温敏雄不育小麦花粉育性和结实率的观察

本文对温敏雄不育小麦 C4 9S的花粉育性和结实率做了观察。发现随着播期的延迟 ,C4 9S花粉育性和结实率由低向高 ,早播 (第一期 )不育 ,晚播 (第六期 )可育 ,肯定 C4 9S为一优异温敏材料。同穗不同部位小穗的花粉育性和结实率不同 ,上部 <中部 <下部 ,并且 C4 9S同一小穗不同位次小花的花粉育性和结实率也有差异。

Cloning of the APRT Gene from Rice and Analysis of Its Association with TGMS

Adenine phosphoribosyltransferase (APRT) is the major enzyme that converts adenine into adenosine-3'-phosphate (AMP). APRT-deficient mutant caused by APRT gene mutation results in the male sterility in Arabidopsis thaliana L. In order to confirm the existence of rice APRT gene and to investigate its association with thermo-sensitive genic male sterile (TGMS) phenotype of rice, a APRT gene was identified from BLAST search of the rice genome database using APRT gene sequences from other plant species as probes. Further, the gene was cloned from rice and named APRT(GenBank accession number AY238894) using the combination of bioinformatic and experimental approaches. The rice APRT was located in the 56 000 bp to 63 000 bp region of a rice bacterial artificial chromosome (BAC) clone (AL606604) on chromosome 4 and was deduced by software from the positive DNA clone. Its cDNA was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) using primers designed according to the sequence of the putative gene. The full-length cDNA was obtained by rapid amplification of cDNA ends (RACE) procedure and was sequenced. Open reading frame (ORF) analysis indicated that the rice APRT gene encodes a peptide of 212 amino acid residues, including seven exons and six introns. Using reverse position specific BLAST (RPS-BLAST), the APRT domain was identified in the polypeptide. The homology comparison demonstrated that the polypeptide exhibits 54.9%, 54.9%, 49.6% and 59.5% identity with that from Hordeum vulgare, Ttriticum aestivum, and A. thaliana (APRT types 1 and 2), respectively. Comparing the sequence of APRT gene from TGMS mutant lines 'Annong S-1' (Oryza sativa subsp. indica) with that from its corresponding wild type 'Annong F' (Oryza sativa. subsp. indica), we found that there are five single nucleotid polymorphism (SNP) sites in the gene of 'Annong S-1', which locate mainly in the second intron. However, the result of cDNA sequencing showed that these SNP sites do not damage the successful splicing of intron 2. Qualitative RT-PCR and Northern blot indicated that the gene tran-scription in the 'Annong S-1' young panicles that were verified to be the thermo-sensitive organ at the early stage of pollen fertility alternation is down-regulated by high temperature stress (28 V), which is the critical temperature causing 'Annong S-1' fertility conversion. These results revealed that the change of expression pattern of APRT in young particles of 'Annong S-1' in high temperature conditions is perhaps related to the TGMS of 'Annong S-1'.

Comparative Studies on the Changes of Microtubule Distribution and Reorganization During the Meiotic Stages of Development in Normal (IR36) and a Temperature/photoperiod Sensitive Male Sterile Line (Peiai 64S) of Rice ( Oryza sativa )

Changes in the pattern of organization of microtubules in the meiotic stages of development of pollen (i.e. from pre-meiotic interphase to more or less metaphase I) of a normal (IR36) and a temperature/photoperiod sensitive male sterile line (Peiai 64S) of rice were studied using immunofluorescence confocal microscopy. In IR36, from pre-meiotic interphase to metaphase I, the pattern of microtubule distribution in the meiocytes underwent a series of changes. Some new organizational patterns of microtubules (that have not been described before) were observed during microsporogenesis, including the existence of a broad band of perinuclear microtubules at the diakinesis stage of development. The pattern of microtubule distribution in the meiocytes of the male sterile line, Peiai 64S, was quite different front that seen in IR36. In Peiai 64S, the microtubules showed abnormal patterns of distribution from pre-meiotic interphase to metaphase I. For example the broad band of perinuclear microtubules seen at diakinesis in IR36 was much disorganized and loosened in Peiai 64S. The spindles formed were also very abnormal and different from the normal spindle. The appearance of abnormal microtubule distribution in the early stages of microsporogenesis may contribute to the malformation and ultimate abortion of pollen in Peiai 64S.

Investigation on the Sterility Changeover of Male Sterility Line CMS7311 in Heading Chinese Cabbage

