Photoluminescence (PL) is a crucial property of carbon dots (CDs), which are promising carbon nanomaterials for agricultural applications. Red light signaling positively influences various physiological processes in plant salt tolerance. However, the potential for designing CDs based on light signaling theory to enhance agronomic traits in field crops remains unexplored. In this study, foliar spraying of red-emissive CDs (RCDs) improved salt tolerance in sweetpotato (Ipomoea batatas (L.) Lam) by enhancing nitric oxide (NO)-mediated Na+ homeostasis in roots. A mechanistic investigation attributed this beneficial effect primarily to the PL properties of the RCDs. The expression of genes related to RCD-enhanced Na+ transport in roots was found to be dependent on NO-mediated histone acetylation. For instance, RCDs, including genes encoding the red-light receptor (IbPHYB) and the Na+/H+ antiporter (IbSOS1), triggered comprehensive histone H4 hyperacetylation in salinized sweetpotato roots. IbHY5 was identified as a potential shoot-to-root mobile signal that triggered the hyperproduction of NO in sweetpotato roots under stress conditions. In summary, the RCDs enhanced salt tolerance in sweetpotato via the IbHY5-NO-IbHAM1-IbSOS1 signaling. These findings revealed that the PL properties of CDs could target specific light signaling pathways for field crop improvement.

Purple-fleshed sweet potato (PFSP) (Ipomoea batatas) is a rich source of anthocyanins, which serve as potent antioxidants and contribute to stress tolerance. However, the molecular mechanisms regulating anthocyanin biosynthesis in PFSP under phosphorus stress remain poorly understood. In this study, integrated transcriptomic and metabolomic analyses were conducted using the sweet potato cultivar (Xuzishu No. 8) grown under three phosphorus treatments: XP0 (0 g), XP1 (1.85 g), and XP2 (3.70 g). Although phosphorous did not significantly affect total anthocyanin content, however, marked changes were observed in the activities of key biosynthetic enzymes (CHl, DFR, OPC, PAL and UFGT). RNA-seq analysis identified 8,906 differentially expressed genes (DEGs) with 11,215 novel genes across the treatments. KEGG pathway enrichment analysis revealed that most DEGs were associated phenylpropanoid biosynthesis. Metabolomic profiling detected 110 differentially expressed metabolites (DEMs) among which six were common to all treatments and sixteen metabolites were shared between the treatment groups. Functional annotation of DEMs indicated an overall suppression of anthocyanin biosynthesis pathway, across the treatments, whereas, flavone and flavonol biosynthesis remained consistently active. Notably, Quercetin-3-O-glucoside appeared to play a key role in the restoring anthocyanin biosynthesis. Integrated transcriptome-metabolome analysis showed a strong coordinated regulation between DEGs and DEMs, particularly within anthocyanin and flavonoid biosynthetic pathways. Furthermore, Canonical correspondence analysis (CCA) and principal component analysis (PCA) biplot further revealed that anthocyanin accumulation is controlled by the combined action of multiple genes, with Tai6.6720 identified as a key regulatory gene closely linked with active metabolites (Pelargonidin-3-O- glucoside and cyanidin-3-O- glucoside). Overall, these findings highlight the significant impact of phosphorous stress on transcriptional and metabolic reprogramming of anthocyanin biosynthesis as an adaptive response. This study provides new insights on the regulatory networks that control anthocyanin accumulation in sweet potato and offers a valuable foundation for nutrient management strategies and molecular breeding approaches to improve crop stress tolerance.

Sweetpotato is a typical "potassium(K+)-favoring" crop, and K+ deficiency can lead to slow growth, reduced photosynthetic capacity, and lower yield. Genome-wide association study (GWAS) has been widely used in the identification of plant resistance genes; however, there are limited reports on the discovery of low K+ tolerance genes in sweetpotato. In this study, we conducted a GWAS involving 213 sweetpotato cultivars and identified that IbHSP18.0 was significantly associated with low K+ tolerance. We cloned IbHSP18.0, constructed an overexpression vector, and expressed it in situ in sweetpotato to obtain transgenic seedlings. The experimental results demonstrated that transgenic sweetpotato plants overexpressing IbHSP18.0 exhibited longer shoots, more leaves, higher photosynthesis rates, more abundant roots, as well as higher biomass and K+ accumulation under low K+ stress conditions. These improvements were correlated with elevated activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), along with the effective removal of excess hydrogen peroxide (H2O2) and malondialdehyde (MDA). Additionally, the expression of IbHSP18.0 in sweetpotato induced the expression of K+ channels (IbAKT1-1, IbAKT1-3, and IbKC1-1) and high-affinity K+ transporter IbHAK5 within roots. In conclusion, our findings suggest that IbHSP18.0 plays a crucial role in enhancing the tolerance of sweetpotato to low K+ stress by strengthening the antioxidant defense mechanisms and positively regulating the expression of genes involved in K+ absorption and transport.

