Genetic Analysis and Preliminary Mapping of a Highly Male-Sterile Gene in Foxtail Millet(Setaria italica L.Beauv.) Using SSR Markers

Breeding of male-sterile lines has become the mainstream for the heterosis utilization in foxtail millet,but the genetic basis of most male-sterile lines used for the hybrid is still an area to be elucidated.In this study,a highly male-sterile line Gao146A was investigated.Genetic analysis indicated that the highly male-sterile phenotype was controlled by a single recessive gene a single recessive gene.Using F 2 population derived from cross Gao146A/K103,one gene controlling the highly male- sterility,tentatively named as ms1,which linked to SSR marker b234 with genetic distance of 16.7 cM,was mapped on the chromosome VI.These results not only laid the foundation for fine mapping of this highly male-sterile gene,but also helped to accelerate the improvement of highly male-sterile lines by using molecular marker assisted breeding method.

The NAC-like transcription factor Si NAC110 in foxtail millet(Setaria italica L.) confers tolerance to drought and high salt stress through an ABA independent signaling pathway

Foxtail millet（Setaria italica（L.）P.Beauv）is a naturally stress tolerant crop.Compared to other gramineous crops,it has relatively stronger drought and lower nutrition stress tolerance traits.To date,the scope of functional genomics research in foxtail millet（S.italic L.）has been quite limited.NAC（NAM,ATAF1/2 and CUC2）-like transcription factors are known to be involved in various biological processes,including abiotic stress responses.In our previous foxtail millet（S.italic L.）RNA seq analysis,we found that the expression of a NAC-like transcription factor,SiNAC110,could be induced by drought stress;additionally,other references have reported that SiNAC110 expression could be induced by abiotic stress.So,we here selected SiNAC110 for further characterization and functional analysis.First,the predicted SiNAC110 protein encoded indicated SiNAC110 has a conserved NAM（no apical meristem）domain between the 11–139 amino acid positions.Phylogenetic analysis then indicated that SiNAC110 belongs to subfamily III of the NAC gene family.Subcellular localization analysis revealed that the SiNAC110-GFP fusion protein was localized to the nucleus in Arabidopsis protoplasts.Gene expression profiling analysis indicated that expression of SiNAC110 was induced by dehydration,high salinity and other abiotic stresses.Gene functional analysis using SiNAC110 overexpressed Arabidopsis plants indicated that,under drought and high salt stress conditions,the seed germination rate,root length,root surface area,fresh weight,and dry weight of the SiNAC110 overexpressed lines were significantly higher than the wild type（WT）,suggesting that the SiNAC110 overexpressed lines had enhanced tolerance to drought and high salt stresses.However,overexpression of SiN AC110 did not affect the sensitivity of SiNAC110 overexpressed lines to abscisic acid（ABA）treatment.Expression analysis of genes involved in proline synthesis,Na＋/K＋transport,drought responses,and aqueous transport proteins were higher in the SiNAC110overexpressed lines than in the WT,whereas expression of ABA-dependent pathway genes did not change.These results indicated that overexpression of SiNAC110 conferred tolerance to drought and high salt stresses,likely through influencing the regulation of proline biosynthesis,ion homeostasis and osmotic balance.Therefore,SiNAC110 appears to function in the ABA-independent abiotic stress response pathway in plants.

Identification of no pollen 1 provides a candidate gene for heterosis utilization in foxtail millet(Setaria italica L.)

Male sterility is a common biological phenomenon in plant kingdom and has been used to generate male-sterile lines, which are important genetic resources for commercial hybrid seed production. Although increasing numbers of male-sterility genes have been identified in rice(Oryza sativa) and Arabidopsis(Arabidopsis thaliana), few male-sterility-related genes have been characterized in foxtail millet(Setaria italica). In this study, we isolated a male-sterile ethyl methanesulfonate-generated mutant in foxtail millet, no pollen 1(sinp1), which displayed abnormal Ubisch bodies, defective pollen exine and complete male sterility. Using bulk segregation analysis, we cloned SiNP1 and confirmed its function with CRISPR/Cas9 genome editing. SiNP1 encoded a putative glucose-methanol-choline oxidoreductase.Subcellular localization showed that the SiNP1 protein was preferentially localized to the endoplasmic reticulum and was predominantly expressed in panicle. Transcriptome analysis revealed that many genes were differentially expressed in the sinp1 mutant, some of which encoded proteins putatively involved in carbohydrate metabolism, fatty acid biosynthesis, and lipid transport and metabolism, which were closely associated with pollen wall development. Metabolome analysis revealed the disturbance of flavonoids metabolism and fatty acid biosynthesis in the mutant. In conclusion, identification of SiNP1 provides a candidate male-sterility gene for heterosis utilization in foxtail millet and gives further insight into the mechanism of pollen reproduction in plants.

