Characterization of the role of Smu1 in nuclear localization of splicing factors in the mammalian temperature-sensitive mutant

A temperature-sensitive (ts) mutant of the CHO-K1 cell line, tsTM18, grows at 340C but not at 390C. Smu1 is the gene responsible for ts defects of tsTM18 cells. Previously, we found that the Smu1 ts defect altered the localization (as indicated by enlargement of speckles) of SRSF1 (SF2/ASF) in tsTM18 cells cultured at 390C, suggesting a functional association between Smu1 and SRSF1. Speckles are subnuclear structures that may function as storage/assembly/ modification compartments to supply splicing factors to active transcription sites. The effect of the ts defect of Smu1 on the localization of other factors related to splicing has not been characterized yet. The mechanisms underlying the enlargement of speckles of SRSF1 remain unclear. In the present study, we found that the ts defect of Smu1 affected the nuclear localization of a splicing factor, SRSF2 (SC35), and factors involved in the exon-exon junction complex, Y14 and ALY. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that the ts defect of Smu1 affected alternative splicing of endogenous Clk1/ Sty and SRSF2 genes. Mammalian Clk family kinases are shown to phosphorylate serine/arginine (SR) proteins in vitro and SRSF1 in vivo. RT-PCR analysis of Clk1/Sty showed an accumulation of the truncated form lacking kinase activity in tsTM18 cells incubated at 39?C. These data indicate that an accumulation of kinase-negative Clk1/Sty may lead to alteration of the localization of factors related to splicing resulting in the enlargement of speckles.

A novel transcription factor FnMYB4 regulates pigments metabolism of yellow leaf mutants in Fragaria nilgerrensis

The strawberry species Fragaria nilgerrensis Schlechtendal ex J.Gay,renowned for its distinctive white,fragrant peach-like fruits and strong disease resistance,is an exceptional research material.In a previous study,an ethyl methane sulfonate(EMS)mutant library was established for this species,resulting in various yellow leaf mutants.Leaf yellowing materials are not only the ideal materials for basic studies on photosynthesis mechanism,chloroplast development,and molecular regulation of various pigments,but also have important utilization value in ornamental plants breeding.The present study focused on four distinct yellow leaf mutants:mottled yellow leaf(MO),yellow green leaf(YG),light green leaf(LG),and buddha light leaf(BU).The results revealed that the flavonoid content and carotenoid-to-chlorophyll ratio exhibited a significant increase among these mutants,while experiencing a significant decrease in chlorophyll and carotenoid contents compared to the wild type(WT).To clarify the regulatory mechanisms and network relationships underlying these mutants,the RNA-seq and weighted gene coexpression network(WGCNA)analyses were employed.The results showed flavonoid metabolism pathway was enriched both in MO and YG mutants,while the chlorophyll biosynthesis pathway and carotenoid degradation pathway were only enriched in MO and YG mutants,respectively.Subsequently,key structural genes and transcription factors were identified on metabolic pathways of three pigments through correlation analyses and quantitative experiments.Furthermore,a R2R3-MYB transcription factor,FnMYB4,was confirmed to be positively correlated with flavonoid synthesis through transient overexpression,virus-induced gene silencing(VIGS),and RNA interference(RNAi),accompanying by reoccurrence and attenuation of mutant phenotype.Finally,dual-luciferase(LUC)and yeast one-hybrid assays confirmed the binding of FnMYB4 to the FnFLS and FnF3H promoters,indicating that FnMYB4 positively regulates flavonoid synthesis.In addition,correlation analyses suggested that FnMYB4 also might be involved in chlorophyll and carotenoid metabolisms.These findings demonstrated the pivotal regulatory role of FnMYB4 in strawberry leaf coloration.

