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。     

温度对温敏核不育水稻eui突变体最上节间伸长的影响

以培矮64S为对照, 采用田间调查和人工温度处理方法研究了温度对温敏核不育水稻（Oryza sativa）eui突变体（双低培eS）最上节间伸长的影响。结果表明, 双低培eS穗颈伸出度与抽穗前12–17天（花粉母细胞形成期至减数分裂期）的日均温度呈显著负相关。在温度敏感期分别进行人工温度处理, 在18–26℃条件下穗颈伸出度为正值且不包颈; 在28℃条件下出现包颈现象。在可育温度（20℃）和不育温度（24℃）条件下, 双低培eS最上节间中GA1、IAA和ZR含量极显著地高于培矮64S, 而ABA含量则显著低于培矮64S, 最上节间中最内层薄壁细胞数目分别比培矮64S多1 177和823个, 细胞平均长度分别比培矮64S长23.2和16.7 μm。温敏核不育水稻eui突变体最上节间伸长是由于节间最内层薄壁细胞数目增多和细胞长度增加双重作用所致, 其中以细胞伸长为主, 且随着处理温度的升高, 最上节间最内层薄壁细胞数目减少, 细胞平均长度变短。eui基因还可能通过调节激素间的平衡来控制温敏核不育水稻eui突变体最上节间的伸长生长。     

8个籼型水稻环境敏感核不育系的育性转换特性研究

在武汉、贵阳（1997年）和三亚（1997－1998年）3个生态点,对8个籼型水稻（Oryza Sativa L.ssp.indica）环境敏感核不育系（2－2S、K1405S、F131S、2136S、Pei-Ai64S、1290S、GD－1S和N17S）进行分期播种试验,每期相隔10－15d,考察自交不育度的动态变化,结果表明,8个不育系在武汉的稳定不育期均长于30d,在遗阳的稳定不育期均短于30d,在三亚的稳定不育期均长于150d。8个不育系的育性表达均表现对温度敏感,但不同的不育系育性转换的敏感时期、敏感敏感期的长短和临界温度是不同的。2－2S和K1405S的敏感时期位于抽穗前的第18天至第9天,敏感期为7－10d,育性转换的临界温度为23.7－24.5℃。F131S的敏感时期位于抽穗前的第17天至第5天,敏感期为13d,育性转换的临界温度为24.3-24.7℃。2136S的敏感时期位于抽穗前的第24天至第11天,敏感期为7－13d,育性转换的临界温度分别为24.3-24.7℃、25.5-26.2℃、25.4-26.1℃和24.1-24.7℃。     

培矮64S中不育临界温度低的新株系筛选

在自然与控温条件下,研究了培矮６４Ｓ育性对温度反应的个体差异,从中筛选出１个不育临界温度低的新株系,即９６－５－２Ｓ．在此株系育性转换敏感期内,用２２℃恒温处理,结实率为０．０％;而用１８．５℃的冷水串灌处理,结实率为５７．６％     

温室冬繁水稻低温敏核不育系原种方法的初步研究

１９９５年１—５月,在广州利用玻璃温室加温冬繁籼型水稻低温敏核不育系培矮６４ｓ和ＧＤ－２ｓ原种．当不育系进入育性转换敏感期时,温室室温调控至日均温约２３℃,检查花粉育性和自然结实率,结果表明,培矮６４ｓ的结实率为５０．７％,单株产量平均为３．５ｇ．培矮６４ｓ原种温室冬繁的成功,为现有种量少、繁种难、提纯复壮株严格的低温敏核不育系加速世代扩大繁殖系数提供了一种可靠的途径．     

植物生长调节剂对水稻光敏核不育系培矮64S育性恢复的作用(简报)

一定剂量的CoCl2、IAA和2,4-D以及与GA3配合叶面喷施或根部水施后,水稻培矮64S的育性在不育条件下得到部分恢复。其中以浓度各为50mg／L的2,4-D和GA3配合进行根部水施效果最好自交结实率提高达7.9％。     

