Salt stress severely inhibits plant growth and negatively impacts crop yield. Auxin response factors (ARFs) play crucial roles in plant growth and development and are involved in multiple signaling pathways as well as responses to abiotic stresses. However, the molecular mechanisms by which ARFs mediate plant responses to salt stress and ABA signaling remain largely unclear. In this study, we cloned a novel tobacco ARF family gene, NtARF2, which is significantly downregulated under salt stress and exogenous ABA treatment. NtARF2 is localized in the nucleus, and its knockout increases the K/Na ratio and ABA content in tobacco, thereby markedly enhancing salt tolerance. Furthermore, NtARF2 knockout affects stomatal size, photosynthetic performance, and antioxidant capacity. Yeast two-hybrid (Y2H) and luciferase complementation imaging (LCI) assays indicate that NtARF2 interacts with NtABI3, suggesting that it may play a key role in the crosstalk between salt stress and ABA signaling pathways. This study provides new insights into the functional role of ARF2 in tobacco salt tolerance and offers a theoretical foundation for the development of salt-tolerant crop varieties.

Nicotine is the major alkaloid in tobacco and plays a key role in determining tobacco quality. Previous studies have shown that overexpression of NtGSTU10 enhances nicotine accumulation in tobacco hybrids; however, the molecular mechanisms underlying this process remain largely unclear. In this study, we investigated the regulatory role of NtGSTU10 in nicotine synthesis and distribution using integrated transcriptomic and metabolomic analyses in NtGSTU10-overexpressing tobacco plants. Nicotine content and distribution between roots and leaves were quantified, and global transcriptional and metabolic profiles were analyzed to reveal molecular changes associated with NtGSTU10 overexpression. The results showed that NtGSTU10 overexpression was associated with increased nicotine accumulation in leaves and reduced nicotine levels in roots, resulting in significantly higher nicotine transport coefficients compared with wild-type plants. Transcriptomic analysis revealed coordinated changes in genes involved in nicotine biosynthesis, transport, and secondary metabolism. Metabolomic profiling indicated significant alterations in amino acid metabolism, nicotinic acid and nicotinamide metabolism, purine metabolism, sugar metabolism, and alkaloid biosynthesis pathways. Integrated transcriptome–metabolome analysis further identified coordinated regulation of glutathione metabolism, ABC transporters, and MATE transporter–encoding genes. Overall, these results reveal a regulatory network associated with NtGSTU10-mediated nicotine biosynthesis and transport, providing new insights into the molecular mechanisms underlying nicotine metabolism in tobacco.

WGCNA mined the unknown gene NtLYK5, and VIGS and RNA-seq analyses suggested that NtLYK5 mediates the negative regulation of hydrogen peroxide production for drought resistance. Drought during the seedling stage of tobacco (Nicotiana tabacum), a water-sensitive and economically important crop, has serious adverse effects on transplant survival and tobacco plant growth. In this study, we conducted transcriptome sequencing on drought-tolerant and drought-sensitive recombinant inbred lines (RILs) from the F7 generation of the cross “NC82 × Bina No. 1.” Using weighted gene co-expression network analysis (WGCNA), BLAST alignment, bioinformatics analysis, and qRT-PCR, we identified a key candidate gene NtLYK5, which is highly associated with drought resistance but previously had an unknown function. Virus-induced gene silencing to suppress NtLYK5 expression in tobacco enhanced drought resistance, reduced hydrogen peroxide (H2O2) levels, and increased catalase (CAT) activity. Further transcriptomic analysis of drought-tolerant and drought-sensitive lines revealed differentially expressed genes (DEGs) associated with NtLYK5-induced drought resistance, which were significantly enriched in the MAPK signaling pathway. Under drought stress, H2O2 acts as a signaling molecule affecting the expression of DEGs such as ANP1, which induces H2O2 production and cell death, thereby preventing the stomata from closing properly. These results suggest that NtLYK5 is a key gene that negatively regulates drought tolerance in tobacco seedlings by modulating H2O2-induced stomatal movement.