Detection of ARV-Resistant Mutants in HIV-1-Infected Individuals in a Context of Systematic Switching to an Association Based on Dolutegravir in Abidjan, Côte d’Ivoire

The emergence of antiretroviral resistance mutations represents a major threat to the achievement of national and global goals for the elimination of HIV-1 infection. The global strategy in 2019 in Cte d'Ivoire is a new national policy for the management of people living with HIV with the administration of dolutegravir (DTG)-based fixed-dose combination. The aim of our study was to evaluate HIV-1 resistance to antiretrovirals (ARVs) in infected adult subjects in Cte d’Ivoire in the context of a systematic switch to a DTG-based combination. Between February 2022 and October 2023, a cross-sectional survey with random sampling was conducted in 06 services caring for people living with HIV. A total of 139 participants were included in the study. Adults with a viral load ≥ 1000 copies/mL were tested for HIV-1 ARV resistance mutations. Molecular analyses were performed using protocol of ANRS-MIE (National Agency for Research on AIDS and emerging infectious diseases). The interpretation is performed by HIVGRAD (https://www.hiv-grade.de/cms/grade/). The frequencies of HIV-1 resistance to non-nucleotide reverse transcriptase inhibitors (NNRTIs), nucleotide reverse transcriptase inhibitors (NRTIs), integrase inhibitors (IINTs) and protease inhibitors (PIs) were 82%, 73%, 19% and 11% respectively. The main mutations observed in the different classes were K103N (45%), M184V (64%), E157Q (19%) and L10V/M46I/A71V/I54V (6%) respectively. This study reveals the emergence of resistance to DTG-based fixed-dose combinations, favored by high rates of resistance to NRTIs and NNRTIs. This finding underlines the need for enhanced viral load monitoring and HIV-1 genotyping tests to guide the choice of NRTIs for combination therapy. In addition, monitoring for mutations to second-generation NRTIs is essential, given the scale-up of DTG-based regimens currently underway in Cte d’Ivoire.

An efficient method for constructing a random insertional mutant library for forward genetics in Nannochloropsis oceanica

Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from scratch.Exogenous genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-strand breaks of DNA,causing insertional mutation.The random insertional mutant library constructed using this method has become a method of forward genetics for gene cloning.However,the establishment of a random insertional mutant library requires a high transformation efficiency of exogenous genes.Many microalgal species show a low transformation efficiency,making constructing random insertional mutant libraries difficult.In this study,we established a highly efficient transformation method for constructing a random insertional mutant library of Nannochloropsis oceanica,and tentatively tried to isolate its genes to prove the feasibility of the method.A gene that may control the growth rate and cell size was identified.This method will facilitate the genetic studies of N.oceanica,which should also be a reference for other microalgal species.

Pichia pastoris composition expressed aerolysin mutant of Aeromonas veronii as an oral vaccine evaluated in zebrafish(Danio rerio)

Vaccines are one of the most practical means to stop the spreading of Aeromonas veronii in aquaculture.In this study,virulence factor aerolysin mutant NTaer which has lost its hemolytic activity was used as a target antigen.Pichia pastoris constitutive secretory expression NTaer(GS115-NTaer)was used as a potential safe oral vaccine to evaluate its effectiveness on zebrafish immunity.The result shows that vaccination of GS115-NTaer for four weeks did not affect the growth performance of the host,while eliciting an effective immune protective response.Compared with the control group,the GS115-NTaer could significantly up-regulate the relative expression level of the intestinal tight junction protein 1α(TJP1α)gene,and significantly increased the contents of lysozyme(LYZ),complement C3 and C4 in the gut,indicating that the innate immune response of the fish was activated.The relative gene expression levels of macrophage-expressed gene 1(MPEG1)and T cell receptor(TCR-α)in the gut,and MPEG1,CD4,CD8,TCR-α,GATA3,and T-bet in the spleen were all increased significantly,indicating that the cellular immune response of the fish was activated.Furthermore,the contents of serum IgM and intestinal mucosa IgZ antibodies were significantly increased,which showed that humoral immunity was also activated.Moreover,inoculation with GS115-NTaer significantly changed the structure of gut microbiota.In particular,the relative ratio of(Firmicutes+Fusobacteriota+Bacteroidota)/Proteobacteria was significantly higher than that of the control and GS115 groups.Lastly,the vaccinated fish were challenged with A.veronii,and the relative percent survival of GS115 and the GS115-NTear groups was 14.28%and 33.43%.This improvement of immunity was not only due to the specific immune response but also attributed to the improvement of innate immunity and the gut microbiota which was demonstrated by the germ-free zebrafish model.Collectively,this study provides information on the effectiveness of GS115-NTear as an oral vaccine for the green prevention and control of A.veronii infection in fish aquaculture.

