Characterization of an RNase Z nonsense mutation identified exclusively in environment-conditioned genic male sterile rice

The two-line hybrid system in rice is becoming more important and employs environment-conditioned genic male sterile (EGMS) lines sensitive to photoperiod (photoperiod-sensitive genic male sterile), temperature [temperature genic male sterile (TGMS)], or a combination of the two (photoperiod temperature genic male sterile). At least 18 EGMS genes have been mapped, and two cloned, but controversies exist. For example, three different genes were reported to underlie the TGMS trait in three independently identified progenitors, Annong S-1, Zhu 1S, and Guangzhan 63S, while another study demonstrated that the TGMS genes in Annong S-1 and Zhu 1S are allelic. In the present study, we confirmed the allelism of the three TGMS genes, which means there is a common TGMS gene(s) in these lines. Knowing there is an association between the mutant allele (RNZ ^m ) of a ribonuclease gene (RNZ) with the TGMS trait in Guangzhuan 63S, we then sequenced RNZ for 14 commercial EGMS and 21 non-EGMS lines, and we developed two derived cleaved amplified polymorphic sequence (dCAPS) markers to detect RNZ ^m alleles in 32 EGMS and 310 non-EGMS lines. The analyses showed that the RNZ ^m allele existed exclusively in EGMS lines; all non-EGMS lines contained the functional RNZ ^gc or RNZ ^tc allele. Furthermore, two segregating populations that included 2,429 individuals were developed by crossing Zhu 1S (RNZ ^m ) to two non-EGMS lines (both with RNZ ^tc ); examination of the segregation of male sterile and fertile plants indicated that the TGMS trait was under the control of a single gene; analysis of the markers revealed the RNZ ^m allele exclusively in TGMS plants and the RNZ ^tc allele only in non-TGMS plants in both populations. The dCAPS markers could therefore help select TGMS progeny in breeding programs, which will save time and labor, and improve breeding efficiency and accuracy.     

广适性光温敏不育系Y58S幼穗分化期耐冷性表现及生理机制

为了阐明水稻光温敏不育系幼穗分化期耐冷的形态生理机制,以耐冷不育系Y58S和4个生产上常用光温敏不育系为试验材料,研究了低温胁迫(17.5℃,10 d)下结实率、穗部形态、株高、光合特性以及抗氧化物酶系统等的变化。结果表明,低温胁迫下Y58S的幼穗分化期耐冷性在5个不育系中最强,与敏感的C815S和株1S相比,Y58S表现为株高和穗长降低幅度较小,保持较高结实率;光合作用受低温影响不显著,SPAD值、光合速率等光合指标无显著变化;SOD、POD活性降低幅度较小,MDA含量、相对电导率增幅较小。     

Cytological observation of two environmental genic male-sterile lines of rice.

We report here two environmental genic male-sterilities (EGMS) in rice. These two EGMS rice lines, thermo-sensitive genic male-sterility (TGMS) and photoperiod-sensitive genic male-sterility (PGMS), are controlled by temperature and photoperiod, respectively, in determining their male-sterility. Male-sterility of the TGMS and PGMS was found to be induced when they were grown at 32 degrees C/26 degrees C (day/night) with 14 h daylight, while they were fertile at 26 degrees C/20 degrees C (day/night) with 10 h daylight in a growth chamber. We also examined their anther structures under a light microscope. The light microscopic observation revealed that the EGMS lines showed a complete pollen abortion at the sterile growth condition while they produced normal fertile pollens at the fertile growth condition.     

Genotyping the Heading Date of Male-Sterile Rice Line II-32A

II-32A, an elite male-sterile line of rice （Oryza sativa L.）, has been widely used for the production of hybrid rice seed In China. Heading date In most combinations using II-32A shows transgressive Inheritance or similarity to the latter parent, but the genotype of II-32A with respect to major genes for heading time Is unknown. This limits the further exploitation of this sterile line In breeding and hybrid seed production. Using a number of major gene heading date Isogenlc lines and heading date QTL near-lsogenic lines, we genetically analyzed II-32B under both long- and short-day conditions. We show that II-32B carries two photoperlod-sensltlve genes, E1 and E3, a recessive late-heading gene, ef-l, and a photoperlod-sensltlve allele, Se-1^u. In addition we Identified In II- 32B a recessive Inhibitor for E1 or Se-1^n and other modified photoperlod-sensltlve genes. The heading-date constitution of II-32A was determined to be E1e2E3Se-1^uef-li-Se-1.     