The photothermal sensitivity of tobacco refers to how tobacco plants respond to variations in the photothermal conditions of their growth environment. The degree of this sensitivity is crucial for determining the optimal planting regions for specific varieties, as well as for improving the quality and yield of tobacco leaves. However, the precise mechanisms underlying the development of photothermal sensitivity in tobacco remain unclear. In this study, two tobacco varieties with significant differences in sensitivity, previously selected using a photothermal sensitivity model, were chosen as materials. Two experimental sites with considerable differences in photothermal conditions were selected for planting. The aim was to comparatively analyze the changes in agronomic traits, biomass, and physiological indices of the varieties under different experimental conditions, as well as to conduct transcriptome analyses. The transcriptome results revealed significant enrichment of differentially expressed genes (DEGs) related to photosynthesis, plant hormone signal transduction, and flavonoid biosynthesis pathways. In the photosynthesis and plant hormone signaling pathways, genes such as Lhcb, aldo, AUX/IAA, and SAUR were significantly upregulated. This upregulation promoted photosynthetic efficiency by enhancing the process of photosynthesis. However, this promotion also led to the increased production of harmful substances such as hydrogen peroxide and superoxide radicals, which can damage cellular structure and function. In the flavonoid biosynthesis pathway, genes such as FLS, CHI, and PAL were significantly upregulated, which enhanced the plant’s antioxidant capacity. This effectively mitigated the harmful effects of oxidative stress, helping to maintain normal photosynthetic function. The findings of this study suggest that the photosynthetic capacity of tobacco plants is enhanced through the coordinated regulation of the photosynthesis, plant hormone signaling, and flavonoid biosynthesis pathways. This enhancement plays a pivotal role in modulating the plants’ photothermal adaptability, ultimately contributing to variations in their photothermal sensitivity.

Tobacco (Nicotiana tabacum L.) is a crop of major economic importance worldwide and also a widely used model in plant biology and genetics. Leaf number (LN) is a key agronomic trait that determines yield. To elucidate its genetic basis, we developed a mapping population by crossing the low-leaf, high-quality cultivar 'NC82' with the high-leaf cultivar 'Jiucaiping No.2' (JCP2). Bulked segregant analysis initially placed the locus controlling LN within a 6.16 Mb region on chromosome 9. The integration of competitive allele-specific PCR markers with RNA sequencing data narrowed down this region and identified a single candidate gene, NtDEAH1. Overexpression of NtDEAH1 in both NC82 and JCP2 backgrounds significantly reduced LN, whereas CRISPR/Cas9-mediated knockout increased LN, indicating that NtDEAH1 acts as a negative regulator of LN and is a previously unreported control factor. Transcriptomic profiling and phytohormone analyses revealed that NtDEAH1 modulates the expression of genes in the gibberellin pathway. Specifically, NtDEAH1 binds to the 5'-untranslated region of the gibberellin receptor gene NtGID1, thereby influencing mRNA stability and translational efficiency to regulate LN. These findings provide new insights into genetic and molecular mechanisms underlying LN determination, and suggest that NtDEAH1 may serve as a target for future breeding aimed at optimising plant architecture and enhancing yield.