Biomass-derived nano carbon dots (CDs) application and sweetpotato (SP) planting can alter soil microbial community structure. However, the impact of these treatments on soil microbial necromass carbon (MNC) and associated mechanisms remains unclear. In this study, we combined pot experiments and laboratory analyses to assess soil physicochemical properties, microbial community characteristics, metabolic enzyme activity and multivariate correlations, aiming to explore the determinants of soil MNC accumulation in Vertisol following CDs application and SP planting. The results showed inconsistent effects of CDs application on soil bacterial and fungal necromass C content. Although CDs application increased bacterial richness and the relative abundances of Proteobacteria, Firmicutes and Cyanobacteria in the absence of SP planting, it failed to enhance bacterial necromass C accumulation. In contrast, CDs application improved soil fungal necromass C content regardless of SP planting. Besides directly increasing soil organic carbon (SOC) concentrations, both CDs application and SP planting enhanced the contributions of fungal necromass C to SOC. However, SP planting neither increased soil dissolved organic carbon (DOC) nor altered the compound contents in DOC solution. Extracellular enzymes related to C-cycling (e.g., (3-alpha-cellobiohydrolase and (3-1,4-xylosidase) also significantly diminished under SP planting without CDs application. Linear discriminant analysis (LDA) identified distinct bacterial and fungal genera between the CDs application and SP planting treatments. Structural equation models (SEMs) revealed that the reduced accumulation of bacterial necromass C was primarily driven by increased (3-1,4-glucosidase activity and shifted in bacterial community composition, which limited microbial substrate utilization and growth. The increased fungal necromass C accumulation was attributed to altering fungal community structure and decreasing alpha-diversity, which promoted necromass formation through sequential assimilation, synthesis, and turnover of CDs and SP carbon inputs. These results highlight the differential responses of bacterial and fungal necromass accumulation to CDs application and SP planting, providing novel insights into the regulatory roles of nano CDs and plant-microbe interactions in SOC sequestration processes in Vertisol.

Plants cope with drought stress by strengthening their survival and growth capabilities through enhancing potassium absorption and utilization. In this study, we evaluate transgenic sweetpotato plants overexpressing potassium transport IbHAK5 responses to drought stresses. Overexpression of IbHAK5 can improve potassium ion (K+) absorption ability under normal condition and drought stress, which may result in the increased drought stress tolerant in transgenic plants. The transgenic plants displayed higher drought stress tolerant than wild-type plants by increasing relative water content (RWC) and alleviating oxidative stress. Transcriptome analysis further identified differentially expressed genes (DEGs) encoding aquaporins and screened K+ channel, peroxidase (POD), glutathione S-transferase (GST), and stress-related genes up-regulated by drought stress, which may provide valuable insights for breeding programs to improve drought stress tolerance. These findings broaden our understanding of the role of IbHAK5 in drought stress resistance, and provide some candidate genes for sweetpotato molecular breeding.

Potassium is a vital element in sweetpotato that plays important roles during its growth and development. In this study, potassium transporter IbHAK5, which is homologous to Arabidopsis HAK5, was cloned and overexpressed in sweetpotato. IbHAK5 encoded a protein of 739 amino acids and localized in the plasma membrane. Two IbHAK5-overexpressing transgenic lines with the highest expression level of IbHAK5 were screened for K+-deficiency stress tolerant assay. Compared with wild type sweetpotato plants, transgenic plants grew well with higher chlorophyll content, and maintain great higher K+ contents via decreasing more K+ effluxes under low potassium ion (− K+) stress condition. Additionally, IbHAK5 can help plants improve root morphology and increase endogenous hormone IAA content under both normal condition and − K+ stress, which may result in the increased root K+ absorption ability. The results indicated that IbHAK5 play an important role in sweetpotato response to − K+ stress, as well as support molecular-assisted breeding with the IbHAK5 gene.