Genotyping the Heading Date of Male-Sterile Rice Line Ⅱ-32A

Ⅱ-32A, an elite male-sterile line of rice (Oryza sativa L.), has been widely used for the production of hybrid rice seed in China. Heading date in most combinations using Ⅱ-32A shows transgressive inheritance or similarity to the latter parent, but the genotype of Ⅱ-32A with respect to major genes for heading time is unknown. This limits the further exploitation of this sterile line in breeding and hybrid seed production. Using a number of major gene heading date isogenic lines and heading date QTL near-isogenic lines, we genetically analyzed Ⅱ-32B under both long- and short-day conditions. We show that Ⅱ-32B carries two photoperiod-sensitive genes, E1 and E3, a recessive late-heading gene, ef-1, and a photoperiod-sensitive allele, Se-1u. In addition we identified in Ⅱ-32B a recessive inhibitor for E1 or Se-1n and other modified photoperiod-sensitive genes. The heading-date constitution of Ⅱ-32A was determined to be E1e2E3Se-1Uef-1i-Se-1.     

Distinguishing among male sterile and fertile lines of tomatoes (Lycopersicon esculentum Mill.) by means of electrophoretic protein patterns

Vertical block SDS-PAAG electrophoresis of individual tomato seeds was used to examine the potential of seed proteins as gene markers for distinguishing male sterile from fertile lines and cultivars. Seeds of three genic male sterile lines and four fertile cultivars and lines were investigated. The line 6944 is carrier of the gene ms 10 ³⁵for pollen male sterility and the lines P-1a and PPS-3 carry the gene ps-2 for positional sterility. A modified extract solution which includes 1M tris — buffer pH 7.0, 7 % SDS, dimethylformamide and distilled water was applied. Qualitative variation in the A protein locus which could be used as a marker for distinguishing male sterile from fertile tomato lines was established.     

抗除草剂杂交籼稻亲本的配合力分析

本试验以6份新育成的抗除草剂籼型恢复系为父本,5份生产上广泛应用的不育系为母本,采用不完全双列杂交设计配制了30份杂交组合,对其苗期除草剂抗性和主要农艺性状配合力进行了分析。除草剂抗性鉴定表明,亲本恢复系及三系杂交组合抗性接近完全,两系杂交组合抗性达90%以上。配合力分析表明,不育系除单株有效穗数外其他农艺性状的一般配合力均达到极显著差异;恢复系间一般配合力在所有性状中均达到显著或极显著差异;杂交组合间特殊配合力方差仅在单株产量、结实率、播始历期和千粒重4个性状中达到显著或极显著差异。不育系中,金科1A在单株产量、结实率等7个性状上的一般配合力均为最高,但其特殊配合力方差最小;广占63-4S在千粒重性状上具有最高的一般配合力、最大的特殊配合力方差,在播始历期上具有最高的一般配合力负效应;C815S在株高上的一般配合力负效应最大,同时特殊配合力方差较高。恢复系中,华抗恢101在单株有效穗数上具有最高的一般配合力和特殊配合力方差;华抗恢104在穗长上具有最高的一般配合力,在播始历期上具有最高的一般配合力负效应;华抗恢105在单株产量、结实率等性状上具有最高的一般配合力,在株高上具有最高的一般配合力负效应;华抗恢106在千粒重性状上具有最高的一般配合力和特殊配合力效应方差。利用抗除草剂恢复系配制杂交组合,不仅可以改良其除草剂抗性,也可以通过广泛测配,选择一般配合力强、特殊配合力方差大的亲本配组育成强优势组合。     