The photothermal sensitivity of tobacco refers to the degree to which tobacco responds to changes in light and temperature conditions in its growth environment, which is crucial for determining the planting area of cultivars and improving tobacco yield and quality. In order to accurately and effectively evaluate the photothermal sensitivity of tobacco cultivars, this study selected five cultivars and their hybrid combinations with significant differences planted under different ecological conditions from 2021 to 2022 as materials. The experiment was conducted in two locations with significant differences in temperature and light. We measured the agronomic traits and biomass of the experimental materials, and constructed an effective tobacco photothermal sensitivity evaluation model using principal component analysis, membership function, and regression analysis. The reliability of the model was evaluated by utilizing the photosynthetic characteristics, chlorophyll content, and antioxidant enzyme system activity of the experimental materials. The results showed that tobacco biomass is the most important principal component in agricultural traits, and the comprehensive evaluation model for tobacco photothermal sensitivity is: y = 0.4571y1 + 0.2406y2 + 0.1725y3, where the fitting coefficients R2 of y1, y2, and y3 are 0.945, 0.851, and 0.977, respectively; The photothermal sensitivity of the experimental materials was calculated using this model, and the comprehensive ranking of the 11 experimental materials is: G3 < G5 < G10 < G9 < G11 < G6 < G7 < G2 < G4 < G8 < G1. Conventional identification methods have found that G2, G4, G6, G7, G8, and G11 are sensitive materials, G3, G5, and G10 are insensitive materials, and G1 and G9 are intermediate materials. The consistency rate of the evaluation results of the two methods reached 90.91%. And there is a significant correlation between the agronomic traits selected in the model and the physiological indicators selected by conventional evaluation methods, providing a scientific basis for evaluating the light temperature sensitivity of tobacco cultivars using agronomic traits in this study. The results indicate that the photothermal sensitivity evaluation model established in this study provides an efficient, convenient, and reliable method for evaluating the photothermal sensitivity of tobacco.

[目的]鉴定评价不同来源晒黄烟种质资源,筛选出适宜贵州不同生态区的优质晒黄烟品种,为其在生产上的推广应用提供依据.[方法]采用随机区组试验方法,研究青梗、千层塔、腾冲大柳叶、羊角烟、连选1、81-26、湖北大黄烟、寸三皮、K16(CK1)和K17(CK2)10个引种晒黄烟主要农艺性状、经济性状、化学成分含量、抗病性、烟叶外观质量及感官质量的变化.[结果]10个晒黄烟品种除寸三皮和千层塔外大田主要生育期均较为适宜;腾冲大柳叶、湖北大黄烟和寸三皮的株型均为塔形,其余品种均为筒形;青梗的叶形为卵圆形,腾冲大柳叶为椭圆形,81-26和寸三皮均为长卵圆形,其余品种均宽椭圆形;羊角烟和寸三皮的叶色为深绿,青梗和千层塔为绿,81-26、K16和K17为浅绿,腾冲大柳叶、连选1和湖北大黄烟为黄绿;各品种株高、有效叶数、茎围、节距、腰叶长和腰叶宽分别为123.5～239.7 cm、11.7～20.8片、10.8～13.8 cm、3.0～6.6 cm、55.1～78.1 cm和32.4～48.7 cm,分别以青梗、K16(CK1)、81-26和湖北大黄烟最高/多/大/长/宽,寸三皮、千层塔和腾冲大柳叶最矮/少/小/短/窄.气候性斑点病、花叶病和白粉病均未发生.不同品种产量、均价和产值分别为 76.48～162.95 kg/667m2、12.11～22.64 元/kg 和 1 072.50～3 681.05 元/667m2,依次为寸三皮＞连选1＞81-26＞K16(CK1)＞K17(CK2)＞青梗＞千层塔＞湖北大黄烟＞羊角烟＞腾冲大柳叶、连选1＞腾冲大柳叶＞寸三皮＞K16(CK1)＞湖北大黄烟＞K17(CK2)＞青梗＞81-26＞羊角烟＞千层塔和连选1＞寸三皮＞K16(CK1)＞K17(CK2)＞81-26＞青梗＞腾冲大柳叶＞湖北大黄烟＞千层塔＞羊角烟.烟碱含量适宜的品种为湖北大黄烟和羊角烟,总糖和还原糖含量适宜的品种均为青梗和K17(CK2),总氮含量适宜的品种有千层塔、腾冲大柳叶、羊角烟、连选1、湖北大黄烟和寸三皮,钾含量适宜的品种有千层塔、腾冲大柳叶和湖北大黄烟,氯含量适宜的品种有千层塔和腾冲大柳叶.感官评吸质量综合表现较好的品种为青梗、连选1、81-26、寸三皮、K16(CK1)和K17(CK2).[结论]综合抗病性、外观质量、化学成分含量和感官评吸质量,连选1和寸三皮表现较好,K16和K17表现中等,81-26、青梗、腾冲大柳叶和湖北大黄烟表现一般,羊角烟和千层塔表现较差.

