钙-钙调素与小麦苗中热激蛋白的诱导

在 34℃热激条件下 ,种子经钙预处理的小麦苗中的钙调素含量随着热激时间的延长而增加 ,热激 90min时达最大值 ,而种子用钙离子螯合剂EGTA预处理的小麦苗中钙调素含量无明显增加。种子用EGTA及钙调素拮抗剂CPZ和TFP预处理的小麦幼苗在 34℃热激时 ,热激蛋白的合成量减少。 4d的小麦幼苗在34℃或 37℃热激条件下 ,能诱导耐热性的获得 ,分别用EGTA、钙离子通道阻断剂易博定、钙调素拮抗剂TFP或CPZ预处理种子后 ,所得幼苗热诱导的耐热性的提高程度有所下降     

缺磷胁迫对小麦根细胞周期蛋白基因cyc1At表达的影响

用液培方法研究了缺磷胁迫对小麦(TriticumaestivumL.)根系生长的影响。结果表明,随着介质磷水平的提高,小麦根轴长度和植株生长素浓度均降低。在低磷条件下用生长素极性运输抑制剂三碘苯甲酸(TIBA)处理后,小麦的根轴长度明显降低,表明生长素参与了缺磷小麦根轴生长的调控。缺磷小麦根部生长素浓度的提高诱导了细胞周期蛋白基因cyclAt的表达,促进了根分生组织细胞的分裂并驱动了根的生长。     

小麦族几种近缘植物细胞在长期离体培养中的染色体变异

对小麦及其4种近缘属间禾草进行了长时间 (0.5～5.7年, 个别8.6年) 的愈伤组织培养,在继代过程中染色体数目的变异在染色体倍性低的簇毛麦(Haynaldia villosa, 2n=2x=14)及新麦草(Psathyrostachys juncea, 2n=2x=14) 倾向于数目的增大;染色体倍性高的小麦 (Triticum aestivum, 2n=6x=42) 趋向于数目的减少;而倍性居中的羊草 (Leymus chinensis, 2n=4x=28) 既有增大也有减小;染色体倍性最高的高冰草 (Agropyron elongatum, 2n=6x=70) 最为稳定,但也有减少的趋向。愈伤组织的胚性主要与二倍体及亚二倍体的总水平相关。     

Changes in Levels of Endogenous Plant Hormones During Floret Development in Wheat Genotypes of Different Spike Sizes

The levels of endogenous plant hormones regulate floret development and degeneration, and thus grain set in flower crops. This study was undertaken to characterize the changes of endogenous hormone levels during floret development in three wheat (Triticum aestivum L.) genotypes: “97J1" with the highest grain set and fertile florets per spike, “H8679" with the lowest grain set and fertile florets per spike, and a medium, “YM158". The results showed that the peak level of ABA appeared between stamen and pistil differentiation and antherlobe formation of floret development, and the timing delayed with the size of spike (earliest in “H8679” and latest in “97J1”). From antherlobe formation to meiosis, the levels of ABA and GA1+3decreased sharply in the ears of “97J1”, while in the ears of “H8679” there was only a slight decrease in ABA, and even an increase in GA1+3. The ratio of isopentenyladenosine (iPA)/ABA and IAA/ABA in the ears of “97J1” increased sharply from antherlobe formation to meiosis, but changed only slightly in the ears of “H8679”. At antherlobe formation, IAA and GA1+3 levels were higher in the ears of “97J1”, but lower in the ears of “H8679”than in the leaves. At meiosis, ABA, GA1+3 and IAA levels in the “97J1” ears were much lower than in the leaves, but similar in “H8679”. These results indicated that the sharp decreases of ABA and GA1+3 in ears from antherlobe formation to meiosis and the lowest maintenance at meiosis may be favorable for development of fertile florets and enhancement of grain set in wheat.     

Molecular Markers of Ph1 Gene in Chinese Spring and Development of Winter Wheat New Line Harboring ph1b Gene

he genomic DNA of common wheat (Triticum aestivum L.) “Chinese Spring” (CS) and its ph1b mutant were analyzed by using 19 sequence tagged site PCR (STS-PCR) primers, which derived from RFLP probes from barley (Hordeum vulgare L.) chromosome 5H. One marker was identified on wheat chromosome 5BL, which is 5.7 cM (centiMorgan) proximal to Ph1 gene, using the CS homoeologous group 5 nullisomic-tetrasomic, ditelosomic 5BL line and an F2 population from CS×ph1b mutant. This linked PCR marker was converted into a more specific sequence characterized amplified region (SCAR) marker. To obtain a new winter wheat line containing ph1b gene, the authors used a nullisomic 5B line of “Abbodanza”as a bridge parent and crossed respectively with the CS ph1b mutant (donor) and a winter wheat variety, “Jing 411” (recipient). The meiotic chromosome pairing was checked in the progeny of each cross, as well as using the marker-assistant selection of the SCAR marker identified for ph1b gene. After three inter-crossing and one selfing, a relatively stable ph1b substitution line of winter wheat with “Jing 411” background was obtained.     