花药培养对籼稻两用核不育系培矮64S的提纯与改良

以籼稻两用雄性核不育系（简称两用系）培矮６４Ｓ为供体,通过花药培养,获得了２６个愈伤系共１９６９株花粉植株。根据花粉一代（Ｈ１）的倍性和育性,可把它们分为三种类型,即ａ）单倍体：有１个愈伤系４１株全为单倍体植株;ｂ）不分离型：有１９个愈伤系的群体育性不分离,全部植株均在不育期表现败育,其它性状有差异但不显著;ｃ）分离型：其余６个愈伤系表现分离,其中３个各有２－７株单倍体植株出现,并且这些愈伤系中均     

甘蓝型油菜雄性不育系160S育性转换与利用

以甘蓝型油菜雄性不育系160S为试验材料,分别在自然栽种和人工控温条件下对其花器官形态变化、花粉育性转换和杂种优势等进行了初步研究,以探讨植物温敏雄性不育的发生机制。结果表明:环境温度对160S的花器官形态及育性转换具有明显的作用,高温可使花瓣变小,雄蕊退化,花粉活力、角粒数与自交有效结角率降低,表现为低温可育、高温不育,育性变化趋势表现为完全可育-半不育-彻底败育。160S恢复源广泛,且具有较好的配合力和杂种优势,为利用两系法生产油菜杂交种提供了一个较好的途径。     

Fertile revertants from S-type male-sterile maize grown in vitro

Summary Plants were regenerated from callus cultures of maize inbred W182BN with the S(USDA) type of cytoplasmic male sterility (cms). Some regenerates from 16 of 18 separate cultures had fertile tassels. Many other regenerates, whose fertility could not be scored accurately because of abnormal plant morphology, produced fertile progeny after pollination with N cytoplasm W182BN. Revertant plants and/or progeny were obtained from all 18 cultures, which included the CA, D, LBN, and S sources of cmsS. More revertants were recovered from cultures maintained as callus for 12 months than from 3–4 month old cultures. Several types of evidence (absence of segregation for fertility after selfing or pollination of revertants with standard W182BN, pollen viability counts, failure of revertants to restore sterile cmsS lines to fertility, mitochondrial DNA analyses) indicated that the reversion to fertility involved cytoplasmic rather than nuclear alterations. All revertants examined lacked the S1 and S2 plasmid-like DNAs characteristic of the mitochondrial genome of sterile cmsS lines. Most callus cultures lost S1 and S2 after 13–20 months in vitro. No revertants were seen among thousands of W182BN cmsS plants grown from seed in the field or among plants from tissue cultures of W182BN with the C or T types of cms. The cytoplasmic revertants recovered from culture may be useful for the molecular analysis of cmsS.     

水稻转座子突变体库的构建及突变类型的遗传分析

利用根癌农杆菌介导的遗传转化法,把玉米转座子Ac片段(合成转座酶)和Ds因子(转座序列)分别导入粳稻品种中花11,获得了400多个转化株系。有63个株系的转基因T₀代植株或T₁代植株出现了可见的形态变异,包括抗病、白苗、黄苗、白条斑叶、有色秆、矮秆、匍匐茎、雄性不育、抽穗早、抽穗迟、多倍体等突变类型。对突变性状的形态及分子生物学分析,有些突变类型可能与转座子插入有关。     

Mapping quantitative trait loci controlling seed dormancy and heading date in rice, Oryza sativa L., using backcross inbred lines