Genetic Diversity and Classification of Chinese Elite Foxtail Millet [Setaria italica (L.) P. Beauv.] Revealed by Acid-PAGE Prolamin

Arid and semi-arid regions of China account for more than half of the country. Because of drought resistance and high nutritive value, elite foxtail millet (Setaria Italica (L.) P. Beauv.) is one of the most important cereal crops in China. Evaluation of germplasm and genetic diversity of foxtail millet is still in its infancy, but prolamin could play an important role as a protein marker. To investigate the genetic diversity and population structure of foxtail millet from different ecological zones of China, 90 accessions of foxtail millet were collected from three major ecological areas: North, Northwest, and Northeast China. The prolamin contents were examined by acid polyacrylamide gel electrophoresis (acid-PAGE). Five to twenty-two prolamin bands appeared in tested varieties, of which were polymorphic, so prolamin patterns of foxtail millet varieties can be used in variety identification and evaluation. Structure analysis identified six groups, which matches their pedigree information but not their geographic origins. This indicated a high degree (87.78%) of consistency with a phylogenetic classification based on SSR. The results showed prolamin banding patterns were an effective method for analyzing foxtail millet genetic variability.

Retrotransposon-mediated DELLA transcriptional reprograming underlies semi-dominant dwarfism in foxtail millet

Retrotransposons account for a large proportion of the genome and genomic variation, and play key roles in creating novel genes and diversifying the genome in many eukaryotic species. Although retrotransposons are abundant in plants, their roles had been underestimated because of a lack of research. Here, we characterized a gibberellin Acid (GA)-insensitive dwarf mutant, 84133, in foxtail millet. Map-based cloning revealed a 5.5-kb Copia-like retrotransposon insertion in DWARF1 (D1), which encodes a DELLA protein. Transcriptional analysis showed that the Copia retrotransposon mediated the transcriptional reprogramming of D1 leading to a novel N-terminal-deleted truncated DELLA transcript that was putatively driven by Copia's LTR, namely D1-TT, and another chimeric transcript. The presence of D1-TT was confirmed by protein immunodetection analysis. Furthermore, D1-TT protein was resistant to GA3 treatment compared with the intact DELLA protein due to its inability to interact with the GA receptor, SiGID1. Overexpression of D1-TT in foxtail millet resulted in dwarf plants, confirming that it determines the dwarfism of 84133. Thus, our study documents a rare instance of long terminal repeat (LTR) retrotransposon-mediated transcriptional reprograming in the plant kingdom. These results shed light on the function of LTR retrotransposons in generating new gene functions and genetic diversity.

Assessment of Genetic Relationship of Foxtail Millet with Its Wild Ancestor and Close Relatives by ISSR Markers

Inter simple sequence repeat（ISSR） analysis was applied to samples of foxtail millet and its wild ancestor and other close relatives of the genus Setaria in order to detect domestication-related geographical structure and phylogenetic relationship of those species.Eighty-one accessions of nine Setaria species that originated from different regions were used in this study.Fourteen out of the 27 ISSR primers screened amplified successfully and a total of 156 markers were scored for all the accessions,with a high level of polymorphism being detected.The dendrogram based on UPGMA cluster analysis showed clear geographic structure among foxtail millet and its wild ancestor green foxtail,which implies that northern China is the domestication center for both the Chinese and European foxtail millet landraces used in this study.This result did not support the hypothesis that China and Europe are independent domestication centers for foxtail millet proposed by several previous studies based on morphological and isozyme data.The dendrogram also clearly classified the Setaria sample used into two groups,a viridis and a pumila groups.The viridis group was composed of S.viridis,S.italica,S.faberii,S.verticillata,S.leucopila,and S.queenslandica,and the pumila group consisted of S.parviflora and S.pumila,which is consistent with the recently proposed hypothesis of multiple origin of Setaria species.The phylogenetic relationships among different species are discussed.

