水稻微效恢复基因排除方法及效果

前言 不少研究者认为,野败型不育系的恢保关系由一对或二对主基因控制[1·2·3]。然而,我们在育种实践中还发现,相当多的水稻品种除含有恢复基因或保持基因外,还含有另一种基因,即微效恢复基因[4、5]。国内外几靠筛选保持系转育不育系者,多因这种基因的效应,往往出现育性不稳定     

水稻光温敏核不育系B06S不育基因的遗传研究

利用混合分布理论对水稻新资源光温敏核不育系B06S不育性状的主基因进行了分析,结果表明：B06S受一对主效核基因控制,且该基因遗传效应较大。     

利用极大似然法分析珍汕97不育系恢复性的遗传

利用极大似然法和ＥＭ算法对野败型杂交籼稻恢复性的主基因进行了探讨。结果表明，恢复性由两对主基因控制，两对恢复基因间表现显性上位性互作，两对基因的作用存在强弱之分，强恢复基因的加性效应是弱基因的２倍。     

水稻质核互作雄性不育系的微效恢复基因定位和排除方法研究

以232个协青早A/B456///协青早A/B456∥B456植株组成的分离群体为材料,调查花粉可育率和自交结实率,并采用121个在染色体上分布比较均匀的SSR多态性标记进行QTL检测。发现22个SSR标记分别与10个花粉育性位点连锁,分布于第2,5,6,8,10,12染色体上;28个标记分别与16个小穗育性位点连锁,分布于第1,2,4,5,6,8,10和11染色体上;13个标记同时与花粉育性和小穗育性连锁,小穗育性与花粉育性QTL差异是花粉可育度和自交结实率不平行性的遗传基础。各可育位点对花粉育性和小穗育性的提高效应比较小,为微效基因,但每个花粉育性位点的存在都可导致不育系败育不彻底。协青早A中发现1个花粉可育位点Pf5-1,与分子标记Bm55和Rm13紧密连锁,进行分子标记辅助选择,可能排除协青早A的微效恢复基因(可育位点),达到完全不育。协青早A存在8个小穗育性位点,能够提高自交结实率,有助于杂种F1结实率的提高,有利于提高不育系的可恢复性。多数微效恢复基因显示为部分隐性或隐性,是水稻质核互作雄性不育系选育难的重要原因。采用不育系/拟用亲本∥保持系/拟用亲本的方式,观察杂种育性分离,可对拟用亲本的微效恢复基因有所了解,用保持系/部分保持系∥保持系的方式可提高微效恢复基因排除的效率。     

光温敏不育水稻不育性表达不稳定的遗传机制与原因综述

光温敏不育系不育性表达不稳定是近年来两系杂交水稻研究和应用中遇到的一大难题。为寻求克服这一难题的有效途径和方法，对不育性表达不稳定的遗传机制及其产生原因进行深入分析和探讨是十分必要的。界定了不育性表达不稳定的含义，综述了水稻光温敏不育系育性表达的种种复杂表现、不育起点温度漂变现象及其克服办法，着重论述了光温敏不育系不育性表达不稳定的遗传机制及原因。认为导致不育的起点温度受微效多基因控制是光温敏不育系不育性表达不稳定的遗传机制，不育起点温度上的遗传基础不纯或遗传杂合性是导致不育性表达不稳定的内在原因，并提出在育种上应充分考虑不育性表达的数量性状特征，采取花培育种途径或在杂交育种中采用系谱法和混合法相结合的后代选择方法，以达到选育不育性表达稳定的光温敏不育系的目的。     

籼型三系不育系选育的研究现状与创新思路

自２０世纪７０年代初,我国籼型杂交水稻实现三系配套以来,由于其强大的杂种优势与可操作性,在全国乃至世界得到迅速推广,为我国粮食的大幅度增产,解决１２亿人口的温饱问题立下了奇功,被称为农业上的“第二次绿色革命”。然而随着人民物质生活水平的日益提高以及下世纪我国人口高峰的临近,必将对稻米的需求总量、品质和食用卫生提出更高的要求。目前籼型三系杂交稻当家组合的不育系珍汕９７Ａ和威２０Ａ持续大面积使用了２０余年,种性逐步退化,丰产性变劣;开花习性差;柱头短小而不发达,外露率低;繁殖制种受温、湿度及光照条件…     

三系不育系龙特甫A的遗传改良效果

龙特甫Ａ具有异交率高,杂种优势强,但不育性不稳定的特性。利用珍汕９７Ｂ和地谷Ｂ对其进行遗传改良,育成不育性稳定性好,而又基本上保留了龙特甫Ａ的高异交和高配合力优点的新不育系Ｔ５５Ａ。用Ｔ５５Ａ配制的杂交组合Ｔ优５５６３和Ｔ优５５３７,在１９９９年晚稻省区试中,产量居Ｂ组的第１位和第３位,均比对照汕优６３增产,达极显著水平。     

水稻优质迟熟三系不育系六福 A 的选育及应用

介绍了六福A的选育过程,阐述了六福A的农艺性状、育性表现、开花习性、稻米品质、综合抗性、配合力等特征特性.六福A具有败育彻底,育性稳定,开花习性好,异交结实率较高,易于繁殖制种,米质优,可恢复性好,配合力强,所配组合熟期适宜等应用优势.     

