AhRt3, which governs the red testa of peanut, was narrowed down to a 125.30 kb region, and one gene encoding anthocyanin reductase was identified as the putative candidate gene. Testa color is a special characteristic of peanuts (Arachis hypogaea L.), and those with dark testa have been focused on recent years owing to their high-anthocyanin content and increased antioxidant nutritional value. However, the genetic mechanisms underlying this trait remain limited. To identify the gene responsible for the red testa color in peanuts, an F2 population was constructed by crossing YH91 (pink testa) with JHT1 (red testa). Genetic analysis revealed that the red testa was controlled by a single dominant gene named AhRt3 (Arachis hypogaea Red Testa 3). Through bulked segregant analysis sequencing, AhRt3 was preliminarily mapped to the chromosome Arahy.03 and subsequently narrowed to a 125.30 kb genomic region containing 12 potential candidate genes. RNA-seq analysis revealed that 4,880 genes were differentially expressed in the seed testa, with only the candidate gene Arahy.W8TDEC exhibiting higher expression levels in JHT1 than in YH91. Additionally, sequence variation, functional annotation, and expression profiling confirmed that Arahy.W8TDEC, which encodes an anthocyanin reductase, may be a candidate gene for AhRt3. The structural variation involving an inversion between the sixth exon and the 3’UTR of Arahy.W8TDEC resulted in altered amino acids closely associated with the red testa phenotype in peanuts. In conclusion, this study highlights the role of a novel gene in regulating red testa and contributes valuable insights into the genetic basis of seed testa in peanuts.

Peanut (Arachis hypogaea L.) is an important oilseed crop worldwide. However, soil salinization becomes one of the main limiting factors of peanut production. Therefore, developing salt-tolerant varieties and understanding the molecular mechanisms of salt tolerance is important to protect peanut yield in saline areas. In this study, we selected four peanut varieties with contrasting response to salt challenges with T1 and T2 being tolerance and S1 and S2 being susceptible. High-throughput RNA sequencing resulted in more than 314.63 Gb of clean data from 48 samples. We identified 12,057 new genes, 7,971of which have functional annotations. KEGG pathway enrichment analysis of uniquely expressed genes in salt-tolerant peanut revealed that upregulated genes in the root are involved in the MAPK signaling pathway, fatty acid degradation, glycolysis/gluconeogenesis, and upregulated genes in the shoot were involved in plant hormone signal transduction and the MAPK signaling pathway. Na+ content, K+ content, K+/ Na+, and dry mass were measured in root and shoot tissues, and two gene co-expression networks were constructed based on weighted gene co-expression network analysis (WGCNA) in root and shoot. In this study, four key modules that are highly related to peanut salt tolerance in root and shoot were identified, plant hormone signal transduction, phenylpropanoid biosynthesis, starch and sucrose metabolism, flavonoid biosynthesis, carbon metabolism were identified as the key biological processes and metabolic pathways for improving peanut salt tolerance. The hub genes include genes encoding ion transport (such as HAK8, CNGCs, NHX, NCL1) protein, aquaporin protein, CIPK11 (CBL-interacting serine/threonine-protein kinase 11), LEA5 (late embryogenesis abundant protein), POD3 (peroxidase 3), transcription factor, and MAPKKK3. There were some new salt-tolerant genes identified in peanut, including cytochrome P450, vinorine synthase, sugar transport protein 13, NPF 4.5, IAA14, zinc finger CCCH domain-containing protein 62, beta-amylase, fatty acyl-CoA reductase 3, MLO-like protein 6, G-type lectin S-receptor-like serine/threonine-protein kinase, and kinesin-like protein KIN-7B. The identification of key modules, biological pathways, and hub genes in this study enhances our understanding of the molecular mechanisms underlying salt tolerance in peanuts. This knowledge lays a theoretical foundation for improving and innovating salt-tolerant peanut germplasm.