双低两用核不育水稻96-5-2S冷水灌溉繁殖技术研究

为解决临界温度双低两用核不育水稻96—5—2S繁殖困难的问题,利用地下水对其进行了冷水灌溉繁殖试验．结果表明,用不同温度的冷水从其雌雄蕊形成期(Ⅳ)至花粉内容物充实期(Ⅶ)连续灌溉15d。水深保持在18～22cm,其结实率与产量随灌溉水温升高而降低．当平均灌溉水温为18．5～19．8℃时。结实率可达40．5％～57．6％。产量可达3．30～4．35t·hm^-2;当平均灌溉水温为20．5～21．3℃时,结实率与产量锐减,分别为2．5％～10．4％与0．21～0．90t·hm^-2;当平均灌溉水温为22．3～23．5℃时。结实率与产量均为0．当灌溉水温(平均为19．8℃)与灌溉时期(Ⅳ～Ⅶ期)相同时,昼夜深灌(18～22cm)处理的结实率与产量极显著高于其昼夜浅灌(7～10cm)处理．当灌溉水温(平均为19．8℃)与灌溉水深(18～22cm)相同时,灌溉时间长(Ⅱ、Ⅲ～Ⅶ期,20～25d)、短(Ⅳ～Ⅶ期,15d)处理的结实率与产量无明显差异．用地下冷水灌溉可以繁殖临界温度双低两用核不育水稻96—5—2S。主要技术指标是灌溉水温18～20℃,灌溉时期为Ⅳ～Ⅶ期。灌溉水深为18～22cm．     

双低两用温敏核不育水稻低温条件下花粉发育的细胞学观察

双低两用温敏核不育水稻96－5－2S在11.31－20.19℃低温条件下,花粉母细胞形成、减数分裂和花粉后期发育均正常,最后形成充满淀粉的成熟花粉,而作对照的两用温敏不育水稻陆18S在相同低温条件下,除花粉母细胞形成早期发育正常外,花粉母细胞晚期、减数分裂期均有异常,败育主要发生在单核小孢子靠边期,没有形成成熟花粉,结果表明,96－5－2S桫胜殖期抗寒性强,低温生理障碍雄性不育临界温度低。     

籼型光敏核不育水稻育性可转换性的基因定位和基因互作研究

本研究以来源于农垦58S的灿型光敏核不育系培矮64S（短日条件下育性难转换）和8902S（短日条件下育性蝗转换）及其F1,F2群体为材料,通过短日不同光温和不同生态条件4种处理,利用RFLP分子标记研究了影响光敏偿育水稻在短日条件下的育性可转换性的遗传,基因定位和基因互作,主要结果表明：影响光敏不育水稻的育性可转换性表现为微效基因的作用,定位了7个控制光敏核不育水稻的育性可转换性QTL,即S2,S3a,S3b,S5,S8和S10,揭示了基因互作真实存在于光敏核不育水稻中,基因互作形式和互作类型对光敏核不育水稻的育性可转换性的影响表现多种多样,不同类型的基因互作所解释的遗传变异处于2．15％－10．07％之间。     

植物生长调节剂对水稻光敏核不育系培矮64S育性恢复的作用…

一定剂量的ＣｏＣｌ２,ＩＡＡ和２,４－Ｄ以及与ＧＡ３配合叶面喷施或根部水施后,水稻培矮６４Ｓ的育性在不育条件下得到部分恢复,其中以浓度各为５０ｍｇ／Ｌ的,２,４－Ｄ和ＧＡ３配合进行根部水施效果最好,自交结实率提高达７．９％。     

Effect of Growth Regulators and Chemicals on Pollen Sterility in TGMS Lines of Rice

Thermosensitive genic male sterility (TGMS) in rice is a widely adopted technique for successful hybrid rice production in Asia. TGMS lines remain male sterile when daily mean temperature is above the critical sterility temperature and are therefore used as female parents. The same line will remain fertile when mean temperature is below the critical sterility temperature. Achievement of 100% male sterility in TGMS lines is important for the successful utilization of TGMS lines as female parents in hybrid rice production. This study examined the external application of some growth regulators and chemicals and their effect on pollen sterility. Among the various treatments, ethrel (800 ppm), salicylic acid (600 ppm) and maleic hydrazide (0.2%) induced a significantly higher percentage of male sterility in the TGMS lines. The sprayed plants also showed higher total phenol accumulation in their flag leaves. The results suggest that it is possible to achieve 100% male sterility in TGMS lines with the external application of growth regulators and chemicals.     

Molecular mapping of two reverse photoperiod-sensitive genic male sterility genes (rpms1 and rpms2) in rice (Oryza sativa L.)

