水稻花器官数目突变体fon6的研究初报

fon6是在籼稻恢复系乐恢188/明恢62杂交F3代发现的花器官数目突变体,表型分析结果表明:该突变体小花颖壳畸形扭曲、内颖长于外颖不闭合;每朵小花内外颖壳总数目2～4片;雄蕊数目为1～14枚;雌蕊数目增加,子房数目2～6个,胚囊畸形。突变体套袋自交结实率为14.06%,花粉活力较高,平均花粉可染率为91.86%。自交种子能正常萌发成苗,突变性状表现稳定的遗传特性。以突变体为父本分别与蜀恢527、明恢63杂交,F2代群体中正常株与突变株的分离均符合3∶1的比例,F3代及BC1F2代进一步的观察与统计结果均表明,该突变性状受1对隐性核基因控制,将该突变基因暂定名为fon6(floral organ number6)。     

一个由可变剪接造成的水稻开颖不育突变体ohms1的鉴定及基因定位

在60 Co-γ射线辐射诱变籼稻中恢8015的突变体库内发现了一个花器官发育突变体,暂命名为开颖不育突变体ohms1(open hull and male sterile 1)。ohms1突变体表现为颖花开裂,在雄蕊和柱头之间形成类似内外稃的结构,使得突变体的颖花形成类似"三齿稃"状的三个颖壳,小穗完全不育,花粉育性为60%~70%,但自交不结实。遗传分析和基因定位结果表明,ohms1受一对隐性单基因控制,位于第3染色体短臂KY2和KY29标记之间,物理距离约42kb,该区域包含4个开放阅读框ORFs。进一步序列分析发现,突变体中一个编码MADS盒的基因LOC_Os03g11614的第5内含子末位碱基由A突变为G。酶切实验和cDNA测序证实,该基因的第5内含子未被剪切,致使该基因的第6外显子所编码的14个氨基酸完整缺失,但并未造成该蛋白MADS结构域的改变或移码。qRT-PCR结果显示,突变体中OsMADS1基因的表达水平显著降低,水稻开花调控因子和内外稃发育调控基因的表达量也发生了显著变化。说明该基因对水稻花器官发育尤其是内外稃发育和小花原基的分化具有重要作用。     

水稻多雌蕊突变体K940的发现与初步利用

水稻多雌蕊突变体K940是宜宾市农业科学院利用远缘多基因聚合杂交,在F2代中发现并经多年纯合选育而成。该突变体每穗颖花数多,颖花中雄蕊数减少,雌蕊数增加,有雄蕊雌蕊化现象,多子房,多柱头,内外稃变形退化,结实种子无颖壳。初步研究表明,其突变性状受隐性基因控制,表现出稳定的遗传特性。K940含有恢复基因,以其为亲缘杂交育成了多个重穗型强优新恢复系。     

水稻雄蕊雌蕊化突变体的遗传分析

在杂交育种后代中发现了一个水稻雄蕊雌蕊化突变体 ,表现为 :外颖和内颖变窄 ,外颖弯曲呈弯月形 ,内外颖不闭合 ,1～5枚雄蕊转变为雌蕊或雌蕊 雄蕊嵌合体。由于高度雌性不育 ,突变纯合体本身无繁殖保持功能 ,只能通过杂合体繁衍 ,在自交 15代后仍分离出完全相同的突变体 ,表现稳定遗传特性。遗传分析表明该突变体由单隐性基因控制。     

水稻新裂颖突变体sg1的遗传分析与基因定位

从中籼3037辐射突变体库中获得一个颖花开裂突变体(split glume1,sg1),表型分析发现该突变体不仅颖壳异常,且伴随着生育期提前,植株变矮,颖花退化等现象,结实率也显著降低。遗传分析和分子生物学分析结果表明该突变受1对隐性核基因控制,并最终将其定位在水稻第1染色体上分子标记M1-z21与M1-z27之间,物理距离约为47kb,这是一种控制颖花发育的新基因,通过预测发现该区段内存在6个开放阅读框。     

