花生苗期干旱处理后转录和代谢通路分析

为解析花生耐旱性的调控基础,本研究通过对10个不同的花生材料苗期进行干旱-复水实验,结合转录组分析,探讨了干旱条件下不同花生材料抵御干旱胁迫的分子机制。研究结果显示,来源于非洲的花生材料Waliyar Tiga耐旱性最强,其次是kQ044抗青、中花16和早花生,干旱敏感的材料为狮头企、山花13、ICGV86745以及丰花2号;耐旱及干旱敏感材料的根冠比存在显著差异,耐旱材料的根冠比平均值为35.0%,干旱敏感材料的根冠比平均值为15.26%。早花生和中花16的根冠比最大。转录组结果表明抗感材料的差异表达基因主要富集在氧化磷酸化、光合作用和植物代谢途径;通过差异基因富集分析发现,耐旱材料在干旱条件下生长素应答途径基因的表达明显弱于敏感材料。生理和转录组的结果表明耐旱材料利用发达的根系系统、能量代谢的提升、次生代谢的加强和生长的抑制四个方面共同应对干旱胁迫。抗旱材料中花16和Waliyar Tiga在干旱条件下均具有较强的光合作用和氧化磷酸化的能力,中花16的根冠比显著大于Waliyar Tiga,但其耐旱性不及Waliyar Tiga,推测可能源于其较大的叶面积导致更多的叶面水分散失,从而使其耐旱能力低于Waliyar Tiga。     

Physiological and anatomical changes in two rapeseed (Brassica napus L.) genotypes under drought stress conditions

Understanding the mechanisms of drought resistance in crop species is crucial for the selection and breeding of tolerant rapeseed (Brassica napus L.) varieties. The present study aimed to assess the physiological and anatomical responses of two rapeseed genotypes, P287 (drought-tolerant) and T88 (drought-sensitive) under three intensities of drought stress. All physiological and anatomical parameters related to drought acclimation were significantly altered in both genotypes under stress conditions. At the fourth-leaf stage, the relative water content, chlorophyll content, protein content, malondialdehyde content, and the activities of peroxidase and catalase in P287 were significantly higher than those in T88, particularly under severe drought conditions. After rehydration, all physiological indexes recovered rapidly, especially in P287. In addition, under drought stress, compared with T88, P287 had thicker palisade tissue, thinner spongy tissue, higher ratio of chloroplast length to chloroplast width, higher stomatal density and stomatal closure rate. Overall, the interaction between physiological and anatomical features improved the drought tolerance of P287 under drought stress conditions.     

干旱胁迫对不同类型红花品种（系） 苗期生理生化特性的影响

为筛选抗旱品种提供依据,本试验从14份红花品种中筛选出2个抗旱品种（PI401470和PI401477 ）和2个干旱敏感型品种（系）（PI560169和川红1号）,并以此4份品种（系）为材料,研究干旱胁迫对红花幼苗光合、渗透调节物质和抗氧化物保护酶等生理生化特性的影响。结果表明,干旱胁迫下,4个红花品种（系）叶片净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）和蒸腾速率（Tr）均呈不同程度的下降趋势,且品种间差异显著（P﹤0.05）;抗旱红花品（系）的各光合特性指标降幅均低于敏感型红花品种（系）。干旱胁迫条件下,渗透调节物质可溶性糖、可溶性蛋白质、脯氨酸含量均上升,保护性酶SOD、POD和CAT活性也均呈升高趋势,且抗旱型红花品种（系）的增长率高于敏感型品种（系）;抗旱型品种（系）MDA含量增长率低于敏感型品种。对11项指标进行主成分分析,提取了2个主成分,以净光合速率、气孔导度、胞间CO2 浓度、蒸腾速率、SOD活性和CAT活性为第一主成分,以可溶性蛋白质和脯氨酸为第二主成分的抗旱性鉴定指标,累计贡献率达89.50％。     

