05.GS1.4,Hap1 and Hap2,which have multiple single nucleotide polymorphisms or insertions/deletions in the regulatory regions of the 5'and 3'untranslated regions and introns.Furthermore,the shoot NUE of Hap1 is significantly lower than that of Hap2.These two haplotypes of BjuB05.GS1.4 lead to differences in the shoot NUEs of different genetic populations of mustard and are associated with the local soil nitrogen content,suggesting that they might help mustard to adapt to different geographic localities.In conclusion,the results of our study shed light on the physiological and molecular mechanisms underlying different mustard NUE genotypes and demonstrate the enormous potential of NUE breeding in B.juncea.

Enhancing wheat yield and stress tolerance is a critical long-term objective for global food security. Historically, breeders selected genetic traits from wild wheat relatives for domesticated targets, such as non-shattering and free threshing characteristics, and developed the cultivated wheat. However, the genetic diversity of the cultivated wheat has become narrow after long-term domestication and conscious selection, which seriously limited the yield potential and stress tolerance. Therefore, using wild Triticeae species to broaden the gene pool is an ongoing task for wheat improvement. Psathyrostachy huashanica Keng ex P. C. Kuo (2n = 2x = 14, NsNs), a perennial species of the genus Psathyrostachys Nevski, is restrictively distributed in the Huashan Mountain region of Shaanxi province, China. P. huashanica exhibits considerable potential for wheat breeding due to its valuable agronomic traits such as early maturation, more tillers, abiotic tolerance, and biotic resistance. Over the past four decades, researchers have successfully crossed P. huashanica with common wheat and developed derivative lines with improved agronomic traits. Here, we summarized the morphology, genomic evolution, and derived wheat breeding lines with advanced agronomic characteristics inherited from P. huashanica. This review provides a useful guideline for future research on P. huashanica, and highlights its importance in wheat breeding.

The accumulation of cadmium (Cd) in ryegrass (Lolium multiflorum Lamk.) as a widely used pasture plant poses a serious risk to food safety. This study aimed to investigate the differences in phenotypes, physiology, and expression of metal transporters between four ryegrass genotypes (diploid/tetraploid and Cd-tolerant/sensitive). The diploid/Cd-sensitive genotypes were found to uptake, accumulate, and translocate more Cd compared to the tetraploid/Cd-tolerant genotypes. Cd with more soluble components facilitated the transfer of Cd from root to shoot in the sensitive genotypes. Tetraploid and Cd-tolerant Chuansi No.1 accumulated less Cd in shoots but higher ratio in root cell wall, making it a promising model for studying the mechanisms of plant resistance to Cd stress. The complex regulatory system and dilution effect contributed to the lower uptake and accumulation of Cd in tetraploid genotypes. Moreover, tetraploid genotypes exhibited higher expression of genes that promoted Cd efflux, which could contribute to their lower Cd accumulation. Overall, this study sheds light on the physiological and transcriptional mechanisms of Cd uptake and accumulation by different polyploids, providing guidance for ryegrass breeding and soil improvement.

The plant hormone abscisic acid (ABA) affects ethylene biosynthesis and postharvest shelf life of fruits. However, the family members encoding the ABA core signaling components that are responsible for ABA-induced ethylene biosynthesis and fruit ripening remain unidentified, with the underlying mechanism elusive. Here, we confirm that exogenous ABA treatment induces ethylene biosynthesis and accelerates postharvest banana ripening. Combining transcriptomic analysis and the information of gene families encoding ABA signaling components and downstream transcription factors, we highlight MaPYL3-MaPP2C17-MaSnRK2.3 as one of the major signaling modules responsible for ABA-induced ethylene production. Downstream of the ABA signaling, the transcription factor MabZIP95 is controlled by ABA treatment and directly binds to the promoters of MbACS7, MbACO2, and MbACO3, key for ethylene biosynthesis during banana fruit ripening. The expression of this ABA regulatory module was significantly elevated at 5 days postharvest after ABA treatment, well associated with the earlier and stronger ethylene production. Besides, the comparison of the ABA-related fruit ripening process has been discussed between horticultural crops, suggesting our strategy as effective in the gene discovery towards ABAregulated fruit development. Finally, our work reveals the MaPYL3-MaPP2C17-MaSnRK2.3-MabZIP95MbACS7/MbACO3/MbACO2 regulatory module and indicates its functional involvement in ABA-induced ethylene synthesis and postharvest ripening in banana, providing valuable target genes for the molecular breeding to extend the shelf-life of banana.

Previous studies have demonstrated that γ-Aminobutyric acid (GABA) effectively alleviates heavy metal stresses by maintaining the redox balance and reducing the accumulation of reactive oxygen species (ROS). However, little is known about the role of GABA on programmed cell death (PCD) under Cd treatments in plants. The present study investigated the effects of GABA on Cd-induced PCD in two Brassica species, oilseed rape (Brassica napus, Bn), and black mustard (Brassica juncea, Bj). We observed that GABA significantly alleviated Cd-induced PCD by enhancing antioxidant systems, inhibiting chromatin condensation in the nucleus, and reducing DNA fragmentation under Cd stress. Moreover, GABA may not only reduce caspase-3-like activity by repressing gene expression, but also regulate transcription of PCD-related genes. Bn showed lower Cd accumulation and lower tolerance, with more pronounced PCD, compared with Bj. Our results provide new insights into the mechanism that GABA enhances Cd tolerance in plants.