A nucleotide substitution at the 5′ splice site of intron 1 of rice HEADING DATE 1(HD1) gene homolog in foxtail millet, broadly found in landraces from Europe and Asia

We investigated genetic variation of a rice HEADING DATE 1(HD1) homolog in foxtail millet.First, we searched for a rice HD1 homolog in a foxtail millet genome sequence and designed primers to amplify the entire coding sequence of the gene. We compared full HD1 gene sequences of 11 accessions(including Yugu 1, a Chinese cultivar used for genome sequencing) from various regions in Europe and Asia, found a nucleotide substitution at a putative splice site of intron 1, and designated the accessions with the nucleotide substitution as carrying a splicing variant. We verified by RT-PCR that this single nucleotide substitution causes aberrant splicing of intron 1. We investigated the geographical distribution of the splicing variant in 480 accessions of foxtail millet from various regions of Europe and Asia and part of Africa by d CAPS and found that the splicing variant is broadly distributed in Europe and Asia. Differences of heading times between accessions with wild type allele of the HD1 gene and those with the splicing variant allele were unclear. We also investigated variation in 13 accessions of ssp. viridis, the wild ancestor, and the results suggested that the wild type is predominant in the wild ancestor.

Plants regeneration from protoplast and their genetic variation in foxtail millet

Compact calli derived from immature spikelet of a foxtail millet variety—Jigu 11cann’t be directly used for protoplast isolation because of its firm physical structure,and must beloosened with subculturing in M1,M2 and M3 media successively and altering these media compo-sitions.The loosened calli can be selected from the regulation and used for protoplast isolationsuccessfully.Rate of protoplast division in KM8P medium was 12.3—33.5%.Calli derivedthrough protoplast division are loose and cann’t be used directly for plan regeneration because ofits soft physical structure.When they were subcultured in N6—1,N6—2,N6—3 and N6—4 media,in which the media compositions were changed,the compact calli were obtained and 129 plantletswere regenerated from them.101 plants,which grew to maturity after transplanting the plantletsinto field,exhibited sterility in some degree.Most of the subsequent lines derived from the regen-erated plants were sterile and only two lines could get normal reproduction.

Genetics, Development, and Application of Cytoplasmic Herbicide Resistance in Foxtail Millet

The effect of cytoplasmic herbicide resistant gene in millet plants was studied. The heterozygous populations and isogenic lines with homocaryotic alloplasmic genes were obtained by crossing and reciprocal crossing of cytoplasmic herbicide resistant plants with susceptive plants of foxtail millet. The characters of F1, F2, backcross and composite cross groups, and the growth and development of isogenic lines were compared. The cytoplasmic herbicide resistant gene slowed the development of seedling, delayed heading, and shortened the milking stage in the foxtail millet plant. Yield capacity and main agronomic characters were all affected by the cytoplasmic herbicide resistant gene in most of the backcross, composite cross, and F2 populations. However, there was stronger hybrid vigor in F1. The backcrosses, composite crosses, and F2 populations were widely separated and some of them had good characters similar to those of susceptive groups. The plant characters and development of foxtail millet were negatively affected by the cytoplasmic herbicide resistant gene. The authors proposed a method of using hybrid vigor to obtain high yield and avoid the negative effects of herbicide resistance cytoplasm in plant growth. The expected results could be obtained by selecting individuals in separate populations of fast developed seedlings, well-developed roots, and with capacities of early heading and fast milking. Guided by the principal mentioned above, many high yield lines and hybrid crosses of foxtail millet with herbicide resistant cytoplasm were obtained.

The boron transporter SiBOR1 functions in cell wall integrity, cellular homeostasis, and panicle development in foxtail millet

Boron(B) is an essential micronutrient for vascular plant growth. Both B deficiency and toxicity can impair tissue development in diverse plant species, but little is known about the effect of B on reproductive panicle development and grain yield. In this study, a mutant of Setaria italica exhibiting necrotic panicle apices was identified and designated as sibor1. Sequencing revealed a candidate gene, Si BOR1, with a G-to-A alteration at the seventh exon. Knockout transgenic lines generated by clustered regularly interspaced short palindromic repeats and their associated protein-9 also had necrotic panicles, verifying the function of Si BOR1. Si BOR1 encoded a membrane-localized B efflux transporter, co-orthologous to the rice BOR1 protein. Si BOR1 was dominantly expressed in panicles and displayed a distinct expression pattern from those of its orthologs in other species. The induced mutation in Si BOR1 caused a reduction in the B content of panicle primary branches, and B deficiency-associated phenotypes such as thicker cell walls and higher cell porosity compared with Yugu 1. Transcriptome analysis indicated that differentially expressed genes involved in cell wall biogenesis, jasmonic acid synthesis, and programmed cell death response pathways were enriched in sibor1. q PCR analysis identified several key genes, including phenylalanine ammonia-lyase(Si PAL) and jasmonate-ZIM-domain(Si JAZ) genes, responsive to B-deficient conditions. These results indicate that Si BOR1 helps to regulate panicle primary branch development to maintain grain yield in S. italica. Our findings shed light on molecular mechanisms underlying the relationship between B transport and plant development in S. italica.