Fertilization are commonly used strategies to alleviate continuous cropping obstacles, but long-term stationary fertilization also causes varying degrees of soil barriers that hinder the growth of crop with the extension of planting years. However, there was currently a lack of systematic research on which soil properties change caused by long-term stationary fertilization were the reasons for the production obstacles in sweetpotatoplanting fields. Here, soil samples from a 21-year-old continuously sweetpotato-planting field covering four fertilizations (CK: no fertilizer; M: organic manure only; NPK: chemical fertilizer only; MNPK: chemical fertilizer plus organic manure) were collected and analyzed. Compared with CK, fertilization significantly increased soil microbial biomass carbon content, the activities of urease, invertase and alkaline phosphatase, and the increase amplitudes in these indicators was the largest in MNPK. Moreover, fertilization significantly decreased the relative abundance of harmful fungi (i.e., Gibberella_avenacea, , Alternaria_alternata, , Mortierella_alpina, , etc.) compared with CK. Especially, the relative abundance of fungal pathogens, Fusarium_oxysporum and Fusarium_proliferatum, , showed a trend of MNPK

The use of nitrogen (N) fertilizers increases crop yield, but the accumulation of residual N in agricultural soils poses significant environmental risks. Improving the N use efficiency (NUE) of crops can help reduce N pollution. While nanomaterials have been shown to enhance crop agronomic traits, more research is needed to clarify the regulatory mechanisms involved. In this study, foliar spraying of carbon dots (CDs, 1 mg mL-1) derived from Salvia miltiorrhiza increased the activity of plasma membrane H+-ATPase in Arabidopsis thaliana roots, promoting the uptake, transport, and assimilation of NO3-and NH4+. The upregulation of N metabolism-related genes, such as AtAMTs and AtNRTs, was also observed in A. thaliana roots. Transcriptome analysis suggested that this regulatory effect is mediated by the shoot-to-root mobile polypeptide CEPD1 (C-terminally encoded peptide DOWNSTREAM 1) signaling pathway. Additionally, foliar application of CDs increased the NUE of sweetpotato ( Ipomoea batatas (L.) Lam.) from 2.5% to 8.1%. The upregulation of genes such as CEPD1 in leaves was observed following CDs application under different N conditions. Finally, foliar spraying of CDs significantly increased field yield and enhanced tolerance to low N stress in sweetpotato. Overall, this study demonstrated that foliar application of CDs improved NUE in plants through CEPD1-dependent signaling.

Plant roots are sensitive to potassium (K+) deficiency signals. Therefore, regulating root growth by exogenous methods is a vital strategy to improve low K+ tolerance of sweetpotato. We studied the effects of exogenous indole-3-acetic acid (IAA) on growth, K+ absorption, and root characteristics in sweetpotato exposed to low K+ treatment (LK). LK significantly inhibited dry mass, K+ concentration and accumulation, as well as the root elongation (length) and branching (forks and crossings) in sweetpotato seedlings. However, exogenous IAA increased the length, ratio, and density of lateral roots and promoted absorption and accumulation of K+, which effectively alleviated the inhibitory effect of low K+. Exogenous IAA also increased the expression levels of auxin synthesis (IbYUC6 and IbTAR2) and transport (IbPIN1, IbPIN3, and IbPIN8) genes in leaves and roots, which promoted the increase of endogenous IAA content. Furthermore, exogenous IAA was more effective on low-K-tolerant variety (XS32) than low-K-sensitive variety (NZ1) under LK stress, depending on their different IAA synthesis and transport strategies. These results indicated that exogenous IAA enhanced root responsiveness of sweetpotato to low K+ stress by modulating auxin biosynthesis and transport, thereby improving the tolerance of sweetpotato to low K+ stress.