Roles of Mutant TP53 Gene in Cancer Development and Progression

TP53 is a tumor suppressor gene that is mutated in most cancer types and has been extensively studied in cancer research.p53 plays a critical role in regulating the expression of target genes and is involved in key processes such as apoptosis,cell cycle regulation,and genomic stability,earning it the title“guardian of the genome.”Numerous studies have demonstrated p53’s influence on and regulation of autophagy,ferroptosis,the tumor microenvironment,and cell metabolism,all of which contribute to tumor suppression.Alterations in p53,specifically mutant p53(mutp53),not only impair its tumor-suppressing functions but also enhance oncogenic characteristics.Recent data indicate that mutp53 is strongly associated with poor prognosis and advanced cancers,making it an ideal target for the development of novel cancer therapies.This review summarizes the post-translational modifications of p53,the mechanisms of mutp53 accumulation,and its gain-of-function,based on previous findings.Additionally,this review discusses its impact on metabolic homeostasis,ferroptosis,genomic instability,the tumor microenvironment,and cancer stem cells,and highlights recent advancements in mutp53 research.

Thermal Error Modeling Method with the Jamming of Temperature-Sensitive Points'Volatility on CNC Machine Tools

Aiming at the deficiency of the robustness of thermal error compensation models of CNC machine tools, the mechanism of improving the models＇ robustness is studied by regarding the Leaderway-V450 machining center as the object. Through the analysis of actual spindle air cutting experimental data on Leaderway-V450 machine, it is found that the temperature-sensitive points used for modeling is volatility, and this volatility directly leads to large changes on the collinear degree among modeling independent variables. Thus, the forecasting accuracy of multivariate regression model is severely affected, and the forecasting robustness becomes poor too. To overcome this effect, a modeling method of establishing thermal error models by using single temperature variable under the jamming of temperature-sensitive points＇ volatility is put forward. According to the actual data of thermal error measured in different seasons, it is proved that the single temperature variable model can reduce the loss of fore- casting accuracy resulted from the volatility of tempera- ture-sensitive points, especially for the prediction of cross quarter data, the improvement of forecasting accuracy is about 5 μm or more. The purpose that improving the robustness of the thermal error models is realized, which can provide a reference for selecting the modelingindependent variable in the application of thermal error compensation of CNC machine tools.

Plant Temperature for Sterile Alteration of a Temperature-Sensitive Genic Male Sterile Rice,Peiai64S

The forecast of sterile alteration for the temperature-sensitive genic male sterile （TGMS） line in two-line hybrid rice seed production was traditionally based on screen temperature determined by weather station. The article put forward a new approach based on plant temperature, which was more exact and direct than the traditional method. The result of the simulation of the self-seeded setting rate of a widely used TGMS line, Peiai64S, by several temperature parameters and durations, showed that the fertility was directly affected by the plant temperature at a height of 20 cm or the air temperature around it in three days duration. Using the stem temperature of three days at a height of 20 cm as the simulation parameter, the fertility of Peiai64S had the maximum, minimum and optimum temperatures as 22.8, 21.7 and 22.5℃, respectively, whereas 23.2, 21.5 and 21.8℃ when using the air temperature of three days around the height of 20 cm as the parameter. Such temperature indices can be used to conclude the sterile alteration of TGMS for safeguarding seed production of twoline hybrid rice. The article also established a statistic model to conclude plant temperature by water temperatures at inflow and outflow, and air temperature and cloudage from weather station.

Variations in chlorophyll content, stomatal conductance, and photosynthesis in Setaria EMS mutants

Chlorophyll (Chl) content,especially Chl b content,and stomatal conductance (G_s) are the key factors affecting the net photosynthetic rate (P_n).Setaria italica,a diploid C_4 panicoid species with a simple genome and high transformation efficiency,has been widely accepted as a model in photosynthesis and drought-tolerance research.The current study characterized Chl content,G_s,and P_n of 48 Setaria mutants induced by ethyl methanesulfonate.A total of 24,34,and 35 mutants had significant variations in Chl content,G_s,and P_n,respectively.Correlation analysis showed a positive correlation between increased G_s and increased P_n,and a weak correlation between decreased Chl b content and decreased P_n was also found.Remarkably,two mutants behaved with significantly decreased Chl b content but increased P_n compared to Yugu 1.Seven mutants behaved with significantly decreased G_s but did not decrease P_(n )compared to Yugu 1.The current study thus identified various genetic lines,further exploration of which would be beneficial to elucidate the relationship between Chl content,G_s,and P_n and the mechanism underlying why C_4 species are efficient at photosynthesis and water saving.