温敏核不育基因在籼型三系遗传背景下的育性表达

用3个温敏核不育系培矮64S、6311S和360S与7个籼型质核互作型水稻雄性不育系及相应的保持系、3个恢复系配组,观察了51个组合的F1、19个F2及6个BC1的育性表现。结果表明：培矮64S温敏核不育性状由2对隐性基因控制,具有对质核互作型雄性不育系育性的强恢复基因;6311S温敏核不育性状由1对隐性基因控制,同时具有1对弱恢复基因;360S温敏核不育性状由1对隐性基因控制,但没有恢复基因。进一步利用4个细胞质雄性不育系/6311S组合F2群体中4个温敏核不育株与5个细胞质雄性不育系CMS配组,研究了杂交F1的育性,表明在可育细胞质背景下,三系恢复基因对温敏核不育基因的表达没有影响;在不育细胞质背景下,三系恢复基因是温敏核不育基因表达的关键。由此提出了选育不育细胞质背景的光温敏核不育系和温敏核不育背景的质核互作型不育系的策略。     

一份水稻OsWOX3B基因敲除突变体的鉴定

[目的]水稻OsWOX3B基因调控叶片形态和表皮毛发育,根据表型被命名为LSY1、DEP、NUDA和GLR1等.深入了解OsWOX3B基因对水稻发育调控的功能具有重要意义.[方法]利用CRISPR/Cas9基因编辑技术对籼稻品种R401的OsWOX3B进行基因敲除.对所获材料进行突变位点分析和表型分析,同时进行相关基因...     

利用同工酶标记水稻亲本遗传差异及其在杂交水稻育种中的利用

利用淀粉凝胶和聚丙烯酰胺凝胶电泳显示的同工酶差异，分析17个杂交水稻亲本、3个新株型株系和22个光壳稻、爪哇稻品种的遗传差异，研究光壳稻和爪哇稻及其与温带粳稻之间的关系，探索同工酶标记水稻亲本遗传差异在杂交稻育种中利用的可能性。在本研究中，8个同工酶18个多态性位点至少在2个基因型间存在差异。每个具有多态性的酶谱带分别以1和0记录存在与否，由同工酶数据计算的Nei’s遗传距离创建聚类树状图。聚类分析结果表明，籼稻和粳稻容易被分开，普通粳稻与光壳稻、爪哇稻混合聚在一起；光壳稻与爪哇稻之间的遗传距离要比它们与普通粳稻之间的遗传距离小。利用光壳稻、爪哇稻选育不同生态群方向的恢复系和不育系，已配组育成了强优势的杂交稻组合。     

不同生态环境下水稻穗部性状QTL鉴定

【目的】发掘与产量相关的穗粒性状QTL对进一步克隆和利用高产基因具有重要意义。【方法】以超级粳稻龙稻5号和典型高产籼稻中优早8号杂交衍生的重组自交系群体为试材,在4种环境下对穗部性状进行比较和QTL分析。【结果】共检测到63个穗部性状QTL,分布于除第9染色体外的11条染色体上。在4个环境下分别检测到27、27、18和35个QTL。其中,16个QTL能在2个环境下被检测到,12个在3个以上环境下稳定表达,分别占QTL总数的25.40%和19.05%;第1、3、4和5染色体的多效QTL簇能在不同环境下稳定表达,对穗部性状具有明显的调控作用。【结论】第3染色体STS3.3-STS3.6区间的qSNP3、第4染色体RM5688-RM1359区间的qSNP4.1是2个新的稳定表达的多效性QTL簇。此外,上位性效应是调控穗部性状的重要组分。     

Correlation between Chloroplast Ultrastructure and Chlorophyll Fluorescence Characteristics in the Leaves of Rice (Oryza sativa L.) Grown under Salinity

Abstract

The seedlings of Oryza sativa L. cv. Nipponbare grown by hydroponic culture for 3 wks were treated with 75, 100, 150 and 200 mM NaCl for 14, 14, 6 and 3 days, respectively, and examined for chloroplast ultrastructure in the region where chlorophyll fluorescence had been recorded. NaCl treatment decreased the ratio of variable to maximum chlorophyll fluorescence yield (F_v/F_m) and caused swelling of thylakoids. The swelling of thylakoids was quantified by the percentage of the length of swollen thylakoids to the total length of thylakoids. This value was increased with increasing NaCl concentration. Although F_v/F_m decreased at all concentrations of NaCl, the minimal fluorescence yield F₀ was not increased by the treatment with 75 or 100 mM NaCl. The percentage of the length of swelling was low at 75 and 100 mM NaCl. On the other hand, F₀ increased and the swelling of thylakoids was prominent with 150 and 200 mM NaCl treatment. These results suggest that the decrease in F_v/F_m due to the increase in F₀ under salt stress correlates with the ultrastructural damage. The decrease in F_v/F_m due to the increase in F₀ is expected to be useful as an indicator to evaluate the damage in chloroplasts, especially in thylakoid membranes, under salinity.     