 To detect quantitative trait loci (QTLs) controlling seed dormancy, 98 BC₁F₅ lines (backcross inbred lines) derived from a backcross of Nipponbare (japonica)/Kasalath (indica)//Nipponbare were analyzed genetically. We used 245 RFLP markers to construct a framework linkage map. Five putative QTLs affecting seed dormancy were detected on chromosomes 3, 5, 7 (two regions) and 8, respectively. Phenotypic variations explained by each QTL ranged from 6.7% to 22.5% and the five putative QTLs explained about 48% of the total phenotypic variation in the BC₁F₅ lines. Except for those of the QTLs on chromosome 8, the Nipponbare alleles increased the germination rate. Five putative QTLs controlling heading date were detected on chromosomes 2, 3, 4, 6 and 7, respectively. The phenotypic variation explained by each QTL for heading date ranged from 5.7% to 23.4% and the five putative QTLs explained about 52% of the total phenotypic variation. The Nipponbare alleles increased the number of days to heading, except for those of two QTLs on chromosomes 2 and 3. The map location of a putative QTL for heading date coincided with that of a major QTL for seed dormancy on chromosome 3, although two major heading-date QTLs did not coincide with any seed dormancy QTLs detected in this study. Received: 10 October 1997 / Accepted: 12 January 1998     

Aanlysis of short photo-periodic sensitive genic male sterility and molecular mapping of rpms3(t) gene in rice (Oryza sativa L.) using SSR markers

A research was conducted on the pollen fertility of rice sterile lines D52S and D38S responsive to photoperiod during the sensitive stage under natural and controlled conditions. Bulk segregant analysis (BSA) and recessive class approach were applied to identify DNA markers that co-segregate with gene conferring male-sterility in D52S mutant rice. The results showed that in day-light higher or equal to 14.00 h, D52S and D38S rice pollen were fertile; however, they were sterile when day-length was less than 14.00 h. They were therefore considered to be short photo-periodic sensitive genic male sterile lines(Short PGMS lines). Under short day-light conditions, the pollen fertility segregation of F₂ populations from crosses between D52S/Shuhui527 and D52S/Gui99showed 3:1 ratio of fertile to sterile plants suggestingthat male sterility in D52S was controlled by one recessive gene. Two markers RM244 and RM216 located on chromosome number 10 co-segregated completely with the rpms locus. The locus was mapped to the interval between SSR markers RM2571 (6.6 cM) and RM244 (4.6 cM).     

水稻雄性不育系珍汕97A抽穗期的基因型分析

水稻雄性不育系珍汕97A是我国应用最大,使用最广泛的不育系,利用抽穗期基因型明确的秋光（e1e1e2e2e3e3se-1^eSe-1^e),越光（E1E1E2E2e3e3Se-1^eSe-1^e),日本晴（E1E1e2e2e3e3Se-1Se-1)和日光（E1E1E2E2e3e3Se-1Se-1)作测验品种,分析了水稻珍汕97B的抽穗期基因型,结果表明,珍汕97B的抽穗期感光基因型为：e1e1e2e2E3E3Se-1Se-1,同时还存在1对隐性感光抑制基因i-Se-1,进一步用QTL近等基因系NIL（Hd1),HIL(Hd2),NIL(Hd3),NIL(Hd5)和NIL（Hd6)进行的实验也验证了珍汕]97B 在1个显性的主效感光基因Se-1,以及其他感光修饰基因,如E3,Hd3(En-Se-1),Hd5和Hd6的基因的作用。因此,推测珍汕97A带有主效感光基因是其配制的灿型杂交稻抽穗期超亲表现的内因。     

K型温敏雄性不育系KTP116A育性转换规律的研究

基于两系杂交小麦系统的K型（Aegilops kotshyi）细胞质小麦温敏雄性不育系,在中国北方小麦正常生长季节表现完全雄性不育,可用于杂交小麦种子生产,在反季节播种表现育性部分恢复,是一类非常有利用价值的小麦温敏雄性不育系。本研究以小麦温敏雄性不育系KTP116A为材料,采用人工气候箱控温和涂抹法压片的方法对其育性转换的关键时期及败育的花粉发育过程进行更为精细的研究。研究发现,KTP116A可育环境下能正常进行减数分裂并发育为成熟花粉粒;不育环境下只有少数能经过第二次有丝分裂产生两个精细胞,大部分为二核期花粉粒、异常花粉粒和没有原生质体的空壳花药不开裂,自然条件下不散粉;KTP116A育性敏感期为两个时期,减数分裂期至单核早期和二核晚期至三核期,在自然条件下温度感应历期为10d左右;从小麦外部发育进程来看,抽穗前的2-8d和扬花前的3-5d为其敏感时期。这对于进一步研究败育的机理,分析败育的原因和更好的利用温敏不育系奠定基础。     