Expression pattern of GmLAX genes under different stresses in soybean drought sensitive cultivar and tolerant cultivar

Auxin has been reported to regulate plant growth and development, as well as to mediate plant adaption to abiotic stresses, including drought. AUX/LAX family displays auxin uptake functions and comprises four highly conserved genes AUX1 and LIKE AUX1 (LAX1, LAX2, and LAX3) in Arabidopsis. There are fifteen GmLAX family genes in the soybean genomes and several members were regulated by dehydration stress. In this study, the sequence differences and expression pattern of GmLAXs-I were analyzed under stress treatment between the soybean drought-tolerant Jindou 21 and drought-sensitive varieties Zhongdou 33. Five homologous genes of AUX1 were all responsive to PEG, salt, ABA and IAA stimuli. There were two SNPs in the promoter region of GmLAX4 gene, and this gene was differentially expressed in two cultivars. Moreover, our results showed YFP-GmLAXs are predominantly localized in plasma membrane. Taken together, our results suggest that GmLAXs are involved in abiotic response, which can provide theoretical and technical support for the genetic improvement of soybean drought tolerance.     

A field screening technique for evaluating rice germplasm for drought tolerance during the vegetative stage

A rapid method of testing direct-seeded rainfed rices (Oryza sativa L.) for drought reaction, concurrently with, but separately from, evaluation for agronomic traits and reaction to various stresses, is needed for early identification of desirable genotypes. Thus, a technique which quantifies soil moisture stress for screening thousands of cultivars and breeding lines for drought tolerance during the vegetative stage was developed. Seeds were drilled on dry granular clay soil (Andaqueptic Haplaquoll) in the field, then sprinkler-irrigated every 4 days for 37 days. As the soil dried, each entry was visually scored for drought reaction at 0.1–0.2, 0.4–0.5 and 0.8–1.0 MPa soil moisture tension (smt) at 20-cm soil depth. Entries were visually scored for drought recovery 10 days after the field was reirrigated. A total of 38 691 rices was tested in the dry seasons from 1978 to 1985. The 8-year screening test showed reproducibility of results in the field as indicated by the consistent scores of drought-tolerant and susceptible control cultivars within and across years. Ten germplasm accessions repeatedly performed similar to, or better than, the drought-tolerant control. There were ten outstanding drought-tolerant breeding lines, six of which were progenies of moderately tolerant Nam Sagui 19 from Thailand. The 20 outstanding selections likewise had consistent drought-tolerant scores across years, irrespective of duration of stress, which ranged from 31 to 54 days.     

甘蓝型油菜全基因组DELLA蛋白基因家族的鉴定和表达分析

DELLA蛋白是参与赤霉素调控途径的关键因子,对调节植物的生长发育具有重要的作用。为了揭示甘蓝型油菜中DELLA蛋白家族的分布和特征,利用生物信息分析了家族成员、序列特征、进化关系和组织表达。结果表明,甘蓝型油菜中有13个DELLA蛋白基因,被定位到8条染色体和2条随机序列（chrC09_random和chrCnn_random）上;系统进化树分析发现,该家族被聚为4个亚家族,第一亚家族含有7个基因,第二、三和四亚家族各包括2个基因; DELLA基因呈组织特异性表达,其中BnaA10g17240D、BnaC09g40420D、BnaCnng68300D和BnaC05g47760D在各组织中表达都相对较高,在茎中BnaA06g34810D、BnaA09g18700D和BnaC09g52270D表达最高。本研究为后续基因的功能研究提供参考。     