Sterility changeover induced by low temperature in male sterility line CMS7311 of heading Chinese cabbage ( Brassica campestris L. ssp. penkinsis) was investigated under constant temperature, day/night alternating temperature in light-growth-incubator and outdoor natural day/night alternating temperature respectively. It showed that the sterility of CMS7311 has significant change with temperature. The constant temperature of 6 - 12 degreesC was suitable to induce the changeover of sterility (CGS) of CMS7311 ; the shortest treatment time for CGS induction at this temperature was 3 d. The significant value of sterility changeover of CMS7311 occurred at the constant temperature of 6 - 9 degreesC after treatment for 6 - 9 d. The intensity of CGS was stronger under constant temperature than under alternate temperature, but the shortest treatment time inducing CGS has no difference between them. When treated for 9 d under the day/night alternating temperature of 11/7 degreesC, its sterility could also turn to normal fertility (near to sterile grade I or zero). In normal condition, the interval from the end of temperature treatment to the beginning of CGS induction was 10 - 16 d. In the condition of natural day/night alternating temperature, the lower limit of temperature for effective CGS induction was at the daily mean temperature ( DMT) of 3. 5 - 6. 8 degreesC, and the shortest treatment time which could induce the sterility changeover was also longer than that under constant temperature, being 11d at DMT of 1.5 - 3.1 degreesC. In addition, for the apical dominance, the flower bud on the first lateral branch showed the CGS 8 - 10 d later than the flower bud on the main stem under the same temperature with the same days of treatment. The intensity of CGS of CMS7311 on the first lateral branch was also weaker than the flower bud on the main stem.

Studies on Thermo-sensitivity of Ningxia Hot Pepper Male Sterile Line

[Objective] This study was conducted to identify the thermo-sensitivity of the male sterile line （NYB） of Ningxia hot pepper. [Method] The pol en abortion rates of pepper male sterile line under artificial y control ed temperature condition and nature temperature condition were measured and compared. [Result] The pol en abortion was the sign of NYB male sterility. The pol en abortion rate changed little under different temperature conditions, while pol en amount greatly reduced at low temperature, indicating that NYB was genetical y stable in field. [Conclusion] The re-sults can provide some theoretical references for the application of NYB pepper male sterile line in breeding work.

Research Advances in Molecular Mechanism of Thermo-sensitive Genic Male Sterility in Plants

Thermo-sensitive genic male sterile （TGMS） lines have specific superiority in heterosis utilization of crops. So far, thermo-sensitive genic male sterile lines have been found in many plants and are widely used in two-line hybrid breeding. With the rapid development of molecular biology, the molecular nature of thermo-sensitive genic male sterility has been revealed, which lays the foundation for further devel- opment and utilization of thermo-sensitive genic male sterile lines. In this study, the molecular mechanisms of fertility conversion of plant thermo-sensitive genic male sterile lines were reviewed from gene molecular mapping and gene differential ex- pression, and the mechanisms of gene differential expression in thermo-sensitive genic male sterile lines were further discussed.

Studies on Breeding and Application of Thermo-sensitive Genie Male Sterile Line 402S in Brassica napus Ⅰ. Hie Breeding Procedure and Character of 402S

A new rapeseed TGMS line 402S has been bred through six years with seven generations by hybridization and systematic breeding.402S possesses the similar thermo-sensitive male sterility to its female parent Xiangyou 91S which performed fertile,partially sterile and sterile throughout the flowering stage,and resembles its male parent Zhongshuang 4 on agronomic traits.And 402S has the double-low (low erutic acid and low glucosinolate) quality like its original parents.

Differentially Expressed Genes Related to Fertility Conversion in Thermo-sensitive Genic Male Sterile(TGMS) Lines of Brassica juncea

[Objective] This study was performed to screen functional genes related to the fertility conversion of thermo-sensitive genic male sterile （TGMS） lines of Brassica juncea L. [Method] A B. juncea TGMS line K121S was selected as the experimental material. The total RNAs were isolated from fertile and sterile pollens at different development stages, including mother cell stage, tetrad stage, tricellular pollen stage and maturity stage. DDRT-PCR was carried out to identify differentially expressed genes. [Result] A total of 44 differentially expressed cDNA fragments were identified with Dot blot. And seven candidate genes related to fertility conversion of K121S were screened out by BLASTN, including callose synthase gene, aldehyde dehydrogenase gene and RNA polymerase I transcription factor RRN3 gene which were differentially expressed at the transcriptional level, H＇-ATPase gene, fructose diphosphate aldolase -class I gene, teucine-rich repeat receptor-Jike serine/threonine- protein kinase gene and alkaline/neutral invertase gene, which were differentially expressed at the post-transcriptional level. [Conclusion] The results of this study will help to explain the molecular mechanism of thermo-sensitive genic male sterility of B. juncea.

Studies on Breeding and Application of Thermo-sensitive Genie Male Sterile Line 402S in Brassica napus Ⅱ.Evaluation of Heterosis and Combining Ability

Augmented randomized complete block test was conducted to evaluate the heterosis of 80 hybrid combinations from TGMS line 402S and its original parent Xiangyou 91S,and the combining a-bility of 40 testcrossing lines.The results of identification test showed that among 47 combinations yielding over the control Xiangyou 15,17 ones with 402S and 3 ones with Xiangyou 91S overyielded more than 20%,reaching the significant level of 1 %;and among 51 combinations yielding over their corresponding higher yield parents,18 ones with 402S and 9 ones with Xiangyou 91S overyielded at 5% or 1% significant level.The test for the GCA effect of all parents indicated that 402S possessed a stronger combining ability than Xiangyou 91S on yield,ailiquae of main inflorescence,total siliquae per plant,seed yield of single plant and 1000 seed weight.10 testcrossing lines with high GCA were picked out for next testcrosses.Among 8 agronomic traits,total siliquae per plant and seed yield of single plant were regarded as the key selecting indexes according to the correlation analysis between yield and the agronomic traits on heterosis and on the GCA effect of all parents.