Tassel branch number is an important agronomic trait that is closely associated with maize kernels and yield. The regulation of genes associated with tassel branch development can provide a theoretical basis for analyzing tassel branch growth and improving maize yield. In this study. we used two high-generation sister maize lines, PCU (unbranched) and PCM (multiple-branched), to construct an F2 population comprising 190 individuals, which were genotyped and mapped using the Maize6H-60K single-nucleotide polymorphism array. Candidate genes associated with tassel development were subsequently identified by analyzing samples collected at three stages of tassel growth via RNA-seq. A total of 13 quantitative trait loci (QTLs) and 22 quantitative trait nucleotides (QTNs) associated with tassel branch number (TBN) were identified, among which, two major QTLs, qTBN6.06-1 and qTBN6.06-2, on chromosome 6 were identified in two progeny populations, accounting for 15.07% to 37.64% of the phenotypic variation. Moreover, we identified 613 genes that were differentially expressed between PCU and PCM, which, according to Kyoto Encyclopedia of Genes and Genomes enrichment analysis, were enriched in amino acid metabolism and plant signal transduction pathways. Additionally, we established that the phytohormone content of Stage I tassels and the levels of indole-3-acetic acid (IAA) and IAA-glucose were higher in PCU than in PCM plants, whereas contrastingly, the levels of 5-deoxymonopolyl alcohol in PCM were higher than those in PCU. On the basis of these findings, we speculate that differences in TBN may be related to hormone content. Collectively, by combining QTL mapping and RNA-seq analysis, we identified five candidate genes associated with TBN. This study provides theoretical insights into the mechanism of tassel branch development in maize.

为了明确'云烟121'在毕节烟区的推广利用价值,以云烟87(CK)为对照,从生育期、农艺性状、经济性状、化学成分及感官质量方面综合评价'云烟121'在黔西和威宁烟区的适应性.结果表明:'云烟121'在黔西和威宁烟区的大田生育期与CK相比没有差异;主要农艺性状在两个烟区表现相近,在黔西烟区表现稍好;在两个烟区的亩产量和亩产值表现均优于CK.综合化学成分表现和感官质量来看,'云烟121'在威宁烟区种植条件下化学成分更为协调,品质更好.综合表明,'云烟121'的经济性状、品质略优于对照'云烟87',适宜在毕节烟区种植,且在威宁烟区的烟叶亩产值、品质优于黔西烟区,说明更适宜于在威宁烟区推广种植.

为了探究苗期抗旱性快速评价方法,筛选烟草苗期抗旱材料,开展苗期抗旱种质鉴定和抗旱品种选育.本试验以 21 个品种(系)5 叶 1 心的烟苗为材料,采用 15%PEG-6000 模拟干旱胁迫处理,于处理 48h测定参试材料的叶绿素a等 10 项生理指标,通过主成分分析、隶属函数分析和通径分析构建了烟草苗期抗旱性评价方法.结果显示,主成分分析从 10 项指标中筛选出叶绿素a、H2 O2、MDA、SOD、POD等 5 项典型的抗旱指标;通过筛选出的 5 项指标与各材料D 值的通径分析构建出了烟草苗期抗旱性预测模型,模型表明叶绿素 a对烟草苗期抗旱性直接通径系数最大;分别以构建出的抗旱性预测模型和叶绿素 a的抗旱系数对各材料进行聚类分析,均将供试材料分为高抗型、中抗型、低抗型、不抗型和敏感型等 5 类,同时筛选出 4 份苗期抗旱性较强材料.研究表明,采用 15%PEG-6000 模拟干旱胁迫处理,利用叶绿素a等 5 项指标构建的抗旱性度量值及回归预测模型可用于烟草苗期抗旱性评价,干旱胁迫后叶绿素 a含量变化可用于快速鉴定烟草苗期抗旱性.