Vitamin C plays an important role in plant antioxidation, photosynthesis, growth and development, and metabolism. In this study, a gene AhPMM, which is involved in vitamin C synthesis and responds significantly to low temperature, NaCl, polyethylene glycol (PEG) and abscisic acid (ABA) treatments, was cloned from peanut. An AhPMM overexpression vector was constructed, and transferred to a peanut variety Junanxiaohong using the pollen tube injection method. PCR test on the T3 generation transgenic peanut plants showed a transgenics positive rate of 42.3%. HPLC was used to determine the content of reducing vitamin C (AsA) and total vitamin C in the leaves of transgenic plants. The results showed that the content of AsA in some lines increased significantly, up to 1.90 times higher than that of the control, and the total vitamin content increased by up to 1.63 times compared to that of the control. NaCl and ABA tolerance tests were carried out on transgenic seeds. The results showed that the salt tolerance of transgenic seeds was significantly enhanced and the sensitivity to ABA was weakened compared to that of the non-transgenic control. Moreover, the salt tolerance of the transgenic plants was also significantly enhanced compared to that of the non-transgenic control. The above results showed that AhPMM gene not only increased the vitamin C content of peanut, but also increased the salt tolerance of transgenic peanut seeds and plants. This study may provide a genetic source for the molecular breeding of peanut for enhanced salt tolerance.

Ethylene plays essential roles in plant growth, development and stress responses. The ethylene signaling pathway and molecular mechanism have been studied extensively in Arabidopsis and rice but limited in peanuts. Here, we established a sand-culture method to screen pingyangmycin mutagenized peanut lines based on their specific response to ethylene (“triple response“). An ethylene-insensitive mutant, inhibition of peanut hypocotyl elongation 1 (iph1), was identified that showed reduced sensitivity to ethylene in both hypocotyl elongation and root growth. Through bulked segregant analysis sequencing, a major gene related to iph1, named AhIPH1, was preliminarily mapped at the chromosome Arahy.01, and further narrowed to a 450-kb genomic region through substitution mapping strategy. A total of 7014 genes were differentially expressed among the ACC treatment through RNA-seq analysis, of which only the Arahy.5BLU0Q gene in the candidate mapping interval was differentially expressed between WT and mutant iph1. Integrating sequence variations, functional annotation and transcriptome analysis revealed that a predicated gene, Arahy.5BLU0Q, encoding SNF1 protein kinase, may be the candidate gene for AhIPH1. This gene contained two single-nucleotide polymorphisms at promoter region and was more highly expressed in iph1 than WT. Our findings reveal a novel ethylene-responsive gene, which provides a theoretical foundation and new genetic resources for the mechanism of ethylene signaling in peanuts

The K+ transporter KT/HAK/KUP (K+ transporter/high-affinity K+/K+ uptake) family has a critical effect on K+ uptake and translocation in plants under different environmental conditions. However, the functional analysis of KT/HAK/KUP members in sweet potatoes is still limited. The present work reported the physiological activity of a new gene, IbHAK11, in the KT/HAK/KUP family in sweet potatoes. IbHAK11 expression increased significantly in the low K+-tolerant line compared with the low K+-sensitive line following treatment with low K+ concentrations. IbHAK11 upregulation promoted root growth in Arabidopsis under low K+ conditions. Under high saline stress, transgenic lines had superior growth and photosynthetic characteristics compared with the wild-type (WT). As for IbHAK11-overexpressing plants, activation of both the non-enzymatic and enzymatic reactive oxygen species (ROS) scavenging systems was observed. Therefore, IbHAK11-overexpressing plants had lower malondialdehyde (MDA) and ROS levels (including H2O2 and O2−) compared with WT under salt-induced stress. We also found that under both low K+ and high salinity conditions, overexpression of IbHAK11 enhanced K+ translocation from the root to the shoot and decreased Na+ absorption in Arabidopsis. Consequently, IbHAK11 positively regulated K+ deficiency and high salinity stresses by regulating K+ translocation and Na+ uptake, thus maintaining K+/Na+ homeostasis in plants.