Improving the utilization efficiency of sweetpotato on soil legacy phosphorus (P) is not only a need for sustainable utilization of P resources, but also an urgent need for cost saving and efficiency enhancement in the sweetpotato industry. Nano carbon dots (CDs), as an exogenous regulatory measure, were sprayed (10 mL, 1.5 mg mL− 1) on sweetpotato seedlings (Shangshu 19 and Xushu 32) grown in low P stress (spraying ultra-pure water as control), after which the root morphological, physiological parameters and rhizosphere properties were analyzed. Foliar-applied CDs promoted the root growth (e.g., increasing root length, projected area, surface area, etc.), and increased the expression of root phosphate transport genes (PHO1, PHT1-4). Meanwhile, foliar-applied CDs significantly reduced the expression level of inositol phosphate of root, and improved phoD gene abundance in Shangshu 19 rhizosphere. For Xushu 32, the expression level of roots citric acid and oxalic acid, and the abundance of rhizosphere pqqC gene increased after spaying CDs. Principal coordinates analysis (PCoA) showed that phoD-harboring Tuwongella, Prosthecobacter, Leptolyngbya, Rubinisphaera, and pqqC-harboring Nitrincola, Novimethylophilus, Ramlibacter, Mycobacterium, Thiomonas played key roles on the solubilization of insoluble P in Shangshu 19 and Xushu 32 rhizosphere, respectively. These alterations could increase available P content in Shangshu 19 (53

Potassium is a vital element in sweetpotato that plays important roles during its growth and development. In this study, potassium transporter IbHAK5, which is homologous to Arabidopsis HAK5, was cloned and overexpressed in sweetpotato. IbHAK5 encodes a protein of 739 amino acids and localized in the plasma membrane. Two IbHAK5-overexpressing transgenic (HO) lines with the highest expression level of IbHAK5 were screened for K+-deficiency stress tolerant assay. Compared with wide type (WT) sweetpotato plants, transgenic plants grew well with higher chlorophyll content, and maintain great higher K+ contents via decreasing more K+ effluxes under low potassium ion (− K+) stress condition. Additionally, IbHAK5 can help plants improve root morphology and increase endogenous hormone IAA content under both normal condition and − K+ stress, which may result in the increased root K + absorption ability. The results indicated that IbHAK5 play an important role in sweetpotato response to – K+ stress, as well as support molecular-assisted breeding with the IbHAK5 gene.

Background Sweetpotato is a typical ‘‘potassium (K + ) favoring’’ food crop, which root differentiation process needs a large supply of potassium fertilizer and determine the final root yield. To further understand the regulatory network of the response to low potassium stress, here we analyze physiological and biochemical characteristics, and investigated root transcriptional changes in two sweetpotato genotypes, namely, - K tolerant “Xu32” and - K susceptible“NZ1”. Result We found Xu32 had the higher capability of K + absorption than NZ1 with better growth performance, higher net photosynthetic rate and higher chlorophyll contents under low potassium stress, and identified 889 differentially expressed genes (DEGs) in Xu32, 634 DEGs in NZ1, 256 common DEGs in both Xu32 and NZ1. The Gene Ontology (GO) term in molecular function enrichment analysis revealed that the DEGs under low K + stress are predominately involved in catalytic activity, binding, transporter activity and antioxidant activity. Moreover, the more numbers of identified DEGs in Xu32 than that in NZ1 responded to K + -deficiency belong to the process of photosynthesis, carbohydrate metabolism, ion transport, hormone signaling, stress-related and antioxidant system may result in different ability to K + -deficiency tolerance. The unique genes in Xu32 may make a great contribution to enhance low K + tolerance, and provide useful information for the molecular regulation mechanism of K + -deficiency tolerance in sweetpotato. Conclusions The common and distinct expression pattern between the two sweetpotato genotypes illuminate a complex mechanism response to low potassium exist in sweetpotato. The study provides some candidate genes, which can be used in sweetpotato breeding program for improving low potassium stress tolerance.