叶片数是影响烤烟(Nicotiana tabacum)产量的重要因素之一.为了提高叶片数遗传改良效率,本研究以少叶烤烟品种'NC82'和多叶烤烟品种'韭菜坪2号'为亲本,构建正反交F1和F2遗传群体,对'韭菜坪2号'烤烟叶片数进行遗传分析;利用基于极端混合池的全基因组重测序(bulked segregant analysis coupled with whole-genome sequencing,BSA-seq)和竞争性等位基因特异性PCR(kompetitive allele-specific PCR,KASP)技术进行'韭菜坪2号'叶片数的基因定位.结果表明,多叶烤烟品种'韭菜坪2号'的叶片数是主要由加性效应基因控制的数量性状,同时受到具有部分显隐性关系的基因调控,少叶对多叶是部分显性.利用BSA-seq技术进行初定位,结合测序所得的Δ(SNP-index)位点和欧式距离(euclidean distance,ED)位点关联分析,将叶片数候选区间定位于第9号染色体的6.96 Mb区间内;根据重测序获得的SNP位点基因型,在候选区间开发KASP标记检测F2单株基因型,进一步将叶片数候选基因缩小到1.92 Mb区间内,该区间包含37个基因;对该区间内的基因进行序列分析和功能预测,推测控制'韭菜坪2号'叶片数性状的关键基因可能在该区间的8个基因之中.本研究为进一步明确调控'韭菜坪2号'烤烟叶片数的关键基因、提高烤烟产量育种效率和揭示烤烟叶片数形成的分子机理提供基础资料.

为评价不同烤烟品种在毕节烟区的生态适应性,以云烟 87 为对照,对CF8704、云烟 121、贵烟 4 号、HB202、GZ36 和云烟 301 等 6 个品种进行试验,研究各品种农艺性状、经济性状、化学成分和感官质量的差异,并采用Topsis法进行综合评价.结果表明,CF8704、贵烟 4 号和云烟 121 农艺性状表现较好;云烟 121 的均价和上等烟率最高,CF8704 和云烟 121 经济性状表现较好;各品种烟叶化学成分整体协调,以GZ36、云烟121 和云烟 301 表现较好;感官质量以云烟 121 和GZ36 表现较好.各品种综合评价排名云烟 121 第一,其余品种低于对照云烟 87,说明云烟 121 适宜在毕节烟区种植.

Phosphorus (P) is a critical nutrient for plants, and inorganic orthophosphate (Pi) deficiency results in declining crop quality and yields. Auxin plays a key regulatory effect on plant growth in response to Pi deficiency, yet the regulatory mechanisms remain poorly understood. In this study, we cloned and identified an auxin efflux transporter, NtPIN3, involved in the low phosphate response of tobacco (Nicotiana tabacum). NtPIN3 is located on the cytoplasmic membrane, and high expression levels of NtPIN3 were observed under phosphorus deficiency conditions. Moreover, NtPIN3 overexpression in tobacco could dramatically enhance low Pi tolerance by increasing the root length, which was consistent with the GUS activity and the auxin concentration in the root. Notably, Pi concentration and antioxidant capacity in overexpression transgenic tobacco were significantly increased compared with the wild type (WT) under low Pi stress conditions due to Pi uptake (NtPT1 and NtPT2) and antioxidant capacity (superoxide dismutase, peroxidase, and catalase). In contrast, compared with WT, the ntpin3 mutant significantly reduced root length, auxin concentration, Pi concentration, and antioxidant capacity under low Pi stress conditions, suggesting that NtPIN3 is a positive regulator of low phosphate in tobacco. In addition, the yeast-two-hybrid and luciferase complementation imaging assay confirmed that NtPIN3 interacted with NtPIN2. Altogether, the NtPIN3 involved in low Pi response and overexpression of NtPIN3 contributed to enhanced tolerance to low Pi stress, which proved an underlying gene for breeding low Pi-stress tolerant plants.