Preparation and Properties of Hydroxyethyl Methacrylate Chemically Modified Temperature-Sensitive Microgels

A novel series of poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) (p(NIPAM-co-HEMA)) microgels were prepared through precipitation polymerization. Nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV) and dynamic light scattering (DLS) were employed to characterize the microgels. The experimental results indicate that the prepared microgels with narrow distribution remain good temperature sensitivity after incorporation of functional-OH groups. In marked contrast to the general rule, incorporation of hydrophilic HEMA makes the volume-phase-transition temperature shift to the lower temperature due to the strong intermolecular H-bonding between amide and -OH groups, -OH and -OH groups.

Synthesis and characteristics of pH-and temperature-sensitive hydrogels of poly （DMAEMA/NIPAAm）

A kind of novel copolymer hydrogel of poly（N, N-dimethylaminoethyl methacrylate-co-N-isopropylacrylamide） （poly[DMAEMA/NIPAAm]） was synthesized by the initiation of K2S2O8, N, N＇-methylene-bis（acrylamide） （Bis） was used as the crosslinker. The effects of monomer content, pH and temperature on swelling ratio of the hydrogel were investigated; the thermo-sensitivity in deionized water and in physiological saline was determined. It showed that the swelling ratio of the hydrogel could be changed by changing the temperature or pH alternately. Both swelling ratio and LCST （Lower Critical Solution Temperature） of the hydrogel decreased with the increase of NIPAAm in the co-polymer content.

Finite deformation swelling of a temperature-sensitive hydrogel cylinder under combined extension-torsion

The swelling behavior of a temperature-sensitive poly-N-isopropylacrylamide(PNIPAM) hydrogel circular cylinder is studied subjected to combined extension-torsion and varied temperature. In this regard, a semi-analytical solution is proposed for general combined loading. A finite element(FE) analysis is conducted, subjecting a hydrogel cylinder to the combined extension-torsion and the varied temperature to evaluate the validity and accuracy of the solution. A user-defined UHYPER subroutine is developed and verified under free and constrained swelling conditions. The FE results illustrate excellent agreement with the semi-analytical solution. Due to the complexity of the problem, some compositions and applied loading factors are analyzed. It is revealed that for larger cross-linked density and larger ending temperature, the cylinder yields higher stresses and smaller radial swelling deformation. Besides, the radial and hoop stresses increase by applying larger twist and axial stretch. The hoop stresses intersect at approximately R/Rout = 0.58, where the hoop stress vanishes. Besides, the axial force has direct and inverse relationships with the axial stretch and the twist, respectively. However, the resultant torsional moment behavior is complex, and the position of the maximum point varies significantly by altering the axial stretch and the twist.

Construction of EMS-Induced Peanut Mutant Libraries and Identification of Pod-Related Traits Mutant Lines

Peanut(Arachis hypogaea L.)is an oil and economic crop of vital importance,and peanut pod is the key organ influencing the yield and processing quality.Hence,the Pod-related traits(PRTs)are considered as important agronomic traits in peanut breeding.To broaden the variability of PRTs in current peanut germplasms,three elite peanut cultivars were used to construct Ethyl methane sulfonate(EMS)-induced mutant libraries in this study.The optimal EMS treatment conditions for the three peanut varieties were determined.It was found that the median lethal dose(LD50)of EMS treatment varied greatly among different genotypes.Finally,the EMS-induced peanut mutant libraries were constructed and a total of 124 mutant lines for PRTs were identified and evaluated.Furthermore,“M-8070”,one of the mutant lines for pod constriction,was re-sequenced via high-throughput sequencing technology.The genome-wide variations between“M-8070”and its wild parent“Fuhua 8”(FH 8)were detected.2994 EMS-induced single nucleotide polymorphisms(SNPs)and 1188 insertion-deletions(InDels)between“M-8070”and its wild parent were identified.The predominant SNP mutation type was C/G to T/A transitions,while the predominant InDel mutation type was“1-bp”.We analyzed the distribution of identified mutations and annotated their functions.Most of the mutations(91.68%of the SNPs and 77.69%of the InDels)were located in the intergenic region.72 SNPs were identified in the exonic region,leading to 27 synonymous,43 nonsynonymous and 2 stop-gain variation for gene structure.13 Indels were identified in the exonic region,leading to 4 frame-shift,8 non-frame-shift and 1 stop-gain variations of genes.These mutations may lead to the phenotypic variation of“M-8070”.Our study provided valuable resources for peanut improvement and functional genomic research.