水稻T DNA插入雄配子不育突变体的创建

 对6000多个转基因T DNA插入水稻株系进行异常遗传分离分析（选择标记基因为潮霉素磷酸转移酶基因hpt）,发现216个转基因株系的T DNA呈现1∶1分离。接着利用测交方法检测T DNA的遗传规律,初步确定其中57 个候选株系为雄配子不育候选突变体。随后对候选突变株进行多代遗传分析及花粉细胞学观察,结果表明其中的38个突变体花粉黑染率约为50％,自交后代T DNA的异常分离是由于转基因植株的花粉半不育所致,T DNA的传递只能通过雌配子体。另外,利用ELISA定量测定突变体中cry1Ac(Bt)基因编码蛋白的表达量,发现花粉的这种不育性与外源基因的表达量之间没有直接关系,推测这38个雄配子突变体败育的原因主要是T DNA插入引起内源基因变异。TAIL PCR 获得了22个水稻雄配子不育T DNA 插入突变体的侧翼序列,通过BLAST检索,定位了15个不同的插入位点,其中12个插入位点位于基因区或基因调控区。     

水稻茎秆螺旋突变体ts-ta的鉴定及其遗传分析

 从6000个水稻T DNA插入突变体库中筛选到1个苗期茎秆呈螺旋生长，成株期株型松散，植株矮化，抽穗延迟的突变体ts ta。取突变体弯曲的叶鞘做石蜡切片发现，突变体弯曲的叶鞘周围表皮细胞完整，但两侧细胞的大小不同。弯曲内侧细胞小，排列紧密，外侧细胞较内侧大。T1 、T2及回交结果表明，该突变体能稳定遗传且受一对隐性单基因控制，共分离分析表明该突变性状不是由于T DNA插入引起的，因此不能通过T DNA 标签法克隆该基因。     

水稻颖壳类病斑突变体glmm1的鉴定与基因定位

【目的】鉴定水稻颖壳类病斑突变体，并进行基因定位，为基因克隆及其分子机制研究奠定基础。【方法】对野生型材料LR005和经EMS诱变得到的颖壳类病斑突变体glmm1(glume lesion mimics mutant 1)进行农艺性状分析、扫描电镜分析、DAB染色和全硅含量测定。glmm1与广亲和材料L422杂交获得的F2群体用于遗传分析，利用图位克隆和BSA-seq方法进行基因定位。【结果】突变体glmm1在抽穗10 d后颖壳和叶片逐渐出现褐色斑点，成熟后颖壳完全呈现褐色。与野生型相比，突变体的株高、穗长、每穗总粒数、结实率和千粒重等都极显著降低。DAB染色表明glmm1颖壳和叶片的活性氧含量增多；扫描电镜显示突变体颖壳和叶片表面硅质细胞皱缩。遗传分析结果表明，突变体glmm1的颖壳类病斑表型受到一对隐性基因控制。利用glmm1与L422的F2分离群体，通过图位克隆和BSA-seq等策略将glmm1定位在水稻第2染色体上68 kb的区间内。该区间内有10个候选基因。序列分析发现该区间仅有一个SNP位点，位于基因Lsi1(LOC＿Os02g51110)的第5个外显子上，导致第238位氨...     

水稻裂颖突变体sh1的鉴定及基因定位

[目的]本研究旨在定位和克隆水稻裂颖基因,为解析水稻裂颖性的遗传机制提供依据。[方法]从籼稻品种湘早籼6号突变体库中筛选出一个裂颖突变体(split husk 1, sh1),观察突变体的花器官和浆片形态,利用突变体与02428的F2群体定位目标基因,进一步通过定量 PCR 分析相关基因的表达情况。[结果]sh1 突变体的颖花形态与野生型基本一致,能正常开花,但不能正常闭颖,裂颖的主要原因是浆片不能在开颖后正常萎蔫。sh1突变体的有效穗数增加,但结实率和千粒重显著下降;遗传分析表明,sh1的裂颖表型受一对隐性核基因控制。将SH1 基因定位在ID19827与ID19884两个InDel标记之间,物理距离约为110 kb。定位区间测序发现,突变体中丙二烯氧化合酶编码基因OsAOS1发生单碱基突变,导致氨基酸发生改变;SH1基因的突变显著降低了花器官中的茉莉酸含量,进而影响了茉莉酸合成及信号转导相关基因的表达。[结论]SH1基因通过影响茉莉酸的合成和信号转导调控水稻闭颖,OsAOS1可能是 SH1基因的候选基因。     