The reverse photoperiod-sensitive genic male sterility (PGMS) and thermo-sensitive genic male sterility (TGMS) lines have an opposite phenotype compared with normal PGMS and TGMS lines widely used by the two-line system in current hybrid rice seed production. Thus, the application of reverse PGMS and TGMS lines can compensate PGMS and TGMS lines in hybrid rice production. YiD1S is a reverse PGMS line, in which pollen fertility is mainly regulated by day-length, but also influenced by temperature. Genetic analysis indicated that male sterility of YiD1S was controlled by two recessive major genes. An F₂ population from a cross between YiD1S and 8528 was developed and used for molecular mapping of the two reverse PGMS genes which were first named rpms1 and rpms2. Both simple sequence repeat (SSR) markers and bulked segregant analysis (BSA) were used in this study. As a result, one reverse PGMS gene (rpms1) was mapped to the interval between SSR markers RM22980 (0.9 cM) and RM23017 (1.8 cM) on chromosome 8. Eight SSR markers, YDS818, RM22984, RM22986, RM22997, YDS816, RM23002, RM339 and YDS810 completely co-segregated with the rpms1 gene. Another reverse PGMS gene (rpms2) was mapped to the interval between SSR markers RM23898 (0.9 cM) and YDS926 (0.9 cM) on chromosome 9. The physical mapping information from publicly available resources shows that the rpms1 and rpms2 loci are located in a region of 998 and 68 kb, respectively. The analysis based on marker genotypes showed that the effect of rpms1 was slightly larger than that of rpms2 and that the two genes interacted in controlling male sterility. H. F. Peng, Z. F. Zhang and B. Wu contributed equally to this work.     

Comparative proteomics analysis reveals the mechanism of fertility alternation of thermosensitive genic male sterile rice lines under low temperature inducement

Thermosensitive genic male sterile (TGMS) rice line has made great economical contributions in rice production. However, the fertility of TGMS rice line during hybrid seed production is frequently influenced by low temperature, thus leading to its fertility/sterility alteration and hybrid seed production failure. To understand the mechanism of fertility alternation under low temperature inducement, the extracted proteins from young panicles of two TGMS rice lines at the fertility alternation sensitivity stage were analyzed by 2DE. Eighty‐three protein spots were found to be significantly changed in abundance, and identified by MALDI‐TOF‐TOF MS. The identified proteins were involved in 16 metabolic pathways and cellular processes. The young panicles of TGMS rice line Zhu 1S possessed the lower ROS‐scavenging, indole‐3‐acetic acid level, soluble protein, and sugar contents as well as the faster anther wall disintegration than those of TGMS rice line Zhun S. All these major differences might result in that the former is more stable in fertility than the latter. Based on the majority of the 83 identified proteins, together with microstructural, physiological, and biochemical results, a possible fertile alteration mechanism in the young panicles of TGMS rice line under low temperature inducement was proposed. Such a result will help us in breeding TGMS rice lines and production of hybrid seed.     

Photoperiod- and thermo-sensitive genic male sterility in rice are caused by a point mutation in a novel noncoding RNA that produces a small RNA

Photoperiod- and thermo-sensitive genic male sterility (PGMS and TGMS) are the core components for hybrid breeding in crops. Hybrid rice based on the two-line system using PGMS and TGMS lines has been successfully developed and applied widely in agriculture. However, the molecular mechanism underlying the control of PGMS and TGMS remains obscure. In this study, we mapped and cloned a major locus, p/tms12-1 (photo- or thermo-sensitive genic male sterility locus on chromosome 12), which confers PGMS in the japonica rice line Nongken 58S (NK58S) and TGMS in the indica rice line Peiai 64S (PA64S, derived from NK58S). A 2.4-kb DNA fragment containing the wild-type allele P/TMS12-1 was able to restore the pollen fertility of NK58S and PA64S plants in genetic complementation. P/TMS12-1 encodes a unique noncoding RNA, which produces a 21-nucleotide small RNA that we named osa-smR5864w. A substitution of C-to-G in p/tms12-1, the only polymorphism relative to P/TMS12-1, is present in the mutant small RNA, namely osa-smR5864m. Furthermore, overexpression of a 375-bp sequence of P/TMS12-1 in transgenic NK58S and PA64S plants also produced osa-smR5864w and restored pollen fertility. The small RNA was expressed preferentially in young panicles, but its expression was not markedly affected by different day lengths or temperatures. Our results reveal that the point mutation in p/tms12-1, which probably leads to a loss-of-function for osa-smR5864m, constitutes a common cause for PGMS and TGMS in the japonica and indica lines, respectively. Our findings thus suggest that this noncoding small RNA gene is an important regulator of male development controlled by cross-talk between the genetic networks and environmental conditions.     