两个籼型水稻核不育系育性温光反应的研究

在杭州男单通过分期播种,比较了两个籼稻光温敏核不育系的育性及其转换特性。结果表明,光照长度对浙大247S和培矮64S两不育系育性表达的影响小,温度起主导作用,均属温敏型不育系,且日最低温度对不育系育性效应显著高于日平均温度和日最高温度。不育系浙大247S和培矮64S的温度敏感期分析是抽穗前3-18和6-21d,育性转换的临界日期为9月19日和9月25日,转换临界温度为25.28和25.66℃,与培矮64S相比,浙大247S不育期败育较彻底,可育期较长且自交结实率高,在杭州田间可以繁种。     

Structural analysis and identification of cis-elements of rice osRACD gene

Sexual reproduction in many plants is sensitive to thechange of day-long and photoperiod. It was discoveredby Shi et al. [1] in 1973 that the natural mutant Nongken58S is infertile under long day while being fertile undershort day. In recent two decades, much work has beendone to probe into its molecular mechanism from variousperspectives, such as physiology, genetics as well asmolecular biology [2,3]. The previous study showed thatphysiological changes of 58S rice could be dependent oncombi…     

在杂交作物分子育种中利用普通核雄性不育的几个可能途径

由一对隐性基因控制的普通核雄性不育性遗传方式能够满足对植物最佳雄性不育系选育的要求,是水稻等作物杂种优势利用的极好遗传工具。如果能解决其不育系繁殖问题,将优于现有的其他杂种优势利用方式。克隆出普通核雄性不育性的可育基因,通过叶绿体转化,将核雄性不育性可育基因向普通核雄性不育株细胞质转移,创造普通核雄性不育株的保持系;通过种子成熟后表达的启动子;和以位点特异性重组技术为基础的基因开关以及化学诱导启动子的利用,都可能繁殖出100%不育株率的普通核雄性不育系,创造普通核雄性不育性利用的新途径,对植物杂种优势利用产业有十分重要的意义。     

在杂交作物分子育种中利用普通核雄性不育的几个可能途径

由一对隐性基因控制的普通核雄性不育性遗传方式能够满足对植物最佳雄性不育系选育的要求,是水稻等作物杂种优势利用的极好遗传工具。如果能解决其不育系繁殖问题,将优于现有的其他杂种优势利用方式。克隆出普通核雄性不育性的可育基因,通过叶绿体转化,将核雄性不育性可育基因向普通核雄性不育株细胞质转移,创造普通核雄性不育株的保持系;通过种子成熟后表达的启动子;和以位点特异性重组技术为基础的基因开关以及化学诱导启动子的利用,都可能繁殖出100％不育株率的普通核雄性不育系,创造普通核雄性不育性利用的新途径,对植物杂种优势利用产业有十分重要的意义。     

CHK1-regulated S-phase checkpoint response reduces camptothecin cytotoxicity

The cytotoxicity of camptothecin (CPT) is S phase specific and is associated with an inhibition of DNA replication. The relationship between CPT-induced inhibition of DNA replication and CPT cytotoxicity remains unclear. We previously reported that the CPT-induced inhibition reflects an activated S-phase (S) checkpoint response and that this response is mainly regulated by ATR/CHK1 pathway. In this study, by comparing A1-5 and B4, the two transformed rat embryo fibroblasts cell lines, we showed that with higher CHK1 expression, A1-5 cells had a stronger S checkpoint response and were more resistant to CPT-treatment. The data suggested that over-activated CHK1 in CPT-treated A1-5 cells regulated the strong S checkpoint response through the CDC25A/CDK2 pathway. When the CHK-1 regulated strong S checkpoint response was abolished, A1-5 cells became much more sensitive to CPT-induced killing. These data indicated that CHK1 regulated S checkpoint response protected cells from CPT-induced killing.