Genetic Analysis and Mapping of a Thermo-sensitive White Stripe-Leaf Mutant at Seedling Stage in Rice(Oryza sativa)

A thermo-sensitive white stripe-leaf mutant （tws） was selected from the M2 progeny of a japonica variety, Jiahua 1, treated by ^60 Co γ-radiation. In comparison with the wild type parent, the mutant displayed a phenotype of white stripe on the 3rd and 4th leaves, but began to turn normal green on the 5th leaf when grown at low temperatures （20℃ and 24℃）. Furthermore, the content of total chlorophyll showed an obvious decrease in the leaves with white stripe. These results suggest that the expression of the mutant trait was thermo-sensitive and correlated with the leaf age of seedlings. The genetic analysis indicated that the mutant trait was controlled by a single recessive nuclear gene, designated as tws. In addition, by using SSR markers and an F2 segregating population derived from the cross between the tws mutant and 9311, tws was mapped between the markers MM3907 and MM3928 with a physical distance of 86 kb on dce chromosome 4.

Genetic Analysis and Molecular Mapping of Novel White Striped Leaf Mutant Gene in Rice

A new white striped leaf mutant wsll was discovered from Nipponbare mutated by ethyl methanesulfonate. The mutant showed white striped leaves at the seedling stage and the leaves gradually turned green after the tillering stage. The chlorophyll content of wsll was significantly lower than that of wild-type during the fourth leaf stage, tillering stage and booting stage. The numbers of chloroplast, grana and grana lamella were reduced and the thylakoids were degenerated in wsll compared with wild type. Genetic analysis showed that the wsll was controlled by a single recessive gene. Molecular mapping of the wsll was performed using an F2 population derived from wsll/Nanjing 11. The wsll was finally mapped on the telomere region of chromosome 9 and positioned between simple sequence repeat markers RM23742 and RM23759 which are separated by approximately 486.5 kb. The results may facilitate map-based cloning of wsll and understanding of the molecular mechanism of the regulation of leaf-color by WSL1 in rice.

Preliminary Study on the Mechanism of Flower Color Variation in White Mutants of Anthurium andeaeanum

[Objectives] This study was conducted to explore the physiological mechanism of flower color variation in the white mutants of Anthurium andeaeanum. [Methods] The seven white mutants of 'Alabama' and 'Turenza' were used as materials to analyze the pigment types, flavonoid types and content and anthocyanin content in the wild type and mutants. [Results] The white spathe mainly contained flavonoids, flavonols, dihydroflavonols and dihydroflavonols; the white mutants of 'Alabama' had a higher total flavonoid content than the wild type, while the white mutants of 'Turenza' showed an opposite trend; and the spathe of the wild type had the highest anthocyanin content, and the pink part of the two-color mutant or the spathe of the binary color mutant contained trace anthocyanins, while no anthocyanins were detected in the white part of the mutants. [Conclusions] The main cause of the white mutants of A. andeaeanum is related to anthocyanin metabolism.

Heredity and gene mapping of a novel white stripe leaf mutant in wheat

Spotted leaf(spl)mutant is a type of leaf lesion mimic mutants in plants.We obtained some lesion mimic mutants from ethyl methane sulfonate(EMS)-mutagenized wheat(Triticum aestivum L.)cultivar Guomai 301(wild type,WT),and one of them was named as white stripe leaf(wsl)mutant because of the white stripes on its leaves.Here we report the heredity and gene mapping of this novel wheat mutant wsl.There are many small scattered white stripes on the leaves of wsl throughout its whole growth period.As the plants grew,the white stripes became more severe and the necrotic area expanded.The mutant wsl grew only weakly before the jointing stage and gradually recovered after jointing.The length and width of the flag leaf,spike number per plant and thousand-grain weight of wsl were significantly lower than those of the WT.Genetic analysis indicated that the trait of white stripe leaf was controlled by a recessive gene locus,named as wsl,which was mapped on the short arm of chromosome 6 B by SSR marker assay.Four SSR markers in the F2 population of wsl×CS were linked to wsl in the order of Xgpw1079–Xwmc104–Xgwm508-wsl–Xgpw7651 at 7.1,5.2,8.7,and 4.4 c M,respectively and three SSR markers in the F2 population of wsl×Jimai 22 were linked to wsl in the order of Xgwm508–Xwmc494–Xgwm518-wsl at 3.5,1.6 and 8.2 c M,respectively.In comparison to the reference genome sequence of Chinese Spring(CS),wsl is located in a 91-Mb region from 88 Mb(Xgwm518)to 179 Mb(Xgpw7651)on chromosome 6 BS.Mutant wsl is a novel germplasm for studying the molecular mechanism of wheat leaf development.