有性杂交是花生(Arachis hypogaea L.)育种的重要途径,真杂种鉴定对于遗传群体的构建以及新品种选育至关重要.花生含油量的表型鉴定极易受到环境条件的影响,且目前缺少可用的分子标记.本研究选用高油及普通油酸亲本宇花14号与低油及高油酸亲本LOP215杂交构建含油量相关遗传群体.宇花14号含有AhFAD2A及AhFAD2B位点,基因型为AABB,LOP215含有AhFAD2a及AhFAD2b位点,基因型为aabb.以宇花14号为母本、LOP215为父本杂交,收获F1杂交籽仁,采用竞争性等位基因特异性PCR(Kompetitive Allele Specific PCR,KASP)检测AhFAD2基因型,剔除AhFAD2基因型为纯合的籽仁,选留FAD2基因型为杂合的F1真杂种.F1真杂种单粒播种收获后,单株检测含油量,对于F2表型无明显分离的株系,取各单株叶片等量混合后提取DNA,进行AhFAD2基因型检测再次确认AhFAD2位点的杂合性.经二次验证后的F2籽粒经连续自交6代后选育出包含460个家系的重组自交系(recombinant inbred lines,RIL)群体,其含油量呈连续正态分布,可作为含油量基因定位的有效分离群体.本试验以AhFAD2作为选择标记能简单高效地筛选出真杂种,构建目标性状分离群体,为花生含油量基因定位及高低油花生品种选育提供材料.

项目针对当前缺乏耐盐抗旱花生新品种、科技成果推广体制活力弱、人才培训形式单一等问题,发明耐盐抗旱花生选育新技术培育新品种、激活成果转移转化活力、构建"云上+线下"双维度成果推广体系,探索出一条"发展耐盐抗旱花生产业、培育新型农民、建设美丽农村"的可行路径和"可复制、能推广"的耐盐抗旱花生产业发展新模式,对提高现代农业科技成果的转移转化和推广起到了积极作用,取得巨大的经济和社会效益.

Drought is the main factor restricting peanut growth, but the molecular mechanism underlying peanut drought tolerance remains unclear. Herein, the seedling stage of drought-resistant peanut cultivar J11 was subjected to drought stress, and its proteomic profile was systematically analysed by isobaric tags for relative and absolute quantification (iTRAQ), the results of which were further complemented with our previous transcriptome results. A total of 4,018 proteins were identified by proteomic analysis, which revealed that the expression levels of 69 proteins were altered under drought stress. Among the differentially expressed proteins (DEPs), 50 were upregulated, and 19 were downregulated. The most enriched metabolic pathways for these DEPs were those involving phenylpropanoid biosynthesis, flavonoid biosynthesis, and plant hormone signal transduction. The proteomic data and previous transcriptome results revealed 44 groups of genes/proteins with the same expression trend, including a LEA (Late embryogenesis abundant) gene, AhLEA2. Our present study showed that overexpression of the AhLEA2 gene enhanced the drought resistance of transgenic Arabidopsis plants, and the activities of related antioxidant enzymes in the transgenic plants significantly changed. The AhLEA2 gene was found to be located in the cytoplasm and cell membrane by subcellular localization experiments. This work systematically analysed the differentially expressed proteins in peanut in response to drought stress, providing important candidates for further functional analysis of the stress response of peanut. Our results also indicated that AhLEA2 plays an important role in the peanut response to drought stress.

当前,提高我国食用油自给率是一项重要任务.对花生品种选育、推广现状进行梳理,分析存在的问题及原因,提出下一步的措施建议.以期凝聚花生种业力量,从品种端发力,全力推进花生提产能行动,为花生扩种、提质、增效提供高质量的种源.