Transcriptome Analysis of Molecular Mechanisms Underlying Phenotypic Variation in Phaseolus vulgaris Mutant‘nts’

The phenotype of a common bean plant is often closely related to its yield,and the yield of plants with reduced height or poor stem development during growth is low.Mutants serve as an essential gene resource for common bean breeding genetic research.Although model plants and crops are studied to comprehend the molecular mechanisms and genetic basis of plant phenotypes,the molecular mechanism of phenotypic variation in common beans remains underexplored.We here used the mutant‘nts’as material for transcriptome sequencing analysis.This mutant was obtained through 60Co-γirradiation from the common bean variety‘A18’.Differentially expressed genes were mainly enriched in GO functional entries such as cell wall organization,auxin response and transcription factor activity.Metabolic pathways significantly enriched in KEGG analysis included plant hormone signal transduction pathways,phenylpropanoid biosynthesis pathways,and fructose and mannose metabolic pathways.AUX1(Phvul.001G241500),the gene responsible for auxin transport,may be the key gene for auxin content inhibition.In the plant hormone signal transduction pathway,AUX1 expression was downregulated and auxin transport across the membrane was blocked,resulting in stunted growth of the mutant‘nts’.The results provide important clues for revealing the molecular mechanism of‘nts’phenotype regulation in bean mutants and offer basic materials for breeding beneficial phenotypes of bean varieties.

Mapping and Functional Analysis of LE Gene in a Lethal Etiolated Rice Mutant at Seedling Stage

An EMS(ethy methanesulfonate)-induced lethal etiolated(le)mutant obtained from the rice variety Zhongjian 100 was characterized by lethal etiolated phenotypes,with significantly reduced levels of chlorophyll a,chlorophyll b,total chlorophyll,and carotenoids.Additionally,the mutant displayed a significantly decreased number of chloroplast grana,along with irregular and less-stacked grana lamellae.The le mutant showed markedly diminished root length,root surface area,and root volume compared with the wild type.It also exhibited significantly lower catalase activity and total protein content,while peroxidase activity was significantly higher.Using the map-based cloning method,we successfully mapped the LE gene to a 48-kb interval between markers RM16107 and RM16110 on rice chromosome 3.A mutation(from T to C)was identified at nucleotide position 692 bp of LOC_Os03g59640(ChlD),resulting in a change from leucine to proline.By crossing HM133(a pale green mutant with a single-base substitution of A for G in exon 10 of ChlD subunit)with a heterozygous line of le(LEle),we obtained two plant lines heterozygous at both the LE and HM133 loci.Among 15 transgenic plants,3 complementation lines displayed normal leaf color with significantly higher total chlorophyll,chlorophyll a,and chlorophyll b contents.The mutation in le led to a lethal etiolated phenotype,which has not been observed in other ChlD mutants.The mutation in the AAA+domain of ChlD disrupted the interaction of ChlDle with ChlI as demonstrated by a yeast two-hybrid assay,leading to the loss of ChlD function and hindering chlorophyll synthesis and chloroplast development.Consequently,this disruption is responsible for the lethal etiolated phenotype in the mutant.