Analysis of Variations in White-Belly and White-Core Rice Kernels Within a Panicle and the Effect of Panicle Type

This study aims to investigate the variation in occurrence of white-belly rice kernel（WBRK） and white-core rice kernel（WCRK） among different positions within a panicle. Twenty-four M4 mutants involved in four panicle types, namely the compact, intermediate, loose, and chicken foot panicle were used. They derived from a japonica rice cultivar Wuyujing 3. Considerable differences in morphological characters existed among the four types of panicle, especially in panicle length, the secondary branch number and ratio of grain number to total branch length. Marked differences were found in WBRK and WCRK among different positions within a panicle for all types of panicle. In general, grains located on the primary rachis and top rachis branches had higher WBRK and WCRK percentage than those on the secondary rachis and bottom rachis branches. WCRK exhibited larger variation among grain positions than WBRK did. Moreover, there was a significant difference in WCRK/WBRK among grain positions within a panicle, with primary rachis and top rachis branches having higher values than the secondary and bottom rachis. In addition, panicle type showed no significant effect on the pattern of WBRK and WCRK occurrence within a panicle. The results indicated the difference in mechanism of WBRK and WCRK formation in grain position within a panicle, and are valuable for breeding and agronomic practices aimed at lowering chalky grain rate.

两个新的水稻叶色突变体形态结构与遗传定位研究

【目的】对2个新的水稻叶色突变体进行形态结构与遗传分析,并且初步定位这2个突变基因。【方法】在水稻育种材料中分别发现了一株白色条纹叶突变体和一株黄叶突变体,经多代自交已形成稳定的突变系。对突变体的主要形态特征与叶绿素组分等进行分析,观察叶绿体的超微结构,并以这2个突变系杂交产生的F2群体作为定位群体,应用SSR标记对突变基因进行初定位。【结果】与其野生型相比,白色条纹叶突变体的单株穗数减少12.86%,生育期延长11.27%,黄色叶突变体的株高降低31.08%,千粒重减少14.55%,生育期延长17.86%,并且2种突变体的叶绿素含量都显著低于其野生型。电镜观察结果表明:2种突变体的类囊体结构异常,与野生型水稻相比,黄色叶突变体的类囊体片层数变少,白色条纹叶中条纹部分的类囊体片层结构几乎消失,正常绿色部分的类囊体结构没有变化。遗传分析表明:这2种突变性状均受1对隐性核基因控制,位于不同染色体上,将突变基因暂时命名为st9(t)(stripe)、chl12(t)(chlorophyll-deficit)。将st9(t)定位到第一染色体短臂最末端,与分子标记RM1331相距9.6cM,且与标记RM3252等共分离;将chl12(t)定位到第三染色体短臂,与分子标记RM411、RM8208之间的遗传距离分别是1.2、5.1cM。【结论】发现了2个叶色突变新基因,为下一步的基因克隆与功能分析奠定了基础。

一个水稻苗期白条纹叶及抽穗期白穗突变体的鉴定和基因定位

从粳稻中花11组培后代中发现了一个苗期白条纹,抽穗期白穗的突变体。该突变体表现为1叶期叶全白,2叶期从新叶叶尖开始沿叶脉逐渐转绿,至成株期完全变绿,抽穗后内外颖表现为白色,穗轴和小枝梗表现为绿色,成熟后颖壳转黄。根据基因定位结果,将该突变体定名为wslwp(white striped leaf and white panicle)。与野生型相比,wslwp突变体2叶期及抽穗期叶片的叶绿素含量、类胡萝卜素含量及结实率均显著降低。遗传分析表明,该突变表型受1对隐性核基因控制,非T-DNA插入引起。为了克隆WSLWP基因,利用wslwp突变体与籼稻品种龙特甫B杂交获得的F2分离群体进行基因定位,首先将该基因定位于水稻第7染色体上的SSR标记RM5711与RM6574之间。随后,利用已有的SSR标记和开发的STS标记,进一步将该基因定位在STS7-63和STS7-65之间,物理距离约为87kb。