水稻小粒矮秆突变体sgd1(t)的表型分析及基因克隆

在日本晴T-DNA突变体库中筛选得到小粒矮秆突变体sgd1(t),经多代自交稳定遗传。sgd1(t)出现植株矮化、粒型圆小、叶色深绿和颖壳厚实等表型。茎秆及颖壳细胞扫描电镜结果表明,sgd1(t)茎秆细胞不能形成正常细胞列、维管束发育异常;颖壳表皮细胞排列紧密但不规则;GA信号转导途径响应正常。遗传分析表明突变体sgd1(t)的矮秆性状受一对隐性核基因控制。采用图位克隆方法,将sgd1(t)定位于第9染色体短臂Indel标记DF13和DF26之间,物理距离约为230kb。该区间存在已克隆的矮秆基因BC12/GDD1。测序结果显示,sgd1(t)在该基因第4个外显子发生由G到T的单碱基突变,导致第186位保守氨基酸由甘氨酸突变为缬氨酸。     

Morphogenesis, Anatomical Observation and Primary Genetic Analysis of a Multi-glume Floral Organ Mutant in Rice

The floral development is one of the pivotal characteristics of the transition from vegetative to reproductive phase in plant, while the generated seeds are the important source of propagation and population dispersal. Furthermore, it serves as the foundation of grain yield and quality in crop. Therefore, the floral development and its regulation becomes current research hotspot in plant molecular biology. Previously, some genes controlling flower development have been cloned in Snapdragon and…     

Characterization and Genetic Analysis of a Novel Mutant mst of Rice Defective in Flower Development

A spontaneous mutant with multiple stigmas (mst) was found in an indica rice line 466. The mst mutant exhibits normal at the vegetative development stage and produces normal inflorescence structures. The difference between the mutant and the wild type was observed when the stamen primordium began to develop. In the mst florets, palea and lemma opened, lodicules were homeotically transformed into palea/lemma-like structures, and stamens were homeotically transformed into carpel-like structures. It looked like multiple stigmas being full of the whole floret. The phenotypic changes of mst were very similar to that of B-like mutant spw1. Compared with other mutants with pistillate morphologies, the severe mst florets showed that the inner three floral organs were completely changed into palea/lemma-like structures. Moreover, the mutant was female sterile. Occasionally, with the changing environment, one or two stamens were fertile. Genetic analysis indicated that the mutant traits were controlled by a single recessive gene.     

Genetic Analysis of Streaked and Abnormal Floret Mutant st-fon

A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant (st-fon).For this mutant,besides white streak appeared on culm,leaves and panicles,the number of floral organs increased and florets cracked.The extreme phenotype was that several small florets grew from one floret or branch rachis in small florets extended and developed into panicles.By using transmission electron microscope to observe the ultrastructure of white histocytes of leaves at the seedling stage,the white tissues which showed abnormal plastids,lamellas and thylakoids could not develop into normal chloroplast,and the development of chloroplast was blocked at the early growth stage of plastid.Scanning electron microscope and paraffin section were also used to observe the development of floral organs,and the results indicated that the development of floral meristem was out of order and unlimited,whereas in the twisty leaves,vascular bundle sheath cells grew excessively,or some bubbly cells increased.Genetic analyses carried out by means of cross and backcross with four normal-leaf-color materials revealed that the mutant is of cytoplasm inheritance.     