靶向敲除棉花GhAGL16高效sgRNA的筛选

【目的】AGL16是棉花MADS-box基因家族中一个重要的转录负调控因子,在抵御干旱和盐胁迫过程中发挥着重要作用。利用病毒介导的基因编辑技术(virus-induced gene editing,VIGE)筛选靶向敲除棉花GhAGL16的sgRNAs,并验证这些sgRNAs的特异性,为定向创制棉花agl16突变体奠定重要基础。【方法】根据在棉花YZ-1中A亚组和D亚组上实际克隆GhAGL16的基因组序列,预测了3个能靶向敲除GhAGL16的sgRNAs;基于棉花叶皱缩病毒(cotton leaf crumple virus,CLCrV)介导的VIGE系统,构建3个CLCrV-AtU6-26::GhAGL16-sgRNAs表达载体;利用qPCR检测Cas9超表达(Cas9 over-expression,Cas9-OE)植株中Cas9的表达量,确定Cas9是否稳定遗传表达;将3个CLCrV-AtU6-26::GhAGL16-sgRNAs表达载体分别转化Cas9-OE棉花子叶,并通过PCR/RE方法检测3个靶点的突变情况;利用生物信息学方法分析3个GhAGL16-sgRNAs的二级结构;对突变植株进行Hi-TOM高通量测序,明确基因编辑效率。同时,对转化GhAGL16-sgRNA2的突变植株进行脱靶率鉴定,检测基因编辑的特异性。【结果】成功构建了3个能同时靶向敲除GhAGL16-A亚组和GhAGL16-D亚组序列的sgRNAs。对不同Cas9-OE植株中Cas9表达量检测结果表明,Cas9在不同Cas9-OE棉株中稳定表达。用3个CLCrV-AtU6-26::GhAGL16-sgRNAs表达载体转化Cas9-OE棉花子叶,PCR/RE突变检测结果表明,GhAGL16-sgRNA2可有效用于GhAGL16的靶向敲除,在棉花A亚组和D亚组靶位点上出现了不同碱基缺失的突变类型,而GhAGL16-sgRNA1和GhAGL16-sgRNA3是2个无效sgRNA。3个GhAGL16-sgRNAs的二级结构分析结果表明,GhAGL16-sgRNA1和GhAGL16-sgRNA3可能存在引导序列容易与其他序列发生配对并且不易解链的现象,干扰了引导序列对目标位点的识别,导致sgRNA无效。进一步量化GhAGL16-sgRNA2对GhAGL16的编辑效率,对每一株转化CLCrV-AtU6-26::GhAGL16-sgRNA2的Cas9-OE植株突变检测结果表明,在转化的9株Cas9-OE植株中有6株发生了突变,突变效率为66.67%。此外,Hi-TOM高通量测序结果表明,GhAGL16-sgRNA2对GhAGL16的编辑效率为13.69%—54.42%。脱靶率鉴定结果表明,预测的4个潜在脱靶位点都没有发现脱靶现象,说明GhAGL16-sgRNA2不仅具有高效的基因编辑效率,而且具有专一的基因编辑特异性。【结论】利用CLCrV介导的VIGE系统转化Cas9-OE棉花筛选获得1个能高效敲除GhAGL16的sgRNA,为定向创制棉花agl16突变体提供了理想的sgRNA。

玉米矮秆突变体20F421的表型鉴定及遗传分析

矮秆资源是农作物矮化育种的物质基础,发掘矮秆基因资源对培育矮秆新品种具有重要作用。为了明确^(252)CF裂变快中子辐射诱变玉米自交系KWS49筛选得到的矮秆突变体20F421的遗传特性和矮化机理,以20F421为材料分别与玉米自交系PH6WC、B73、Mo17及KWS49杂交构建F_(1)和F_(2)分离群体,分析矮秆性状的遗传模式,并以(20F421/B73)F_(2)为定位群体,采用混池转录组测序(bulked segregant RNA-seq,BSR-seq)方法初步定位突变基因。结果表明,与KWS49相比,20F421的植株高度为95.2 cm,降低47.89%;穗位高度为23.9 cm,降低64.54%;茎秆节间长度显著缩短、叶片较直立密生,自交结实良好。遗传分析表明,F2分离群体野生型(高秆)与突变型(矮秆)植株性状分离比例符合3∶1,表明该突变体受单个核隐性基因控制;BSR-seq结果将突变基因定位在1号染色体177~255 Mb之间。通过与B73参考基因组进行比对发现,该区间内含有矮秆基因Br2,将20F421与br2突变体杂交进行等位性检测,F_(1)和F_(2)的株高均没有发生性状分离,表现为突变体20F421和br2表型,推测20F421的矮秆突变基因为矮秆基因Br2的等位突变。研究结果为进一步精细定位、克隆突变基因奠定基础,也为解析玉米矮化机理和培育矮秆玉米新品种提供重要基因资源和理论支撑。