目前我国烟草杂交种种植越发广泛,不育系作为制备烟草杂交种的有利材料,在我国烟草种植中具有重要地位.为了探究烟草胞质雄性不育形成的分子机制,选用烟草不育系及其保持系,在花芽分化时期利用石蜡切片和线粒体蛋白组学技术结合生物信息学分析方法进行研究.结果表明,烟草雄性不育系的败育过程发生在发芽分化的雌雄蕊原基分化时期;蛋白组学分析共筛选出线粒体差异表达蛋白113个,呼吸代谢过程中的焦磷酸酶、异柠檬酸脱氢酶、苹果酸脱氢酶和磷酸己糖异构酶等关键调控蛋白酶的表达显著下调,ATP合酶的δ和α亚基表达上调;在线粒体蛋白的合成、修饰和运输过程中,核糖体RNA大亚基中L4e、L7和小亚基中SAe的表达下调,烯醇酶、内质网蛋白加工酶、蛋白二硫键异构酶等功能蛋白结构修饰酶表达下调,蛋白酶复合体的Rpt3和α5亚基表达下调.由上述结果推测,烟草胞质雄性不育由于线粒体蛋白的合成、修饰及导入过程受阻使线粒体功能紊乱,具体表现在线粒体呼吸代谢途径的蛋白酶表达下调及合成ATP受阻,不能为其在花粉形成时期小孢子的快速分裂分化提供充足的能量,抑制了小孢子的形成和发育,从而表现为雄性不育.本研究结果为进一步开展烟草雄性不育机理研究奠定了重要基础.

为筛选适合毕节烟区生态条件的烤烟新品种,2020年在毕节市田坝桥镇以K326和云烟87为对照,对10个烤烟新品种的农艺性状、经济性状及烟叶质量进行比较分析,并采用灰色关联度分析法进行综合评价.结果表明:GZ39和GZ37综合农艺性状较好,GZ37、GZ39和CF235的产量、产值较高;各品种烟叶外观质量均优于对照K326,烟叶化学成分整体协调;GZ21的感官质量与云烟87相当,其余品种与K326相当;GZ37和GZ39的等权关联度值分别为12.0102、11.2116,明显高于其他品种.综合分析,GZ37和GZ39的综合表现较好,可在毕节烟区进一步示范推广.

本文通过田间试验研究比较了 9个烤烟品种的生育期、农艺性状、经济性状、外观质量、化学成分及感官质量差异.结果表明,云烟207和9011的大田生育期最长,云烟207的打顶株高最高,有效叶数最多,HB030和云烟121的最大叶长较大,9011和贵烟5号最大叶宽较大;云烟210和云烟121的产量最高,云烟121和CF228的产值最高,A28的产量、产值均最低;云烟207和云烟210的外观质量较好,CF228和A28较差;各品种烟叶化学成分整体协调,9011、云烟210和K326的烟碱含量较高,云烟207和贵烟5号的钾含量较高,CF228和HB030的糖碱比较高,9011的糖碱比和氮碱比较低;各品种感官质量与K326相当,A28最差.综合表现以云烟121、云烟210和HB030最好.

为了筛选出适合毕节烟区的烤烟品种,以云烟87和K326为对照,对8个烤烟品种进行小区比较试验,分析了它们在生育期、植物学性状、农艺性状、抗病性、经济性状、化学成分及感官质量方面的差异,并采用灰色关联度分析法对其进行了综合评价.结果表明:NC102、CC27、云烟105和贵烟202的农艺性状较好;NC102、CC27、云烟116和贵烟202的综合抗病性较强;NC102、贵烟202和CC27的产值较高;贵烟202的感官质量最好;C102、贵烟202和CC27的等权关联度值分别为10.5009、10.3156、10.2286,明显大于对照云烟87和K326,说明NC102、贵烟202和CC27的综合表现较好.