江淮大豆育种种质苗期耐旱性鉴定

江淮地区是我国大豆重要产区,季节性干旱时有发生,发掘适合本地区种植的耐旱新材料十分必要。选用210份江淮大豆育成新品种(系)及其部分亲本为材料,于2015和2016两年进行旱棚盆栽试验,以地上部干重、株高、主根长和根干重4个性状的耐旱系数为指标,通过主成分分析、隶属函数值法和聚类分析对其苗期耐旱性进行综合评价。结果表明:与正常供水相比,干旱胁迫下4个性状均显著降低,其中地上部干重、根干重、株高和主根长平均分别减小54%、42%、39%和15%;方差分析显示各性状在水分处理间和材料间均存在极显著差异,而株高和根干重性状上基因型、水分处理和年份三因子间一级互作和二级互作效应均为极显著。地上部干重与株高、根干重间以及主根长与根干重间的耐旱系数存在显著正相关,反映指标间有内在联系;主成分分析提取的前3个相互独立的主成分的累积贡献率达83.61%,能较好地替代原有4个信息部分重叠的性状;进一步获得耐旱性综合评价D值,结合聚类分析将所有材料分为强耐旱、耐旱、中度耐旱、干旱敏感、干旱强敏感5类。共鉴定出强耐旱材料5份(包括IA2077、YC4H/NN88-31//NN73-935、蒙8108、NN88-48/NN86-4和NN88-48/D76-1609)、耐旱材料57份。来自淮南和淮北地区的强耐旱或耐旱材料分别为27份(占该地区83份材料的32.53%)和19份(占该地区76份材料的25.00%)。所得结果可为大豆耐旱遗传育种提供材料。     

转AtGA2ox1基因玉米自交系和杂交种的耐旱性分析

AtGA2ox1基因是调控赤霉素代谢的关键基因。以3个AtGA2ox1基因转化体回交转育玉米自交系和配制的杂交组合为研究材料,系统开展玉米自交系和杂交种的耐旱性分析。结果表明,3个转化体在回交转育过程中,多世代间遗传稳定。苗期不同转化体玉米在干旱胁迫24 d后复水仍能正常生长;对照材料胁迫后叶片卷曲至萎蔫,复水后无法恢复生长。通过对丙二醛、超氧化物歧化酶、过氧化氢酶等生理生化指标的跟踪监测发现,干旱胁迫条件下转基因玉米的MDA含量低于对照约20%;超氧化物歧化酶、过氧化氢酶活性高于对照20%,降低玉米细胞膜氧化损伤来增强转基因玉米耐旱胁迫能力,与玉米耐旱表型一致。成熟期干旱条件下,对照玉米果穗变小,穗长变短,穗重减轻。转基因杂交种的粒重和百粒重显著高于对照,其中杂交种NKYGA09*X923-1百粒重高于对照杂交种21.21%,表现出潜在的育种价值。     

甘蓝型油菜CO同源基因功能初步研究

CONSTANS(CO)基因是植物光周期途径中重要的转录调控因子.为了探究甘蓝型油菜CO同源基因的功能,以拟南芥CO基因的CDS序列为参考序列,从甘蓝型油菜品种Westar的cDNA中分离得到CO的两个同源基因(基因编号:BnaC09g41990D和BnaA10g18430D),命名为BnaC09CO和BnaA10CO...     

甘蓝型油菜微核心种质耐旱鉴定与评价指标筛选

干旱是威胁油菜生产的重要非生物逆境，建立有效的耐旱鉴定方法，筛选鉴定耐旱油菜种质资源，对培育油菜耐旱新品种、提高油菜稳产性具有重要意义。本文以107份甘蓝型油菜微核心种质为材料，设置正常供水和干旱2个处理，采用干旱-复水-干旱-复水的处理方法，通过测定旱害指数、叶片萎蔫指数、地上部鲜重胁迫指数、地上部干重胁迫指数、根鲜重胁迫指数、根干重胁迫指数、植株总鲜重胁迫指数、植株总干重胁迫指数等指标，评价油菜种质耐旱性变异，筛选理想的耐旱评价指标。结果表明，干旱严重抑制了甘蓝型油菜的生长，8个评价指标均表现出显著差异，并呈正态分布。地上部鲜重胁迫指数、植株总鲜重胁迫指数和旱害指数3个指标之间显著相关，可作为甘蓝型油菜苗期耐旱性的主要评价指标，其中地上部鲜重胁迫指数最为简便、准确和有效；综合应用这3个评价指标，明确了107份微核心种质耐旱性，筛选出2份高耐旱种质，为耐旱相关研究及育种提供了评价方法和材料。     