抗枯萎病宝岛蕉早花突变体的筛选与鉴定

【目的】筛选鉴定抗枯萎病香蕉品种宝岛蕉的早花突变体,为进一步利用突变体株系选育适应性更广的香蕉新品种提供参考依据。【方法】利用多代组织培养繁育结合田间种植对比试验,依据生育期短、抗病性强、株高矮、株产高和遗传稳定筛选目标,从宝岛蕉早花突变后代中筛选优良株系,以宝岛蕉为对照,按照香蕉种质资源描述规范对优良突变株系的形态特征和生物学特性等进行观察鉴定,测定分析植株球茎生长点部位碳、氮营养累积以及成花相关激素吲哚乙酸(IAA)、玉米素(ZR)、赤霉素(GA)和脱落酸(ABA)含量差异,通过ISSR分子标记检测突变体及其野生型之间的遗传变异和亲缘关系。以宝岛蕉和主栽品种(桂蕉6号及巴西蕉)为对照,利用伤根浸菌法进行苗期抗病性鉴定,并在广西和海南开展区域种植试验及田间抗病性鉴定。【结果】筛选获得优良突变株系0523(简称0523),其新植蕉平均株高280.0 cm,假茎基围80.5 cm、中围60.0 cm,较宝岛蕉分别减小14.0%、5.8%和11.8%,新抽总叶片数26~29片;果实营养品质和单株产量与宝岛蕉无显著差异(P>0.05,下同)。0523球茎生长点碳氮比较宝岛蕉显著提高19.0%(P<0.05,下同),GA和IAA含量显著降低24.8%和22.6%,ABA和ZR含量与宝岛蕉相比略有增加,差异不显著。抗病性苗期鉴定结果显示0523为中抗且偏强,抗性水平与宝岛蕉相比略有提高,桂蕉6号为高感。突变株系0523与宝岛蕉的多态性比率为8.8%,遗传相似系数为0.95,二者存在差异。0523在广西和海南各试验点第1、2造蕉平均发病率分别为4.5%和3.5%,较主栽品种降低87.8%和94.1%,各试验点发病率均显著低于主栽品种。0523第1、2造蕉的生育期较宝岛蕉显著缩短,与主栽品种无显著差异。【结论】突变株系0523具有抗枯萎病、早熟、矮化、适应性广等优良性状,可用来培育大面积推广的香蕉新品种,或作为亲本育种材料应用于香蕉育种研究。

代谢组与转录组联合解析赤皮青冈叶片黄化变异机制

为揭示赤皮青冈叶色黄化变异机制,该研究以赤皮青冈叶色变异植株和正常植株的叶片为试验材料,采用超高效液相色谱串联质谱法和高通量RNA测序技术分别进行代谢组和转录组分析。结果表明:(1)代谢组在正离子(POS)、负离子(NEG)模式下分别检测出正常植株和突变体之间存在257个和357个显著差异代谢物(SCMs),其中槲皮素、白矢车菊素、杨梅素等多种黄酮类化合物及其糖苷衍生物(吡喃酮啡肽A、异鼠李素3-葡糖苷酸等)在突变体中显著上调,而叶绿素a、叶绿素b、类胡萝卜素等色素含量则显著下降。(2)转录组测序检测出4146个差异表达基因(DEGs),其中1711个基因上调表达,2435个基因下调表达。(3)KEGG富集分析表明,SCMs和DEGs显著富集到光合作用、卟啉与叶绿素代谢、类黄酮生物合成等途径。综上表明,突变体叶色黄化可能是受到叶绿素合成受阻、叶绿体发育异常及黄酮物质合成增加等因素的综合影响。此外,MYB和bHLH家族基因在突变体中显著上调,证实该两类转录因子参与调控类黄酮生物合成。该研究结果为植物黄化突变的分子机制研究提供了新的见解,也为叶色功能基因挖掘与园林植物育种工作提供了参考。

大白菜蜡质缺失突变体YW71的遗传及序列变异分析

以大白菜蜡质突变体YW71为对象,研究其亮绿无蜡粉性状的遗传规律和调控基因。通过遗传分析,表明YW71中的亮绿无蜡粉性状由隐性单基因控制。通过等位基因互补实验证明YW71的亮绿性状是BrWAX2等位突变引起的。序列分析表明,在YW71中BrWAX2基因在第3个外显子末端发生了39 bp的缺失,进而引起转录水平的可变剪切和翻译水平的提前终止。表达模式分析表明,BrWAX2基因在YW71茎和叶中表达量显著下降。此外,研究针对39 bp的变异开发并验证了共显性标记BrWAX2-In Del1。研究结果丰富了白菜类蔬菜蜡质突变遗传资源,将为亮绿无蜡粉品种的分子育种提供理论指导和技术支持。