Soil microbial communities and extracellular enzymes are pivotal in governing the dynamics of soil carbon (C) and phosphorus (P) cycling. Nevertheless, comprehending the underlying regulatory factors and intricate in-teractions among these vital indicators remains an inadequately explored aspect, especially within the scenario of long-term fertilization. Long-term fertilization experiments were conducted on calcareous alluvial soil. The five fertilization regimes selected were as follows: without fertilization treatment (CK); inorganic NK fertilization treatment (NK); inorganic NPK fertilization treatment (NPK); organic fertilization treatment (M); and combined inorganic NPK with organic fertilization treatment (NPKM). The soil physicochemical properties, beta-glucosidase (BG), and alkaline phosphomonoesterase (ALP) activities were determined, together with microbial (bacterial and fungal) community DNA sequences and subsequent bioinformatics analysis after 38 years of different fertilization. The results showed that the content of soil organic carbon (SOC) and available P and the activities of BG and ALP were the highest after M and NPKM treatments, which were 79-104 %, 26-36 times, 161-171 %, and 75-91 % higher than CK, respectively. Hierarchical clustering analysis showed that the bacterial and fungal community structures in M and NPKM treatments were similar, but the community structures in non-organic fertilization treatments (CK, NK, and NPK) were significantly different from those in organic fertilization treatments. The indicator species and correlation analysis combined revealed that most indicator species in organic fertilizer treatments were significantly positively correlated with soil BG and ALP, while most indicator species in non-organic fertilizer (CK and NK) treatments were significantly negatively correlated with soil BG and ALP. Organic fertilization treatments favored the growth of the bacterial genus Lysobacter and the fungal genera Acremonium and Mortierella and were significantly positively correlated with BG and ALP activities. Redundancy analysis revealed that SOC is the most important factor in shaping microbial community structure. Co-occurrence network analysis showed organic fertilization had higher network complexity, more keystone taxa, and more associations among microbial taxa compared with non-organic fertilization (CK + NK). Structural equation models revealed that microbial community structure is the direct driving factor of BG and ALP activities and their interactions, and SOC modulated the relationship between microbial community structure and BG and ALP activities. This study highlights how the application of organic fertilizer enhanced the C-and P-cycling enzyme activities, reshaped the soil microbial communities, and regulated these crucial indicators and their interactions by SOC.

以63份不同基因型甘薯品种(系)为材料,采用水培试验,设置低磷胁迫(0.01 mmol·L-1 KH2PO4)和正常施磷(1 mmol·L-1 KH2 PO4)处理,调查并比较不同磷水平下63个品种(系)甘薯苗期地上部干质量(mS)、根干质量(mR)、总干物质增加量(Δm)、蔓长(lV)、根长(lR)、根冠比(R)、地上部磷素积累量(mSP)、根系磷素积累量(mRP)、地上部磷含量(wSP)、地上部磷变化量(ΔwSP)、根磷含量(wRP)、磷素生理利用效率(E)12个性状表征值的差异.通过相关性分析、因子分析、模糊隶属函数法以及聚类分析法对不同甘薯品种进行耐低磷性评价和基因型差异分类.结果表明:低磷胁迫下,不同甘薯材料苗期各性状均受到不同程度的影响;mR、mRP、mSP、wSP和ΔwSP可作为鉴定耐低磷甘薯基因型的苗期筛选指标.以耐低磷性综合评价值(D)进行聚类分析,将供试甘薯材料划分为耐低磷基因型、中度耐低磷基因型、低度耐低磷基因型和不耐低磷基因型,筛选出徐薯34、红优、坦桑尼亚和苏薯8号4个耐低磷基因型甘薯.供磷水平显著影响甘薯苗期各性状指标,基于甘薯种质间农艺性状、磷素积累量和磷素生理利用效率的差异,结合4种分析方法,可以准确评价甘薯种质资源苗期磷效率状况,为甘薯耐低磷生理机制研究和磷高效品种的选育提供理论依据.

Plants can adapt to the spatial heterogeneity of soil nutrients by changing the morphology and architecture of the root system. Here, we explored the role of auxin in the response of sweetpotato roots to potassium (K+) deficiency stress. Two sweetpotato cultivars, Xushu 32 (low-K-tolerant) and Ningzishu 1 (low-K-sensitive), were cultured in low K+ (0.1 mmol L−1, LK) and normal K+ (10 mmol L−1, CK) nutrient solutions. Compared with CK, LK reduced the dry mass, K+ content, and K+ accumulation in the two cultivars, but the losses of Xushu 32 were smaller than those of Ningzishu 1. LK also affected root growth, mainly impairing the length, surface area, forks number, and crossings number. However, Xushu 32 had significantly higher lateral root length, density, and surface area than Ningzishu 1, closely related to the roots’ higher indole-3-acetic acid (IAA) content. According to the qPCR results, Xushu 32 synthesized more IAA (via IbYUC8 and IbTAR2) in leaves but transported and accumulated in roots through polar transport (via IbPIN1, IbPIN3, and IbAUX1). It was also associated with the upregulation of auxin signaling pathway genes (IbIAA4 and IbIAA8) in roots. These results imply that IAA participates in the formation of lateral roots and the change in root architecture during the tolerance to low K+ stress of sweetpotato, thus improving the absorption of K+ and the formation of biomass.