谷子条纹叶突变体wsl2的鉴定及候选基因分析

谷子叶色突变体是探究叶绿体发育机制和C4光能利用率的理想材料之一。为了研究谷子叶色突变的分子机制,从谷子主推品种长农35号的甲基磺酸乙酯(EMS)诱变库中筛选鉴定到一个苗期条纹叶突变体wsl2,通过表型鉴定、遗传背景检测和遗传分析,同时利用MutMap方法快速精细定位突变基因,并根据突变位点开发共分离分子标记等方面对该突变体进行研究。结果表明,wsl2在苗期表现为条纹叶表型,但从拔节期开始恢复为正常叶片表型;wsl2与野生型遗传背景相同且wsl2受一个隐性核基因控制;MutMap精细定位的关联区间内包含9个非同义突变基因,其中,Seita.9G561800是一个编码与叶绿体相关的PsbP蛋白基因,含有6个外显子和5个内含子,在第1外显子77 bp处发生G/T碱基突变,导致一个精氨酸(R)突变成亮氨酸(L)。根据突变碱基设计了dCAPS标记MRI498-1(Cac8Ⅰ)和共分离标记MRI501-3,进一步验证了wsl2突变体的候选基因突变位点。研究鉴定了一个新的条纹叶突变体wsl2,对PsbP基因光合作用反应机制的进一步研究奠定了理论基础,丰富了谷子叶色突变体资源,同时验证了MutMap方法克隆谷子突变基因的有效性。

水稻条白叶和白穗突变基因St-wp的遗传分析与精细定位

为研究叶绿体的差异性发育,本文通过60Co-γ诱变籼稻93-11筛选获得条白叶片和白穗突变体。经遗传分析表明,该突变性状受单隐性核基因控制,暂命名为St-wp(stripe white leaf and white panicle)。突变基因St-wp被精细定位于第6染色体标记d CAMPs620和In Del620之间,物理距离为9.2kb,此区间内包含3个候选基因。测序对比发现,突变体基因组的核糖核苷二磷酸还原酶小亚基(ribonucleoside-diphosphate reductase small chain)编码区第308碱基由A变为T,导致谷氨酸突变为缬氨酸。该基因与已报道的水稻白条纹叶基因St1和Gws等位,但突变体st1和gws均未表现出白穗性状。本研究可为叶绿体组织差异性发育的深入研究提供依据。

水稻白条纹叶Gws基因的精细定位与遗传分析

叶色突变是一类十分明显的性状突变,在高等植物的叶绿素合成、叶绿体结构、功能、遗传、分化与发育等基础研究中均具有重要意义。到目前为止,已鉴定多个重要的水稻功能基因,据不完全统计,水稻中至少已定位了79个叶色突变位点,并已成功克隆出多个叶色相关基因,其中OsCHLH、OsCAO1、OsCAO2、chlorina1、chlorina9、ygl等直接参与编码叶绿素合成,其余基因均参与叶绿体发育调控。在日本晴(Nipponbare)T-DNA插入突变体库中筛选到一份对温度敏感的白条纹突变体gws(green-white-stripe),遗传分析表明它来自组织培养过程中的单隐性基因突变。利用gws与培矮64杂交组合的F2代群体,将Gws精细定位于第6染色体标记InDel15和InDel16之间,物理距离为73kb,此区间内包含13个基因。基因组序列分析发现,突变体在核糖核苷二磷酸还原酶小亚基(ribonucleoside-diphosphate reductase small chain,RNRS1)编码区第314～315碱基发生缺失,第316～317碱基由GC变为TT,导致该基因阅读框移码突变,蛋白质翻译提前终止。该基因是已经报道的水稻白条纹叶基因St1(Stripe1)的等位基因,gws突变体较st1突变体的白条纹出现早且明显,gws白条纹表型出现在第2片叶之后,而st1的白条纹表型仅出现在第4或5片叶之后。