施氮量对谷子产量、氮素利用及小米品质的影响

【目的】明确不同施氮量下谷子产量、干物质分配和氮素累积转运特征,分析氮用量对小米糊化特性和有益微量元素含量的影响及其与植株氮素累积的关系,探究植株氮素营养对小米品质的影响。【方法】于2020—2021年在山西省沁县研究4个施氮水平(0、75、120和150 kg·hm^(-2))对春播谷子产量、氮素吸收与利用特征及小米品质的影响。【结果】施氮提高谷子收获穗数、穗粒数和植株的干物质生产能力,增加了氮素由营养器官向籽粒的转运率,促进了干物质及氮素向籽粒的分配,从而提高产量。施氮也提高了小米中铁、锌、钙、镁和硒的含量,其中,施氮75 kg·hm^(-2)时上述元素含量的增幅最大,氮利用率最高。与不施氮相比,施氮75 kg·hm^(-2)时谷子收获穗数、穗粒数、产量、地上部生物量、收获指数、氮素累积总量和氮素转运率增幅最高,增幅分别可达7.5%、23.3%、31.0%、21.2%、8.6%、40.3%和9.2%,小米中铁、锌、钙、镁和硒含量的增幅分别为37.2%、43.6%、56.0%、30.5%和16.9%。过量施氮(150 kg·hm^(-2))不利于谷子穗粒数和收获指数的提高及氮素由营养器官向籽粒的转运,与施氮量75 kg·hm^(-2)比较,两年氮素转运率分别降低了23.1%和28.2%;氮素施用过量也降低了小米支链淀粉含量,淀粉形成受限,抑制了小米粉最终黏度、回升值和峰谷黏度,影响糊化品质,同时氮肥利用率低至25%左右。谷子地上部氮吸收量与小米中铁、锌、钙、镁和硒含量呈极显著的正相关,但与小米中支链淀粉含量、小米粉的最终黏度和峰谷黏度呈显著的负相关。【结论】施氮量在75—120kg·hm^(-2),能促进谷子干物质及氮素向籽粒的分配,实现籽粒产量、小米糊化品质和有益微量元素含量的同步提升。

谷子MAPK家族成员的鉴定及其对生物胁迫的响应分析

MAPK在植物的生长发育调节、生物和非生物胁迫反应、激素信号转导中具有重要作用。系统分析谷子SiMPKs基因家族成员全基因组分布、结构、进化及其响应不同胁迫的表达特性,对于阐明其生物学功能具有重要意义。本研究利用谷子和水稻MAPK蛋白保守结构域及特异TXY基序的氨基酸序列在全基因组水平鉴定了谷子SiMPKs家族成员,分析其蛋白质理化性质、系统进化、染色体定位、基因结构、蛋白质保守基序、启动子顺式作用元件及共线性等。利用荧光定量PCR技术,分析了谷子SiMPKs在不同组织部位和谷锈菌、玉米螟病虫害生物胁迫以及不同激素处理下的表达模式。结果显示,共鉴定到15个谷子SiMPK成员,其编码的蛋白质含有220~611个氨基酸,相对分子量范围25.77~69.63 kD,等电点范围5.46~9.34。系统进化分析表明,SiMPK基因分为4组,A、B、C组包含TEY基序,D组包含TDY基序。SiMPK基因分布在1号、3号、4号、5号、8号和9号染色体上,含有3~11个外显子,所有SiMPK蛋白均含有motif 1与motif 2。上游2000 bp启动子区域预测到多个与胁迫、激素和植物生长发育等相关的顺式作用元件。qRT-PCR结果表明,大部分基因具有明显的组织表达特异性;除SiMPK21-2和SiMPK6外,其余成员对谷锈菌侵染、玉米螟取食、SA和MeJA激素处理等1~3种胁迫具有明显响应。以上结果为进一步研究SiMPK基因在谷子应对病虫害生物胁迫中的功能奠定了理论基础。