[目的]真菌在根际土壤养分循环中发挥重要作用,探究磷肥施用方法对甘薯根际土壤真菌群落的影响,以减少施肥可能对甘薯根际土壤微生态环境的不利影响.[方法]甘薯-小麦轮作长期肥料定位试验位于江苏南京,始于 2011 年.2020 年选择该定位试验中的 3 个处理:不施磷肥(NK)、单施化肥(NPK)和有机无机肥配合(NPKM),在甘薯膨大期采集储藏根与纤维根根际土壤,测定化学性质,并利用Illumina Novaseq高通量测序技术,分析真菌群落相对丰度、群落组成与多样性,及其与根际土壤化学性质的关系.[结果]1)施肥处理改变了两类根根际土壤化学性质,储藏根和纤维根的根际土壤有机碳、溶解性有机碳、速效钾含量均表现为NPKM>NPK>NK处理,有效磷(AP)含量表现为NPK>NPKM>NK(P<0.05),同一处理两类根际间只有有效磷含量差异显著;纤维根和储藏根的根际土壤pH均以NPKM处理最高,NPK处理最低且显著低于NK处理,NPKM处理的纤维根根际pH显著高于储藏根根际 0.81 个单位.2)3 个施肥处理两类根系根际土壤的优势真菌类群均为子囊菌门(Ascomycota,70.2％～77.9％)、担子菌门(Basidiomycota,5.9％～8.5％)和被孢霉门(Mortierellomycota,1.8％～8.1％).3 个处理间储藏根根际土壤子囊菌门的相对丰度无显著差异,而NK处理纤维根根际土壤子囊菌门的相对丰度显著高于NPKM处理(P<0.05);担子菌门和被孢霉门的相对丰度在NPK和NPKM处理间以及两类根系的根际土壤间均无显著差异,而NK处理的储藏根根际土壤担子菌门和被孢霉门的相对丰度较NPK处理分别低 70.4％和 62.9％,较NPKM处理分别降低 44.0％和 151％(P<0.05).3)NPKM和NPK处理储藏根根际特有的真菌OTUs数分别为 122 和 113 个,而NK处理为 86 个,远低于NPKM和NPK处理.NPKM处理纤维根根际特有的真菌OTUs数最高(160 个),而NPK和NK处理分别为 114 和 127 个.NK处理的纤维根根际土壤观察到的物种数和Shannon多样性指数显著高于储藏根(P<0.05),NPKM处理两类根际的观察到的物种数和Shannon指数在 3 个处理中最高.拓扑网络分析表明,储藏根根际土壤真菌类群关系较纤维根根际的更为复杂,而纤维根根际土壤真菌群落具有更强的相互作用关系.冗余分析(RDA)结果表明,根际土壤有效磷、有机碳含量和pH与根际土壤真菌群落结构显著相关(P<0.05).[结论]长期施用磷肥降低了甘薯两类根际土壤的pH,但显著提高了有机碳、有效磷和速效钾含量,磷肥配施有机肥还避免了pH的降低,因而较单施化肥更有效地提高了根际土壤的真菌数量和多样性.

依托40年长期定位试验研究平台,采用13CO2脉冲标记方法对4种不同施肥方式下光合碳在甘薯-土壤系统中的分配进行了定量研究.结果表明:施肥能显著增加甘薯植株各器官的生物量与干物质量,以有机无机配施处理增加幅度最为显著.甘薯-土壤系统光合固定碳转移较快,且分配差异较大,其13C丰度在脉冲标记1 d后表现为:叶片、叶柄＞藤蔓、块根＞土体,且不施肥处理地上部13C丰度显著高于施肥处理.脉冲标记30 d后,甘薯植株各器官13C丰度降低,其中在地上部分配比例为19.38％～31.44％,块根中为60.19％～71.86％,而土体13C丰度却略有升高,分配比例为8.05％～11.11％;与不施肥处理相比,施肥处理显著增加块根中13C含量,且MNPK处理块根中13C含量显著高于NPK和M处理,表明在甘薯膨大期施肥处理有利于光合碳在块根中累积,其中以有机无机配施累积效果更为显著.