家蚕白卵突变新系BT924的遗传学研究

新的家蚕白色卵突变系BT924是由蓖麻蚕DNA导入家蚕品种苏学5诱导获得。性状特征 :滞育卵当年白色 ,越年后呈浅黄褐色 ;蛾区内及区间卵色略有变异 ,幼虫皮肤低度透明 ,成虫复眼黑色。采用家蚕卵色正常型 (黑卵 )和突变型红色卵 (re)、桃红眼白卵 (pe)、第2白卵 (w -2)、第3白卵 (w-3)及BH863油蚕白卵 (w -3bh)与之杂交 ,进行遗传分析 ,结果表明 ,BT924白卵及其油蚕性状由隐性单基因控制 ,普通遗传 ,基因座与w-3相同 ,即 :10 -19.6。命名为 :whiteeggBT924 ,基因符号 :w -3bt。w -3bt对re表现上位作用。同时发现家蚕基因库保存的桃红眼白卵 (pe)标记基因系pe000同时持有红色卵 (re)基因 ,其卵色基因型为repe/repe。

水稻白色中脉Oswm2的遗传分析与分子标记定位

从T-DNA突变体库中获得一份以中花11为遗传背景的白色中脉突变体。该突变体剑叶以下叶片的中下部中脉表现为白色,白色中脉附近的叶色微黄,并且伴随株高等农艺性状的改变,暂时将其定名为Oswm2(Oryza sativa white midrib2)。遗传分析表明该突变性状受一对隐性单基因控制,以Oswm2和粳稻02428杂交的F2分离群体作为定位群体,将OsWM2基因定位在水稻第7染色体的SSR标记RM21478和RM418之间,遗传距离分别为8.7和15.9cM。

水稻白条纹突变体st13的表型分析及基因定位

【目的】叶色突变相关基因鉴定和克隆有助于研究光合作用,补充并完善叶绿体发育机理和色素合成代谢途径,为开展水稻的高光效育种提供理论依据。【方法】从粳稻品种Dongjin的组培后代中分离出一个白条纹突变体st13,成熟期测定野生型和st13的主要农艺性状,苗期测定色素含量并观察叶绿体的超微结构;将st13和Dongjin进行正反交,观察F_1植株表型,并对F_2表型分离进行卡方检验,对st13进行遗传分析;利用st13×南京11(籼稻品种)的F_2和F_(2:3)群体,对st13突变基因定位;采用qPCR分析叶绿体发育和叶绿素合成相关基因在st13与野生型相对表达量。【结果】与野生型Dongjin相比,该突变体的株高、单株有效穗数、穗长、结实率和千粒重等主要农艺性状显著下降。苗期的色素含量降低,分蘖期无差异。突变体的叶绿体中既有含丰富的类囊体膜结构的正常叶绿体,也存在无类囊体结构的叶绿体。遗传分析和基因定位结果表明,st13的突变表型受1对隐性核基因控制,突变基因位于第3条染色体长臂InDel(Insertion-Deletion)标记I3-21和I3-22之间。进一步在这两个标记之间设计了6对InDel标记,最终将基因定位在94kb区间内,此区间共有8个候选基因。【结论】这8个候选基因中,有5个假定的蛋白,其他三个都是有功能注释的蛋白,而这三个蛋白在水稻中均未见报道,因此,st13突变是由一个新的叶色基因突变引起的;同时st13中叶绿体发育、叶绿素合成和光合系统相关基因的表达也发生了显著改变,推测ST13可能是调控叶绿体发育的关键基因。

水稻白色中脉Oswm突变体的遗传分析与基因定位

通过对粳稻9522γ射线诱变,从M2中筛选出1株带有白色中脉的隐性单位点突变的突变体,定名为Oswm(wm=white midrib)。Oswm叶片的近轴面中脉呈现白色,其他性状无明显异常。透射电镜观察结果表明,Oswm叶片位于白色中脉部位的叶绿体不能正常发育。为克隆OsWM基因,用Oswm突变体和籼稻广陆矮4号杂交的F2分离群体作为基因定位群体,通过图位克隆方法,首先将OsWM位点初步定位在水稻4号染色体上的SSR分子标记RM5503和RM2578之间。为了精细定位OsWM位点,在RM5503和RM2578之间发展了12个有多态性的InDel分子标记。最终将OsWM基因座位定位在CH413和CH415之间,遗传距离均为0.3 cM,物理距离约为122 kb。这为克隆OsWM基因以及研究叶绿体发育奠定了基础。