谷子毛状根诱导方法的建立与优化

为建立一种快速鉴定谷子基因功能的技术体系,本研究通过比较谷子外植体、品种、乙酰丁香酮、菌液浓度和共培养时间对发根农杆菌K599介导的毛状根诱导效率的影响,发现发根农杆菌浓度在OD600为0.5、以谷子芽尖为外植体、在含有100μmol L–1乙酰丁香酮的毛状根诱导培养基上共培养3 d时,可使毛状根诱导率高达80.24%。将GFP基因进行毛状根遗传转化,通过GFP基因的PCR扩增和GFP荧光观察结果分析,发现谷子毛状根的转基因效率大于70%。利用该体系对谷子SiDVL1和SiDVL3的亚细胞定位和SiNHX2、SiCBL4和SiCBL7基因功能进行了分析和鉴定。结果表明SiDVL1和SiDVL3在谷子毛状根中的亚细胞定位与在烟草叶片中的一致;SiNHX2、SiCBL4和SiCBL7转基因谷子的存活率显著高于空载体转化谷子。说明本研究建立了一种高效快速鉴定谷子基因定位和功能的方法。

谷子AP基因家族鉴定及其对非生物胁迫的响应分析

天冬氨酸蛋白酶(AP)是一类重要的水解酶,在植物生长发育及抵御生物和非生物胁迫方面发挥着重要作用。谷子(Setaria italica)作为禾本科C4植物抗逆研究的模式作物,目前关于天冬氨酸蛋白酶家族基因功能的研究较少。为深入探究AP基因家族在谷子中的功能作用,本研究基于AP保守Pfam序列全基因组筛选鉴定谷子AP基因家族的成员,并通过生物信息学方法对其理化性质、亚细胞定位、基因结构、保守结构域、系统进化发育、启动子顺式作用元件及共线性等分析,同时利用荧光定量PCR技术对其在非生物胁迫下的表达模式进行了研究。结果表明,谷子基因组中共有AP基因家族成员58个;系统进化树显示该基因家族可分为5个亚家族,其中Group B编码非典型天冬氨酸蛋白酶,其他亚家族编码类nucellin天冬氨酸蛋白酶;基因结构和保守基序分析表明,谷子AP家族同一亚家族成员具有较高的保守性;共线性分析结果显示,谷子AP基因家族与水稻(Oryza sativa)和玉米(Zea mays)AP基因家族成员之间存在大量的同源基因对;启动子顺式作用元件分析表明,SiAPs基因家族中大部分成员含有与非生物胁迫和生物激素响应相关的顺式元件,如响应干旱和低温胁迫的顺式作用元件、水杨酸有关的应答元件等。进一步RT-q PCR结果发现,SiAPs基因家族成员在谷子根、茎、叶、穗中差异表达;在低温胁迫下,SiAP3、SiAP9、SiAP48基因表达量显著升高;在干旱胁迫和水杨酸处理下,部分基因表达的变化趋势基本一致。SiAPs对谷子响应非生物胁迫起重要的调控作用,本研究结果可为SiAPs的抗逆功能分析提供参考。

谷子全生育期抗旱性鉴定及抗旱指标筛选

作物全生育期抗旱性对发掘和利用抗旱品种和抗旱基因至关重要,但谷子全生育期抗旱鉴定至今未有报道,抗旱鉴定缺乏鉴定指标。本试验在干旱池模拟干旱条件下,对苗期抗旱性表现不同的谷子品种进行了全生育期抗旱性研究,调查分析了根干重等形态和生理性状在干旱胁迫条件下的变化;采用相关和灰色关联度等方法,分析这些指标与抗旱性(DRI)的关系。结果表明,相对根冠比、相对单穗粒重和灌浆期光合速率、蒸腾速率同抗旱性表现极显著相关,可以作为谷子全生育期抗旱性鉴定的指标;而相对根干重、相对单穗重、相对株高和气孔导度则可以作为谷子全生育期抗旱性鉴定的参考指标;在供试的品种中,红根谷和大齐头白表现了良好的综合抗旱性。本文还讨论了抗旱性的复杂性以及不同性状对干旱胁迫的反应,所建立的指标对谷子全生育期抗旱鉴定具有指导意义。