水稻穗顶部小穗退化突变体paa1-2的表型与等位基因序列分析

水稻穗顶部小穗退化在水稻生产中普遍存在,严重影响了水稻产量。本文对水稻穗顶部小穗退化突变体paa1-2进行表型观察,同时测序分析突变体paa1-2中已报道的TUTOU1和PAA1基因序列。结果表明,突变体paa1-2穗顶部退化表型是在幼穗发育6期后产生的。突变体paa1-2和野生型的TUTOU1基因序列一致,然而其PAA1基因存在突变,在第1512~1515 bp处存在4个碱基缺失,导致基因移码突变并使得蛋白翻译提前终止,PAA1-2可能是已报道PAA1基因的新等位突变基因。     

Genotypic Variation of Stomatal Conductance in Relation to Stomatal Density and Length in Rice (Oryza sativa L.)

Abstract

Stomatal conductance (g_s) is an important trait responsible for the genotypic difference in gas diffusion for photosynthesis and transpiration in rice (Oryza sativa L.). We measured g_s, stomatal density and stomatal length (guard-cell length) at two weeks before heading for 64 accessions from a rice diversity research set of germplasm (RDRS) and for three high-yielding cultivars (HYC) under field conditions. Considerable variations in g_s, and stomatal length were observed among varieties in RDRS, and it was considered that RDRS covers the species diversity of the stomatal characteristics in rice. When it was compared among the varieties with similar plant earliness, g_s was higher in HYC than in most varieties of RDRS. Stomatal density did not correlate with g_s, and there was a negative correlation between stomatal density and stomatal length. However, noticeable variance existed in the latter relation, where HYC exhibited a higher stomatal density and slightly shorter stomatal length than RDRS. High g_s in HYC is attributable to their high stomatal density and moderate specific stomatal conductance (g_s / stomatal density) while the high-g_s varieties in RDRS tended to have a lower stomatal density and higher specific stomatal conductance. Stomatal length is related to specific stomatal conductance, but there are remarkable differences between these traits. Specific stomatal conductance in HYC has not reached the upper limit for their stomatal size, which raises a possibility of further improvement of HYC in g_s.     

Ammonia Emission from Leaves of Different Rice (Oryza sativa L.) Cultivars

Abstract

NH₃ emission from leaves of three rice (Oryza sativa L.) cultivars, Akenohoshi, Shirobeniya and Kasalath, was examined using a simple open chamber system.　In the three cultivars, NH₃ emission rate (AER) and NH₄⁺ content of leaves decreased with decreasing NH₄⁺ concentration in the root medium, but these values differed significantly with the cultivar. In the daytime, AER, NH₄⁺ content and glutamine synthetase (GS) activity in leaves changed similarly with maximum values around midday. Akenohoshi showed significantly lower AER and NH₄⁺ content but higher GS activity than Kasalath. The difference in AER among the rice cultivars may be related to the activity of GS involved in photorespiratory NH₃ recycling. Akenohoshi can be a breeding material useful for improving N recycling.     

Identification of Casparian Bands in the Mesocotyl and Lower Internodes of Rice (Oryza sativa L.) Seedlings Using Fluorescence Microscopy

Abstract

The mesocotyl and lower internodes of seedlings are underground organs that play a possible role in water absorption and transport. The aim of this study is to reexamine and understand further the anatomy and morphology of mesocotyls and lower internodes in rice, especially in terms of the existence of Casparian bands. Anatomical structures of mesocotyl and lower internodes tissue of rice seedlings were observed by light and fluorescence microscopy. The rice mesocotyl had two central cylinders, one is large and the other small, in the cross section. Casparian bands were observed in both the endodermis and exodermis of the mesocotyl, and also in the endodermis of the first internode. Furthermore, some bundles with intermediate xylem differentiation were observed between the exarch and endarch arrangement in the first internodes. Casparian bands were identified in the radial walls of cells surrounding each of these bundles. The second internode is quite similar to that of upper internodes in adult plants with respect to internal structure; scattered vascular bundles were seen as in monocotyledons. In the second internode, Casparian bands were seen in the radial cell walls of the bundle sheaths in each vascular bundle. Unlike the mesocotyl, Casparian bands were not observed in the hypodermis of the first or second internodes. The results show that the histological features of the mesocotyl and lower internodes of rice seedlings widely differed. In addition, the present study provides anatomical evidence for the existence of Casparian bands in both the mesocotyl and lower internodes of rice seedlings.