花生辐射突变体质量性状遗传

研究了用Gamma射线辐照花生产生的叶片白叶脉、叶较小突变体后代的遗传。结果表明,叶片白叶脉、叶片较小突变体后代分离出3种表现型:①所有性状与辐照前原品种相同;②所有性状与叶片白叶脉、叶较小突变体相同;③叶片白叶脉、叶极小、植株极矮、不结果。相应3种表现型的分离比例为1∶2∶1。认为白叶脉、叶片大小和植株高度是由同一基因位点控制的。高株对极矮株为显性,分离比例为3∶1;白叶脉对黄叶脉是显性,分离比例为3∶1;叶片大小是不完全显性效应,分离比例为1∶2∶1。叶片叶绿素含量与白叶脉无关,但与株高有关。

γ射线诱变烟草花药培养的突变体

本研究利用^(60)Coγ射线辐照烟草单核靠边期的花药,诱导培养突变体。结果表明,1kR左右的γ射线对花粉的出苗率有促进效应;3kR时,花药出苗时间延长,出苗花药率和花药产苗率明显降低,视为半致死剂量;6kR时,虽有部分花药可以出苗,但花药产苗率极低。诱变处理当代出现白花突变体,其后代的品质比亲本品种有明显改善,但抗病力下降。经试验,该突变系在生产上有实用价值。

两系水稻不育系白色中脉标记的诱发与特性

为开发可监控两系杂交水稻种子纯度的全新标记,通过60Co-γ辐照两系不育系Y58S干种子,筛选获得白色中脉、转绿型白化叶色、紫叶斑点、黄色、淡绿色与条纹白色等多种类型叶色突变体。与其他叶色突变体比较,突变体wml-1的白色中脉突变性状全生育期稳定,且仅在叶片正面的中脉部分表达,不影响苗高和主要农艺性状,配合力和不育特性也与野生型不育系相类似。遗传分析表明,叶片携带白色中脉突变性状受一对隐性基因控制。本研究结果表明,叶片携带白色中脉突变可以作为一种更理想的标记性状,对发展直观方便辅助去杂和省时节本鉴定种子纯度新技术具有重要意义。

肿瘤坏死因子新型免疫抑制剂的构建、表达和鉴定

目的 用鸡卵清溶菌酶(Hen egg-white lysozyme,HEL)T辅助细胞表位序列替换hTNF-α3’末端序列,构建和表达hTNF-α新型免疫抑制剂。方法 将重组的hTNF-α HEL克隆、表达、纯化后进行初步的生物学活性鉴定。结果 DNA测序分析表明,重组的hTNF-α HEL3’末端序列与设计序列完全相同。将其插入pBV220表达载体中,重组菌经42℃诱导4h做SDSPAGE分析,结果显示该免疫抑制剂获得了表达,M_r为17000,其表达量为菌体总蛋白量的30％。Western blot结果证实,该表达蛋白可与抗TNF-α抗体产生免疫反应。对该表达蛋白进行了阴离子交换柱纯化,获得的重组蛋白的纯度可达95％以上。对该蛋白的体外杀伤活性检测表明,该蛋白已完全丧失了TNF-α的体外杀伤活性。结论 上述实验结果证明,TNF-α免疫抑制剂的构建获得了成功,该免疫抑制剂既保持了与TNF-α抗体结合的能力又失去了TNF-α的杀伤活性,为其下一步治疗作用的研究奠定了基础。

家蚕第三白卵基因座的突变新成员ω-3~c

西南大学家蚕基因库保存的我国家蚕地方品种“三眠白卵”(编号19-340),其卵色为浅褐色白卵,幼虫低度油蚕,成虫复眼为黑色。采用卵色正常型黑卵系统,白卵标志基因w-2、w-3等的遗传系统与其进行杂交,对19-340进行了系统的遗传分析,结果表明该浅褐色白卵为家蚕第三白卵(w-3:10-19．6)基因的等位点突变。将其命名为chi- nese white egg 3,基因符号为w-3°。首次从我国家蚕地方种中发现第3白卵基因座自然突变。

油菜乳白花突变体的获得及后代遗传表现

对油菜品系优3进行了N+诱变处理研究,结果表明:N+诱变处理后,油菜品系优3 M2代产生1株乳白花突变体(正常黄花突变为乳白色花),自交后M3代表现白花∶乳白花∶黄花为1∶2∶1的分离比;用白花个体测交,后代表现白花∶乳白花为1∶1的分离比;用黄花个体测交,后代表现乳白花∶黄花为1∶1的分离比,表明油菜白花性状和黄花性状均受一对纯合基因控制,白花对黄花为不完全显性遗传。