谷瘟病菌生理小种鉴别及谷子标准品种体系的构建

【目的】谷瘟病是谷子生产中的重要病害,确定谷瘟病菌不同生理小种对谷子抗病资源鉴定、抗病品种培育和生产上不同抗病品种的合理配置有重要意义。构建谷瘟病小种鉴别的谷子品种体系,为鉴别不同谷瘟病生理小种奠定基础。【方法】用采集自不同谷子产区的10份谷瘟病菌对苗期谷子核心种质资源的60份代表品种进行接种鉴定,分别对不同菌株进行致病性和谷子品种抗、感敏感性判定,按照谷子谷瘟病0—9级法划分标准进行划分,将不同的抗性结果分别记录为高抗、抗病、中抗、感病和高感5个抗病水平,其中,高抗、抗病和中抗记作0,感病和高感记作1,将抗感性结果转化为0/1数据,用NTSYS软件构建进化树,根据品种的抗感性分类,选择最少的品种数量构建谷瘟病小种鉴定的标准品种体系。【结果】根据谷子资源对接种病菌的抗感反应差异,用NTSYS软件开展谷瘟病菌致病性聚类分析,以相似系数0.70为界,将10个谷瘟病菌株分为3类,将供试品种对10个谷瘟病菌株的抗感反应数据同样用NTSYS软件进行聚类分析,以相似系数0.65为界,将谷子品种资源划分为5类,并筛选出单皮粘、金屏谷子、锦谷5号、大毛毛谷、龙爪谷、假金苗和牛头谷等7个品种作为谷瘟病小种鉴别品种体系。同时筛选出黄棒头、齐头黄、单皮粘、白谷、维子那谷和郑谷4号等6个抗广谱菌株的品种,可以作为谷子抗病育种的抗性基因来源。【结论】建立了一套谷瘟病生理小种鉴别的品种体系,并为谷子抗谷瘟病育种筛选出多份广谱抗性基础材料。

油菜素内酯对阔世玛胁迫下谷子叶片光合荧光特性及糖代谢的影响

【目的】探明油菜素内酯(brassinolide,BR)对阔世玛胁迫下谷子叶片的光合荧光特性及糖代谢的影响,为谷子田磺酰脲类除草剂阔世玛的安全应用及利用植物生长调节剂油菜素内酯缓解除草剂药害提供理论基础和技术途径。【方法】采用完全随机设计,重复3次,以杂交高产谷张杂5号和普通优质谷晋谷21号为材料,进行盆栽试验,待幼苗长至3—5叶期时,喷施7.5 mg·L^(-1)阔世玛,药后1 d,分别叶面喷施清水(对照)、0.05、0.1、0.2和0.4 mg·L^(-1)的油菜素内酯,7 d后对所有处理的谷子幼苗株高、叶面积、鲜重等农艺性状、叶片光合色素含量、气体交换参数、叶绿素荧光参数、糖含量及蔗糖代谢关键酶活性进行测定与分析。【结果】在7.5 mg·L^(-1)阔世玛胁迫下,谷子的株高、叶面积、鲜重、叶绿素a、叶绿素b、类胡萝卜素、叶绿素(a+b)、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、最大光化学产量(Fv/Fm)、表观光合电子传递速率(ETR)、非调节性能量耗散量子产量(Y(NO))、中性转化酶(NI)、蔗糖合成酶(SS)及蔗糖磷酸合成酶(SPS)活性显著降低;而胞间CO2浓度(Ci)、调节性能量耗散量子产量(Y(NPQ))、还原性糖、蔗糖和淀粉含量显著升高。药后1 d喷施适宜浓度的BR能部分缓解阔世玛对谷子的药害,显著提高谷子的株高、叶面积、鲜重、光合色素含量、Pn、Tr、Gs、Fv/Fm、ETR、Y(NO)、NI、SS及SPS活性,并显著降低Ci、Y(NPQ)、还原性糖、蔗糖和淀粉含量;其中,0.05—0.1 mg·L^(-1) BR对缓解张杂5号阔世玛药害的效果较好,0.1—0.2 mg·L^(-1) BR对缓解晋谷21号阔世玛药害的效果较好。≥0.4 mg·L^(-1) BR不能缓解阔世玛药害。【结论】7.5 mg·L^(-1)的阔世玛对谷子产生显著药害的原因之一是降低了其光合色素含量,抑制了PSⅡ光化学活性,影响了糖代谢的正常运转。0.1 mg·L^(-1)的油菜素内酯通过提高光合色素含量、增加气孔导度、提高PSⅡ光化学活性、促进碳水化合物的卸出、维持蔗糖代谢平衡等来缓解阔世玛对谷子光合作用的抑制。