Fine mapping of a gene for non-pollen type thermosensitive genic male sterility in rice (Oryza sativa L.)

The thermo-sensitive genic male sterility (TGMS) lines play a crucial role in two-line hybrid rice production. For a practical TGMS line, the stability of male sterility is one of the most important technical indicators. In this study, XianS, a spontaneous mutant with stable male sterility from an indica rice cultivar Xianhuangzhan, was classified as a non-pollen type TGMS line. The critical non-pollen sterility point temperature of XianS was determined as 27°C. Genetic analysis demonstrated that the non-pollen sterility in XianS was controlled by a single recessive gene. Using SSR markers and bulked segregant analysis, the TGMS gene in XianS was fine mapped to a 183 kb interval between RMAN81 and RMX21 on chromosome 2. Two markers, 4039-1 and RMX14 completely cosegregated with this gene. Allelism test indicated that the non-pollen phenotype in seven non-pollen type TGMS lines from different sources, XianS, AnnongS-1, Q523S, Q524S, N28S, G421S, and Q527S is caused by the same TGMS gene. Although the location of TGMS gene in XianS is close to the gene OsNAC6, a previously identified candidate gene of tms5 in AnnongS-1, the sequence of OsNAC6 and its promoter region was identical in TGMS line XianS, AnnongS-1, and wild-type Xianhuangzhan. These results suggest that the non-pollen type TGMS trait probably be controlled by the same TGMS gene in different TGMS rice lines, but its real candidate gene still need to be further studied and identified.     

Low temperature compensates for defective tapetum initiation to restore the fertility of the novel TGMS line ostms15

In rice breeding, thermosensitive genic male sterility (TGMS) lines based on the tms5 locus have been extensively employed. Here, we reported a novel rice TGMS line ostms15 (Oryza sativa ssp. japonica ZH11) which show male sterility under high temperature and fertility under low temperature. Field evaluation from 2018 to 2021 revealed that its sterility under high temperature is more stable than that of tms5 (ZH11), even with occasional low temperature periods, indicating its considerable value for rice breeding. OsTMS15 encodes an LRR-RLK protein MULTIPLE SPOROCYTE1 (MSP1) which was reported to interact with its ligand to initiate tapetum development for pollen formation. In ostms15, a point mutation from GTA (Val) to GAA (Glu) in its TIR motif of the LRR region led to the TGMS phenotype. Cellular observation and gene expression analysis showed that the tapetum is still present in ostms15, while its function was substantially impaired under high temperature. However, its tapetum function was restored under low temperature. The interaction between mOsTMS15 and its ligand was reduced while this interaction was partially restored under low temperature. Slow development was reported to be a general mechanism of P/TGMS fertility restoration. We propose that the recovered protein interaction together with slow development under low temperature compensates for the defective tapetum initiation, which further restores ostms15 fertility. We used base editing to create a number of TGMS lines with different base substitutions based on the OsTMS15 locus. This work may also facilitate the mechanistic investigation and breeding of other crops.     

Characterization and Use of Male Sterility in Hybrid Rice Breeding

The hybrid rice （Oryza sativa L.） breeding that was Initiated In China in the 1970s led to a great improvement in rice productivity. In general, It increases the grain yield by over 20% to the inbred rice varieties, and now hybrid rice has been widely introduced into Africa, Southern Asia and America. These hybrid varieties are generated through either three-line hybrid and two-line hybrid systems; the former is derived from cytoplasmic male sterility （CMS） and the latter derived from genlc male sterility （GMS）. There are three major types of CMS （HL, BT and WA） and two types of GMS （photoperlod-sensitlve （PGMS） and temperature-sensitive （TGMS））. The BT- and HL-type CMS genes are characterized as orf79 and orfH79, which are chimeric toxic genes derived from mltochondrial rearrangement. Rf3 for CMS-WA Is located on chromosome 1, while Rf1, Rf4, Rf5 and Rf6 correspond to CMS-BT, CMSoWA and CMS- HL, located on chromosome 10. The Rfl gene for BT-CMS has been cloned recently, and encodes a mltochondriatargeted PPR protein. PGMS Is thought to be controlled by two recessive loci on chromosomes 7 and 12, whereas nine recessive alleles have been identified for TGMS and mapped on different chromosomes. Attention Is still urgently needed to resolve the molecular complexity of male sterility to assist rice breeding.