[背景和目的]低亲和硝酸盐转运蛋白NRT1家族基因在植物吸收和转运硝态氮过程中发挥重要作用,为研究烟草NRT1家族基因在烟草氮素利用中的作用.[方法]从栽培烟草品种K326中克隆获得NtNRT1.5的全长cDNA序列,利用生物信息分析、qRT-PCR技术和转基因技术系统分析NtNRT1.5基因的序列特征、表达模式及在提高烟草氮素利用效率方面的功能.[结果]NtNRT1.5全长序列包含1800 bp开放阅读框、编码599个氨基酸,编码的蛋白质具有NRT基因家族的共有结构特征,与拟南芥AtNRT1.5相似性达到59.28％.亚细胞定位结果表明NtNRT1.5蛋白定位在细胞膜上,其启动子中包含多个与硝酸盐(A(C/G)TCA)、胁迫(MYB)、根系特异表达(ROOT MOTIF BOX)相关的响应元件.表达模式分析结果表明iVtNRT1.5主要在根部表达,其次是衰老叶片和茎,新叶基本不表达;低氮抑制其在根系中的表达,说明NtNRT1.5主要负责正常条件下的硝酸盐的吸收;低氮条件下,NtNRT1.5过表达显著提高了转基因烟株的氮素利用率.[结论]NtNRT1.5基因在烟草氮素的吸收和转运上行使重要功能,通过提高过表达烟草的氮素利用率,增加植株的生物量.本研究为后期培育烟草氮高效利用新品种提供了理论依据.

Salt stress can retard plant growth and reduce crop yields. Genes in the auxin-responsive Aux/IAA family play key roles in regulating plant growth and development. However, the molecular mechanisms of Aux/IAA proteins underlying growth regulation in response to salt stress remain unclear. In Nicotiana tabacum , we identified an AUX/IAA family gene, NtIAA26 , that exhibited significantly upregulated expression under salt stress. The NtIAA26-GFP fusion protein was located in the nucleus, suggesting that NtIAA26 functions as a transcriptional activator in tobacco. Notably, NtIAA26 overexpression substantially increased K + uptake, reduced Na + accumulation, enhanced antioxidant activity, and improved salt stress resistance in tobacco plants. Under salt stress, the expression levels of several K + transporter genes (e.g., NtHAK5 and NtHAK11 ) and antioxidant-related genes (e.g., NtSOD , NtPOD , NtAPX , and NtP5CS ) were higher in NtIAA26 overexpressing transgenic plants than in wild-type plants. Taken together, these findings provide novel insights into the functioning of NtIAA26 in the regulation of salt stress responses in tobacco and indicate that NtIAA26 may be a candidate for improving crop salt tolerance.

含梗率是烟叶的重要经济性状和物理特性指标,其测定方法过程繁琐、时间长,在品种选育中难以应用于大量品系鉴定和选择.为快速地测定含梗率,本研究设置杀青和烘烤干燥方式、叶梗分离和不分离处理以及0、5％、10％、15％和20％共5种烤后烟叶平衡含水率处理,测定不同品种间各处理的烟叶含梗率.结果表明,不同品种间烟叶含梗率相差极显著,烟草叶片梗的生长发育受遗传控制,说明选育含梗率低的品种是降低烟叶含梗率的有效途径;采用烘烤干燥方式的烟叶含梗率极显著高于杀青干燥方式,两种干燥方式间的烟叶含梗率差异极显著,相关系数为0.98,回归方程为y=1.615 9x+5.203 9;叶梗分离和不分离干燥后的烟叶含梗率差异极显著,叶梗分离后杀青干燥与不分离烘烤的烟叶含梗率的差异达到极显著水平,相关系数为0.93,回归方程为y=1.2299x-2.0705;当含水率在0～20％时,烟叶含梗率测定结果差异不显著.因此,在研究烟叶含梗率的遗传和进行新品系烟叶含梗率鉴定选择时,可采用将成熟烟叶的叶梗分离后进行杀青干燥,冷却后即可测定烟叶含梗率,根据测定值与对照品种烟叶含梗率的高低进行取舍,或采用回归方程预测该品系烘烤后的烟叶含梗率.成熟烟叶叶梗分离后杀青干燥测定烟叶含梗率的方法能提早鉴定时间、提高鉴定效率,可及时、快速、准确地对育种材料烟叶含梗率进行鉴定选择.