细胞质抗除草剂谷子遗传发育特点及应用研究

目的研究细胞质抗除草剂基因对谷子性状和发育的影响。方法利用细胞质抗除草剂谷子与敏感型谷子正反交和多代回交等方法,获得了同核异质杂交群体和近等基因系,比较其F1、F2、回交和复合杂交世代的群体差异和近等基因系的生长发育差异。结果具有抗除草剂细胞质的谷子苗期发育迟缓、抽穗晚,灌浆时间短;用其杂交获得的回交、复合杂交及F2的多数群体表现了生长弱势。但是具有细胞质除草剂抗性的谷子,在杂交F1代可产生较大的杂种优势;回交、复合交和F2代有较大的分离,并且个别组合表现了与敏感细胞质一样的丰产性。结论细胞质抗除草剂基因对谷子的生长和性状发育有影响,但利用杂交种可避免细胞质抗性产生的不利影响,获得丰产性;对抗性杂交群体和个体进行选择可达到预期效果。在对抗除草剂谷子选育时,应注重苗期发育快、根系发达、抽穗早、灌浆速度快的单株。把以上的研究结果应用于实践,获得了多个细胞质抗除草剂谷子的丰产杂交组合和品系。

外源铅、铜胁迫对不同基因型谷子幼苗生理生态特性的影响

采用盆栽土培法,研究了4种基因型谷子幼苗对Pb2+、Cu2+胁迫的生长响应、DNA损伤及吸收积累、迁移特性。结果表明,D2-8、安06、黄米和朝谷幼苗对Pb2+、Cu2+的平均耐性指数分别为0.87、0.81、0.78、0.71和0.96、0.97、0.79、0.74。在400 mg/kg Pb2+、Cu2+浓度下,4种谷子幼苗叶绿素a、b总量分别为对照的33.3%、52.6%、37.5%、49.4%和113.5%、72.3%、51.9%、75.6%,而叶绿素a/b值均高于对照。Pb2+胁迫下4种谷子幼苗中可溶性蛋白质和DNA含量随浓度升高逐渐下降,Cu2+处理组则表现为低浓度(≤100 mg/kg)的促进和高浓度(≥200 mg/kg)的抑制效应。4种谷子幼苗的DNA增色效应值在Pb2+、Cu2+胁迫下均表现为先上升后下降的趋势,其中Pb2+对朝谷和D2-8的增色效应影响较大,而Cu2+对朝谷和安06的影响最为明显。D2-8和朝谷对Pb2+、Cu2+的吸收富集能力高于安06和黄米,D2-8和安06对Pb2+、Cu2+的转运能力大于朝谷和黄米。总体来看,Pb2+对谷子幼苗的生理生态影响和遗传毒害效应大于Cu2+,4种基因型谷子对Pb2+胁迫的耐性顺序为安06>D2-8>黄米>朝谷,对Cu2+的耐性顺序为D2-8>安06>朝谷>黄米。

铅胁迫对不同基因型谷子幼苗生理特性及基因组DNA多态性的影响

以4种基因型谷子为供试材料,采用盆栽土培法,研究了土壤重金属Pb2+胁迫对谷子幼苗基因组DNA多态性和可溶性糖、脯氨酸、丙二醛(MDA)含量的影响。结果表明:经50～400mg·kg-1Pb2+处理30d后,4种谷子幼苗体内可溶性糖含量随Pb2+浓度上升而逐渐降低,降幅为对照的31.45%～49.11%。脯氨酸含量则表现为低浓度(≤100mg·kg-1)的促进和高浓度(≥200mg·kg-1)的抑制效应,MDA含量均有增加且与对照差异显著。Pb2+胁迫下不同基因型谷子幼苗基因组DNA的RAPD图谱发生明显变化,表现为单条或多条RAPD谱带的缺失、增加及荧光强度的增强或减弱,表明Pb2+明显影响谷子幼苗细胞中基因组模板DNA的稳定性,DNA多态性变化与Pb2+浓度之间存在剂量-效应关系。不同基因型谷子对Pb2+胁迫的生理和遗传损伤响应存在差异。利用RAPD技术获得的DNA多态性变化可作为检测Pb2+遗传毒性效应的生物标记物。