To study the molecular mechanism of salt stress response of peanut small GTP binding protein gene AhRabG3f, a 1 914 bp promoter fragment upstream of the start codon of AhRabG3f gene (3f-P) from peanut was cloned. Subsequently, five truncated fragments (3f-P1-3f-P5) with lengths of 1 729, 1 379, 666, 510 and 179 bp were obtained through deletion at the 5' end, respectively. Plant expression vectors where these six promoter fragments were fused with the gus gene were constructed and transformed into tobacco by Agrobacterium-mediated method, respectively. GUS expression in transgenic tobacco and activity analysis were conducted. The gus gene expression can be detected in the transgenic tobacco harboring each promoter segment, among which the driving activity of the full-length promoter 3f-P was the weakest, while the driving activity of the promoter segment 3f-P3 was the strongest. Upon exposure of the transgenic tobacco to salt stress, the GUS activity driven by 3f-P, 3f-P1, 3f-P2 and 3f-P3 was 3.3, 1.2, 1.9 and 1.2 times compared to that of the transgenic plants without salt treatment. This suggests that the AhRabG3f promoter was salt-inducible and there might be positive regulatory elements between 3f-P and 3f-P3 in response to salt stress. The results of GUS activity driven by promoter fragments after salt treatment showed that elements included MYB and GT1 between 1 930 bp and 1 745 bp. Moreover, a TC-rich repeat between 682 bp and 526 bp might be positive cis-elements responsible for salt stress, and an MYC element between 1 395 bp and 682 bp might be a negative cis-element responsible for salt stress. This study may facilitate using the induced promoter to regulate the salt resistance of peanut.

Additional file 18: Supplementary table 8.

为加强黄河三角洲盐碱地的开发利用,扩大花生种植面积,提高花生产量,本研究以17份花生品种(系)为材料,利用水培方法,测定不同盐浓度下萌发期发芽率.确定0.7％NaCl浓度作为花生品种萌发期耐盐性鉴定的最适浓度,共筛选出5个耐盐品种(系).在山东平度非盐碱地和东营盐碱地分别种植5个耐盐和4个非耐盐品种(系),测定产量性状相关指标.结果表明,盐碱胁迫显著降低花生发芽率,明显抑制花生的生长发育和产量.高油酸品种宇花18号表现出较强的耐盐碱性,其次是化学诱变突变体品系ST24-1、ST24-8和ST24-11,均适于盐碱地种植,为耐盐碱花生品种的选育提供了新材料.本研究表明,萌发期耐盐性的鉴定可作为花生耐盐碱鉴定的基础指标之一.

Peanut ( Arachis hypogaea L.) is an important crop used for oil production, and oleic acid is a major factor in determining oil quality. Alterations in the oleic acid content can improve the nutritional quality and oxidative stability and prolong the shelf life of peanut products. The objective of this study was to develop a peanut variety with a high-oleic-acid content and high yield. One elite variety, “huayu22,” was hybridized with the high-oleic-acid “KN176” donor and backcrossed for four generations as the recurrent parent using fad2 marker-assisted backcross selection. Based on the Kompetitive allele-specific PCR (KASP) screening of fad2 markers, the oleic acid content of advanced generations derived by selfing was assessed by near-infrared reflectance spectroscopy and gas chromatography. The genetic background recovery rate of four BC 4 F 4 lines showed an average of 92.34% and was confirmed by genotyping using the Axiom_ Arachis 58 K SNP array. Across these superior lines in BC 4 F 6 generations, one line with a high-oleic-acid content and high yield was detected and named “YH61.” In particular, yield comparison experiments showed that YH61 exhibited high and stable yield at three different locations and was moderately resistant to leaf spot disease. The distinctness, uniformity and stability (DUS) testing for two consecutive years suggested that YH61 reached the standard for variety rights application. The use of the peanut variety YH61 contributed to the expansion of the cultivation area due to its high value in the oleic acid market and the proven economic benefits in China. This study demonstrated that the marker-assisted backcross strategy based on a cost-effective KASP assay and SNP array for the detection of mutations in fad2 and genetic background evaluation can be used to create efficient peanut breeding programs and contribute to oil quality and high-yield stability.

Auxin response factors (ARFs) are transcription factors that regulate the transcription of auxin-responsive genes during plant growth and development. In this study, 29 and 30 ARF members were identified from the two wild peanut species, A. duranensis and A. ipaensis, respectively. The ARFs, including their classifications, conserved domains and evolutionary relationships were characterized. RNA-seq analyses revealed that some of the ARF genes were responsive to abiotic stress, particularly high salinity. In addition to abiotic stress, the expression of 2 ARF members was also regulated by biotic stress, specifically Bradyrhizobium infection in A. duranensis. The ARF gene Arahy.7DXUOK was predicted to be a potential target of miR160. Overexpression of miR160 could cause degradation of the Arahy.7DXUOK target gene transcript and increased salt tolerance in miR160OX transgenic plants. Therefore, these molecular characterization and expression profile analyses provide comprehensive information on ARF family members and will help to elucidate their functions to facilitate further research on peanuts.