Polymorphisms in the ALS gene of weedy rice (Oryza sativa L.) accessions with differential tolerance to imazethapyr

Herbicide-resistant Clearfield™ rice technology allows the use of ALS inhibitors to control weedy rice. Weedy rice plants have differential tolerance to imazethapyr, perhaps due to ALS polymorphisms. We aimed to assess ALS polymorphisms in weedy rice accessions from Arkansas, USA, with differential tolerance to imazethapyr in seedling growth bioassays. Six base changes were identified in the ALS of 14 weedy rice accessions. Three of these nucleotide changes resulted in amino acid substitutions — Pro⁹³Thr, Glu⁶³⁰Asp, and Val⁶⁶⁹Met — in four accessions: Ark-4, Ark-9, Poi-1 and Poi-6. The GR₅₀ values and inhibition of root and shoot growth (%) of these accessions differed. The Glu⁶³⁰Asp substitution occurs in the herbicide binding domain B and Val⁶⁶⁹Met occurs at the C-terminal tail where the co-factor binds. Variability in weedy rice ALS exists, but polymorphism patterns did not relate to tolerance levels. The observed mutations presented the possibility that sustained selection pressure will eventually lead to selection of a herbicide-tolerant individual that will be the progenitor of a resistant population. Concomitantly, pollen-mediated gene flow from Clearfield™ rice to weedy rice will lead to the evolution of ALS-resistant weedy rice populations.     

Heat and drought stress on durum wheat: Responses of genotypes,yield, and quality parameters

Heat and/or drought stress during cultivation are likely to affect the processing quality of durum wheat (Triticum turgidum L. ssp. durum). This work examined the effects of drought and heat stress conditions on grain yield and quality parameters of nine durum wheat varieties, grown during two years (2008–09 and 2009–10). Generally, G and E showed main effects on all the parameters whereas the effects of G × E were relatively small. More precipitation in Y09–10 may account for the large differences in parameters observed between crop cycles (Y08–09 and Y09–10). Combined results of the two crop cycles showed that flour protein content (FP) and SDS sedimentation volume (SDSS) increased under both stress conditions, but not significantly. In contrast the gluten strength-related parameters lactic acid retention capacity (LARC) and mixograph peak time (MPT) increased and decreased significantly under drought and heat stress, respectively. Drought and heat stress drastically reduced grain yield (Y) but significantly enhanced flour yellowness (FY). LARC and the swelling index of glutenin (SIG) could be alternative tests to screen for gluten strength. Genotypes and qualtiy parameters performed differently to drought and heat stress, which justifies screening durum wheat for both yield and quality traits under these two abiotic stress conditions.     