水稻裂颖突变体sh1的鉴定及基因定位

【目的】本研究旨在定位和克隆水稻裂颖基因，为解析水稻裂颖性的遗传机制提供依据。【方法】从籼稻品种湘早籼6号突变体库中筛选出一个裂颖突变体(split husk 1, sh1)，观察突变体的花器官和浆片形态，利用突变体与02428的F2群体定位目标基因，进一步通过定量PCR分析相关基因的表达情况。【结果】sh1突变体的颖花形态与野生型基本一致，能正常开花，但不能正常闭颖，裂颖的主要原因是浆片不能在开颖后正常萎蔫。sh1突变体的有效穗数增加，但结实率和千粒重显著下降；遗传分析表明，sh1的裂颖表型受一对隐性核基因控制。将SH1基因定位在ID19827与ID19884两个InDel标记之间，物理距离约为110 kb。定位区间测序发现，突变体中丙二烯氧化合酶编码基因OsAOS1发生单碱基突变，导致氨基酸发生改变；SH1基因的突变显著降低了花器官中的茉莉酸含量，进而影响了茉莉酸合成及信号转导相关基因的表达。【结论】SH1基因通过影响茉莉酸的合成和信号转导调控水稻闭颖，OsAOS1可能是SH1基因的候选基因。     

水稻花器官发育基因DPS2的鉴定和精细定位

【目的】鉴定和克隆花器官发育相关基因,为进一步研究水稻花发育的分子机制奠定基础。【方法】在大田常规种植条件下比较了突变体dps2 (Defective pistil and stamens 2)和野生型春江06的主要农艺性状及花器官形态特征差异;扫描电镜及石蜡切片观察花药结构并用染色法观察花粉和胚囊的育性;利用图位克隆方法进行基因精细定位;qRT-PCR分析了花发育相关基因在野生型和突变体中的表达水平。【结果】dps2突变体抽穗期变长,不能正常扬花,雄蕊和雌蕊皱缩且花药和柱头数目增多;进一步研究发现,dps2突变体花药腔室塌陷,内无可见小孢子,即使部分花药形成腔室,花粉粒也无淀粉积累呈干瘪状。此外,突变体胚囊育性也受到影响;遗传分析表明该突变性状受一对隐性核基因控制,该基因位于第4染色体短臂上91.2 kb的区间内,区间内未见花器官发育相关基因的报道。qRT-PCR检测发现,水稻ABCDE模型中的B类、C类和E类基因的表达在突变体中显著升高。【结论】dps2突变体的雄蕊及雌蕊均发育异常,最终导致完全不育,推测DPS2可能在水稻第3轮雄蕊发育和第4轮雌蕊发育调控中发挥重要作用。     

一个水稻双子房突变体的表型鉴定和遗传分析

在籼稻保持系C2与绵香5B的杂交后代中发现了一个植株显著矮化的双子房突变体。该突变体花器官主要表现为：雄蕊数目减少,雌蕊增加,双子房,多柱头,胚囊畸形,有雄蕊雌蕊化现象。由于其高度不育,突变性状采用杂合体保存,经5代连续自交,均表现稳定遗传特性。同时,杂合株系呈典型的3∶1分离比例,表明该突变性状由单隐性基因控制,并将该突变体暂时命名为TOR。     

Radiation effects on potential number of grains per spike and biomass partitioning in two- and six-rowed near isogenic barley lines

The critical period for yield determination in barley (Hordeum vulgare L.) is situated in the pre-heading phases. During the latest part of the critical period one of the most important yield components (i.e. the number of grains per spike) is set in two- and six-rowed barley. In wheat, much is known about the role of the spike in assimilate acquisition for the establishment of grains per spike, but not in barley. This paper evaluates how biomass partitioning between vegetative and reproductive organs impacts floret development and primordia survival in response to radiation during different periods in the crop cycle, in barley lines. Field experiments were carried out using two- and six-rowed near isogenic barley lines differing only in spike type. Shading treatments were applied at different periods during the crop cycle (from 60 to 15 days before and after heading) reducing the intercepted radiation (ca. 70%). Dynamics of floret primordia initiation and mortality and of floret development for different spikelet positions along the spike were measured, and biomass partitioning between vegetative and reproductive structures was calculated.

Pre-heading shading reduced fertile florets per spike (P < 0.001). In the immediate pre-heading treatment, distal floret primordia could not reach a fertile floret stage due to a low rate of floral development.

The amount of assimilates partitioned to the spike at heading affected the number of fertile florets per spike in both barley types. However, when spike biomass at heading was corrected by nitrogen concentration, the fitness of the relationship did not improve in relation to the first one. In relative terms, radiation restrictions during the immediate pre-heading phase increased the amount of biomass partitioned to the growing spike.