Background The cultivated peanut ( Arachis hypogaea L., AABB) is an allotetraploid hybrid between two diploid peanuts, A. duranensis (AA genome) and A. ipaensis (BB genome). Miniature inverted-repeat transposable elements (MITEs), some of which are known as active nonautonomous DNA transposons with high copy numbers, play important roles in genome evolution and diversification. AhMITE1 , a member of the MITE family of transposons, but information on the peanut genomes is still limited. Here, we analyzed AhMITE1 , AuMITE1 and ApMITE1 in the cultivated ( A. hypogaea ) and two wild peanut ( A. duranensis and A. ipaensis ) genomes. Results The cultivated and the two wild peanut genomes harbored 142, 14 and 21 AhMITE1 , AuMITE1 and ApMITE1 family members, respectively. These three family members exhibited highly conserved TIR sequences, and insertions preferentially occurred within 2 kb upstream and downstream of gene-coding and AT-rich regions. Phylogenetic and pairwise nucleotide diversity analysis showed that AhMITE1 and ApMITE1 family members have undergone one round of amplification bursts during the evolution of the peanut genome. PCR analyses were performed in 23 peanut varieties and demonstrated that AhMITE1 is an active transposon and that hybridization or chemical mutagenesis can promote the mobilization of AhMITE1 . Conclusions AhMITE1 , AuMITE1 and ApMITE1 family members were identified based on local BLAST search with MAK between the cultivated and the two wild peanut genomes. The phylogenetic, nucleotide diversity and variation copy numbers of AhMITE1 , AuMITE1 and ApMITE1 members provides opportunities for investigating their roles during peanut evolution. These findings will contribute to knowledge on diversity of AhMITE1 , provide information about the potential impact on the gene expression and promote the development of DNA markers in peanut.

Voltage-gated K+ channel β subunits act as a structural component of Kin channels in different species. The β subunits are not essential to the channel activity but confer different properties through binding the T1 domain or the C-terminal of α subunits. Here, we studied the physiological function of a novel gene, KIbB1, encoding a voltage-gated K+ channel β subunit in sweetpotato. The transcriptional level of this gene was significantly higher in the low-K+-tolerant line than that in the low-K+-sensitive line under K+ deficiency conditions. In Arabidopsis, KIbB1 positively regulated low-K+ tolerance through regulating K+ uptake and translocation. Under high-salinity stress, the growth conditions of transgenic lines were obviously better than wild typr (WT). Enzymatic and non-enzymatic reactive oxygen species (ROS) scavenging were activated in transgenic plants. Accordingly, the malondialdehyde (MDA) content and the accumulation of ROS such as H2O2 and O2− were lower in transgenic lines under salt stress. It was also found that the overexpression of KIbB1 enhanced K+ uptake, but the translocation from root to shoot was not affected under salt stress. This demonstrates that KIbB1 acted as a positive regulator in high-salinity stress resistance through regulating Na+ and K+ uptake to maintain K+/Na+ homeostasis. These results collectively suggest that the mechanisms of KIbB1 in regulating K+ were somewhat different between low-K+ and high-salinity conditions.

Peanut (Arachis hypogaea L.) is an allotetraploid oilseed crop worldwide due to its abundant high-quality oil production. Peanut oil stability and quality are determined by the relative proportions of saturated fatty acids (SFAs) and unsaturated fatty acids (UFAs). The principle approach to minimize the content of SFAs in peanut is to reduce the content of palmitic acid, which is linked to cardiovascular disease. Acyl-acyl carrier protein thioesterases (FATs) determine the types and levels of fatty acids that are exported them from the plastids. Two different classes of FAT have been classified into two families in plants, FatA and FatB. Among them, AhFatB has become the primary objective to genetically reduce the content of palmitic acid in peanut. Here, we identified 18 AhFatB genes in A. hypogaea genome and grouped into four major subfamilies through gene structures and phylogenetic relationships. Expression profiling of AhFatB genes was assessed using the publicly available RNA-seq data and qRT-PCR in 22 tissues. Using the CRISPR/Cas9 system, we designed two sgRNAs to edit the homologs AhFatB genes Arahy.4E7QKU and Arahy.L4EP3N, and identified different types of mutations. Additionally, we discovered mutations at Arahy.4E7QKU exhibited low palmitic acid and high oleic acid phenotypes. The obtained peanut mutants with altered SFAs content have great potential for improving peanut oil quality for human health.