甘蓝型油菜SERK基因家族的鉴定与系统进化分析

体细胞胚胎发生类受体激酶（somatic embryogenesis receptor-like kinase，SERK）与植物体细胞胚发生，尤其是与植物非生物逆境胁迫响应有关。为鉴定甘蓝型油菜中BnaSERK基因家族成员、揭示其进化关系及其与油菜盐/旱胁迫的响应，利用生物信息学方法对甘蓝型油菜品种中双11的SERK家族成员、基因结构、进化关系、选择压力等进行系统分析，并初步分析了部分BnaSERK基因在盐/旱胁迫下的表达响应模式。结果表明：在甘蓝型油菜基因组共鉴定到24个BnaSERK基因，它们不均等地分布在15条染色体上，可分为3个亚族，具有相对保守的基因结构和保守基序，且含多种与激素和非生物胁迫响应相关的顺式作用元件。共线性分析表明，甘蓝型油菜和拟南芥、白菜、甘蓝分别有14对、44对和32对基因表现出共线性。基于比较基因组学研究，甘蓝型油菜BnaSERK基因在经历多倍体化之后，出现了不同程度的丢失现象。分析表明，BnaSERK基因家族在芸薹属物种间的进化相对保守。盐/旱胁迫下的5个BnaSERK基因在叶片中的表达模式分析结果显示，BnaA07g29610D、BnaC01g43240D、BnaCnng07810D基因在盐胁迫下表达量上调，而BnaA01g23070D、BnaA07g23390D基因则表现为下调；BnaA07g23390D、BnaA07g29610D基因在干旱胁迫下表现为上调表达，而BnaC01g43240D、BnaCnng07810D、BnaA01g23070D基因呈下调趋势。表明BnaSERK基因可能在油菜响应盐/旱胁迫的调控机制中发挥着重要作用。     

异源细胞质小麦的抗旱性研究

以分别具有山羊草属、小麦属和簇毛麦属的15种普通小麦近缘种细胞质的异源细胞质小麦为材料．采用高渗溶液法、水培盆栽法和田间鉴定法研究了异源细胞质对小麦抗旱性的遗传效应。结果表明,波斯小麦（T.persicum）、柱穗山羊草（Ae．cylindrica）、簇毛麦（Hanaldia villosa）和粗厚山羊草（Ae．crassu 6x）细胞质对小麦的抗旱性具有明显的遗传效应。其效应值的性质、大小与核亲毒品种的基因型有关,在特定的核质组合中波斯小麦、柱穗山羊草、簇毛麦和粗厚山羊草细胞质可明显提高小麦的抗旱性。具波斯小麦细胞质的异质系（T．persicum）-s．c66种子发芽阶段和三叶期的抗旱性比相应核亲本明显增强．并且超过抗旱品种晋麦47。成熟期的鉴定结果表明．经核基因型改良的粗厚山羊草细胞质小麦新品系NC223、NC232和NC236等15个异质系具有较强的抗旱性。因此,进一步研究异源细胞质提高小麦抗旱性的遗传机制,有助于拓宽小麦抗旱育种途径。     

Recent Advances in Marker-Assisted Selection for Drought Tolerance in Pearl Millet

Abstract

Pearl millet [Pennisetum glaucum (L.) R. Br.] is the staple cereal of the hottest, driest areas of the tropics and subtropics. Drought stress is a regular occurrence in these regions, making stress tolerance an essential attribute of new pearl millet cultivars. Recent breeding research has mapped several quantitative trait loci (QTLs) for components of grain and stover yield per se, as well as yield maintenance, under terminal drought stress conditions. We report here the evaluation of these QTLs as possible selection criteria for improving stress tolerance of an elite hybrid cultivar. Initial evaluations, based on hybrids made with topcross pollinators bred from lines selected directly from the mapping population, indicated an advantage to the QTL-based topcross hybrids. This advantage seemed to be related to a particular plant phenotype that was similar to that of the drought tolerant parent of the mapping population. Subsequent evaluations were based on testcross hybrids of drought tolerance QTL introgression lines in the background of the drought-sensitive parent of the mapping population, H 77/833-2. These introgression lines were bred by limited marker-assisted backcrossing of a putative major drought tolerance QTL into H 77/833-2 from the mapping population’s drought tolerant parent. Several of these QTL introgression lines had a significant positive general combining ability for grain yield under terminal stress and significantly out-yielded testcross hybrids made with the original recurrent parent both in unrelieved terminal drought stress and in gradient stress evaluations.     