The pqqC and phoD genes encode pyrroloquinoline quinone synthase and alkaline phosphomonoesterase (ALP), respectively. These genes play a crucial role in regulating the solubilization of inorganic phosphorus (Pi) and the mineralization of organic phosphorus (Po), making them valuable markers for P-mobilizing bacterial. However, there is limited understanding of how the interplay between soil P-mobilizing bacterial communities and abiotic factors influences P transformation and availability in the context of long-term fertilization scenarios. We used real-time polymerase chain reaction and high-throughput sequencing to explore the characteristics of soil P-mobilizing bacterial communities and their relationships with key physicochemical properties and P fractions under long-term fertilization scenarios. In a 38-year fertilization experiment, six fertilization treatments were selected. These treatments were sorted into three groups: the non-P-amended group, including no fertilization and mineral NK fertilizer; the sole mineral-P-amended group, including mineral NP and NPK fertilizer; and the organically amended group, including sole organic fertilizer and organic fertilizer plus mineral NPK fertilizer. The organically amended group significantly increased soil labile P (Ca2-P and enzyme-P) and Olsen-P content and proportion but decreased non-labile P (Ca10-P) proportion compared with the sole mineral-P-amended group, indicating enhanced P availability in the soil. Meanwhile, the organically amended group significantly increased soil ALP activity and pqqC and phoD gene abundances, indicating that organic fertilization promotes the activity and abundance of microorganisms involved in P mobilization processes. Interestingly, the organically amended group dramatically reshaped the community structure of P-mobilizing bacteria and increased the relative abundance of Acidiphilium, Panacagrimonas, Hansschlegelia, and Beijerinckia. These changes had a greater positive impact on ALP activity, labile P, and Olsen-P content compared to the abundance of P-mobilizing genes alone, indicating their importance in driving P mobilization processes. Structural equation modeling indicated that soil organic carbon and Po modulated the relationship between P-mobilizing bacterial communities and labile P and Olsen-P, highlighting the influence of SOC and Po on the functioning of P-mobilizing bacteria and their impact on P availability. Overall, our study demonstrates that organic fertilization has the potential to reshape the structure of P-mobilizing bacterial communities, leading to increased P mobilization and availability in the soil. These findings contribute to our understanding of the mechanisms underlying P cycling in agricultural systems and provide valuable insights for enhancing microbial P mobilization through organic fertilization.

【Objective】The objective of this paper was to analyze the genetic mechanisms of nitrogen use efficiency (NUE), and to explore the loci and candidate genes associated nitrogen (N) efficient traits, to provide support for the N-efficient molecular breeding and genetic improvement of sweetpotato.【Method】A total of 129 sweetpotato cultivars from all over the world were treated with N deficiency (0 mmol·L-1) and normal N (14 mmol·L-1). A hydroponic experiment was conducted to facilitate the genome-wide association study (GWAS) of six phenotypic traits (shoot biomass increment, root biomass increment, shoot N accumulation, root N accumulation, shoot N physiological utilization efficiency, and root N physiological utilization efficiency) of sweetpotato at the seedling stage. The N-efficient candidate genes were identified based on the GWAS and subsequently- verified using RT-qPCR.【Result】There were wide variations among the six traits related to NUE in sweetpotato under the normal N and N deficiency treatment conditions. The coefficient of variation (CV) of the shoot biomass increment under the N deficiency treatment condition was the greatest at 69.5%. The CV of the root N physiological utilization efficiency under N deficiency treatment condition was the smallest at 12.1%. All five traits were significantly correlated except for root N physiological utilization efficiency. The MLM model was used to conduct a GWAS of the six phenotypic trait values. A total of 134 QTL and 888 SNP loci were identified as being significantly associated with four out of the six traits, namely, shoot biomass increment, root biomass increment, root N accumulation, and shoot N physiological utilization efficiency. A total of 93 SNP markers across ten regions were significantly associated with shoot N physiological utilization efficiency with a high reliability. Six N efficiency candidate genes were obtained via gene annotation. RT-qPCR verified that the three candidate genes (itf01g08120.t1, itf01g22030.t1 and itf01g221000.t2) encoded glutamate dehydrogenase, NPH3 protein and TIP41-like protein, respectively, which warrants further research.【Conclusion】A total of 888 SNP loci associated with N utilization traits were detected in 129 sweetpotato cultivars. Among these, 93 SNP loci were significantly associated with shoot N physiological utilization efficiency, and six candidate genes were identified. Preliminary verification indicated that the itf01g08120.t1, itf01G2203.t1 and itf01g22100.t2 genes hold promising value for further research.