花生(Arachis hypogaea L.)籽仁含油量是花生品质评价的重要指标,建立快速高效的含油量检测方法,对加快高油花生品种选育意义重大.本研究选用高油亲本宇花14(含油量59.32％)与低油亲本LOP215(含油量48.97％)杂交构建的RIL群体为建模材料,使用Thermo公司(美国)生产的AntarisⅡ型傅立叶变换近红外光谱分析仪对229份样品籽仁进行光谱采集,随后测定籽仁含油量.利用偏最小二乘法(partial least squares,PLS)构建花生籽仁含油量近红外定标模型,该模型的内部验证均方差(root mean square error of cross validation,RMSECV)为0.885,相关系数R2=0.9147.选用未参与建模的21份花生材料对该模型进行外部验证,模型预测值和化学测定值的决定系数R2=0.9492,表明该模型可适用于花生籽仁含油量检测.利用该模型对宇花14与LOP215杂交后代群体进行筛选,获得含油量超过55％的优良株系21个,含油量低于48％的株系9个,可为花生高低含油量品种选育提供种质材料.

Abiotic stressors, such as drought and high salinity, seriously affect plant growth, productivity, and quality. Maintaining reactive oxygen species (ROS) homeostasis and osmotic balance plays a crucial role in abiotic stress tolerance. β-amylase (BAM) hydrolyzes α-1,4-glycosidic bonds by releasing maltose from starch in the regulation of soluble sugars. However, the function and mechanism of BAMs related to abiotic stress resistance remain unclear in sweetpotato (Ipomoea batatas (L.) Lam.). In this study, we isolated a novel β-amylase gene IbBAM1.1, which was strongly induced by PEG6000, NaCl, and maltose treatments in sweetpotato variety Yanshu25. Overexpression of IbBAM1.1 conferred enhanced tolerance to the drought and high salinity stressors in Arabidopsis thaliana. The activity of β-amylase and the degradation of starch were promoted under drought or salt stress. Accordingly, the contents of osmoprotectants, including maltose and proline were significantly higher in the transgenic lines than those in wild type (WT) plants. Less ROS, such as H2O2 and O2-, accumulated in the overexpressing lines than in WT plants. Superoxide dismutase activity was strongly enhanced and the level of malondialdehyde was lower under the drought or salt treatment in transgenic plants. Taken together, these results demonstrate that IbBAM1.1 acted as a positive regulator, at least in part, by regulating the level of osmoprotectants to balance the osmotic pressure and activate the scavenging system to maintain ROS homeostasis in the plants.

淀粉和可溶性糖含量是影响甘薯品质的重要指标.本研究以5个鲜食型和4个淀粉型甘薯品种为材料,在不同时期(定植50 d、90 d、130 d)测定两种类型品种的淀粉和可溶性糖含量,结果发现,淀粉型品种的总淀粉、支链淀粉和直链淀粉含量在3个时期均极显著高于鲜食型品种,而可溶性总糖和蔗糖含量在3个时期均极显著低于鲜食型品种.可溶性总糖、蔗糖、果糖、葡萄糖、总淀粉、支链淀粉和直链淀粉含量在同一类型品种中的变化趋势一致(除'商薯19'外),且可溶性总糖、葡萄糖和直链淀粉含量在两种类型间有相似变化趋势.两种类型甘薯品种的总淀粉含量与支链淀粉含量呈极显著相关(p<0.01),蔗糖含量与果糖含量呈极显著相关(p<0.01).本研究为专用型甘薯新品种培育提供了基础.