我国常用玉米自交系的耐旱性评价

2007年冬季和2008年春季分别在海南三亚和新疆乌鲁木齐对196份玉米自交系采用两种不同干旱胁迫处理,依据形态性状及产量相关性状评价其耐旱性。通过典型相关分析发现,株高、雌雄开花间隔天数(ASI)、单穗粒重和结实株数百分率4个性状可以作为玉米自交系耐旱性评价指标。采用因子分析方法,计算株高、雌雄开花间隔天数、单穗粒重和结实株数百分率4个性状的综合耐旱系数,对196份玉米自交系进行耐旱性评价,将试验材料分为耐旱、中度耐旱、中度干旱敏感和干旱敏感4种类型。两点试验耐旱级别完全一致的材料有58份,其中耐旱自交系有7份(H201、Mo113、英64、H21、早49、丹598、吉842);中度耐旱自交系有14份(丹黄02、8902、中106、郑22、中黄68、K22等),这些材料为耐旱育种提供了种质基础。     

Characterization of phenotypic diversity,yield and response to drought stress in a collection of Rhodes grass (Chloris gayana Kunth) accessions

Information on available diversity and drought resistance among Chloris gayana accessions would offer considerable potential to select genotypes to alleviate the feed inadequacy that constrains livestock production in dry tropical areas. A collection of 62 C. gayana accessions from the genebank of the International Livestock Research Institute in Ethiopia was characterized using a set of 30 morphological, 4 phenological and 8 agronomic traits to assess diversity within the collection and to select promising accessions for use as livestock feed. In parallel, an experiment was conducted to assess the ability of these C. gayana accessions to maintain productivity under drought stress.     

Development of new markers to genotype the functional SNPs of SSIIa, a gene responsible for gelatinization temperature of rice starch

Gelatinization temperature (GT) is an important quality predictor that determines the cooking quality of rice. GT is genetically controlled by the starch synthase IIa (SSIIa) gene. Two functional single nucleotide polymorphisms (SNPs) inside the SSIIa have already been found to be responsible for the variation of GT. One of these, GC/TT SNP at 4329/4330 bp, could be genotyped by four primers in a single PCR ( Bao et al., 2006a), but another one, G/A SNP at 4198 bp, has not been detected by a PCR-based marker. Here, we developed cleaved amplified polymorphic sequence (CAPS) and derived cleaved amplified polymorphic sequence (dCAPS) markers to detect these SNPs. A dCAPS marker that the PCR products were cleaved by the BseR I restriction endonuclease was designed to detect GC/TT SNP. Both CAPS and dCAPS markers were designed to detect G/A SNP using the restriction endonuclease Nla III and Tsp45 I, respectively. All the markers developed were co-dominant. It was known that the A allele of G/A SNP was rare among rice germplasm, but it was still in use by rice breeders. 11 rice accessions including landrace and breeding lines with A allele of G/A SNP were detected. The F₂ individuals from two crosses were used to analyze the co-segregation between the SNP alleles and the GT. The segregation ratio of two SNPs did not conform to the expected Mendelian ratio of 1:2:1, but the SNPs were co-segregated with GT. The markers developed in the present study would be useful in molecular breeding for the improvement of the quality of rice grain.     

春小麦育种材料抗旱性和穗发芽抗性分子标记鉴定

为给春小麦生育早期抗旱和收获期抗穗发芽育种提供抗性亲本,利用与小麦抗旱性相关的分子标记TaNRX-B1a1、TaNRX-B1b1和FerA1-intrl以及与小麦穗发芽抗性相关的分子标记Vp1B3、Vp1A3和Tamyb10D对137份内蒙古春小麦育种材料进行检测。结果表明,73B609等共58份材料的抗旱性分子标记均属于抗旱基因型,占供试材料的42.34%,其单倍型组合为TaNRX-B1a/TaFer-A1a,可以用作抗旱育种的亲本材料。中国春既属于Vp-1Bb等位基因类型,同时用标记Tamyb10D检测时也属于抗穗发芽类型。辽春10号在3个分子标记的检测中均属于抗穗发芽的等位基因类型,同时又是TaNRX-B1a/TaFer-A1a单倍型,所以辽春10号在抗穗发芽和抗旱性聚合育种中可以作为亲本使用。