Inheritance and Sequence Homology Analysis of the Maize DNA Introgressed into the Wheat Doubled Haploid Plant Through Wheat×Maize Cross

A maize (Zea mays L.) genome-specific repeated DNA sequence (clone MR64) has been transferred into one DH line of wheat through wheat (Triticum persicum Vav. ex Zhuk.) and maize cross. In the present study by RFLP analysis the authors proved that this DNA sequence could stably transmit into DH3 plants, the next generation derived from DH2 self-crossing. A similarity search in all DNA databases using BLASTN program showed that the DNA sequence of MR64 had as high as 93% identity to PREM-2 and 79% to Opie-2 in nucleotides. Both PREM-2 and Opie-2 are known as retrotransposons in maize genome, suggesting that MR64 likely is the partial sequence of a maize retrotransposon. Therefore, the results indicate that some retrotransposon might involve the DNA introgression from maize to wheat genome through wide fertilization. Stable inheritance of this maize genome-specific retrotransposon-like DNA in the wheat genome opens up the possibility of using retrotransposon as a new tool for gene tagging, function analysis, and insertional mutagenesis in wheat genome.     

Genetic Diversity of Gli-1, Gli-2 and Glu-1 Alleles in Sichuan Wheat Landraces

Genetic diversity at Gli-1, Gli-2 and Glu-1 loci was investigated in 89 Sichuan wheat ( Triticum aestivum L.) landraces by using acid polyacrylamide gel electrophoresis (APAGE) and SDS-PAGE. In these landraces, a total of 32 gliadin and 3 high-molecular-weight (HMW) glutenin patterns were observed. In total, 14, 15 and 5 alleles were identified at Gli-1, Gli-2 and Glu-1, respectively. At each locus, the alleles in higher frequency were Gli-A1a (89%), Gli-B1 h (46%), Gli-D1a (65%), Gli-A2a (64%), Gli-B2j (45%), Gli-D2 a (48%), Glu-A1c (99%), Glu-B1b (99%) and Glu-D1a (100%). The Nei's genetic variation index (H) of Sichuan wheat landraces was 0.3706, varying from 0 to 0.7087. The highest genetic diversity was found at Gli-B2 locus, while the lowest was found at Glu-D1 . The genetic diversity at Gli loci was higher than that of Glu-1 loci among these landraces, but it was much lower than that of modern wheat cultivars. These results indicated a narrow genetic base of Sichuan wheat landraces. In this study, “Chengdu-guangtou” had the identical gliadin and HMW-glutenin patterns with “Chinese Spring”, further supporting the proposal that “Chinese Spring” is a strain of “Chengdu-guangtou”.     

用顺序GISH-FISH 技术鉴定小麦-中间偃麦草小片段易位系

利用顺序基因组-重复序列原位杂交技术对1个来自中3不育系和普通小麦恢75杂种后代稳定株系H96276-2的染色体组成进行了分析。以中间偃麦草（Agropyronintermedium）基因组DNA为探针的荧光原位杂交结果表明,H96276-2的体细胞中有42条染色体,包括20对小麦染色体和1对小麦-中间偃麦草易位染色体,中间偃麦草染色体的易位片段位于1对小麦染色体的端部。进而用重复序列探针pSc119进行第2次荧光原位杂交,证明H96276-2中的中间偃麦草染色体易位片段位于小麦2B染色体的短臂上。     

与小麦白粉病抗性基因Pm2紧密连锁RAPD标记的筛选研究

以２５６个随机引物对含小麦抗白粉病基因Ｐｍ２近等基因系进行ＲＡＰＤ分析,发现１７个随机引物的扩增产物在抗、感ＮＩＬｓ材料间表现多态性,且其中５个引物经４次以上重复,均获相同结果,其多态性标记分别为ＯＰＭ０８(１６００)、ＯＰＩ０４(１７００)、ＯＰＨ１９(１１００、ＯＰＥ０９(９００)及ＯＰＭ１６(８５０)。当以这５个随机引物对１４个已知含Ｐｍ２基因的抗病材料及９个不含Ｐｍ２基因的感病材料进行检测时,只有标记ＯＰＩ０４(１７００)在１２个抗病材料中出现（另两个抗病材料中未检测到）,而在９个感病材料中均未出现。进一步用 ＯＰI(０４)对１０２株（Ｃｈａｎｃｅｌｌｏｒｘ Ｕｋａ／８＊Ｃｃ）Ｆ２分离群体进行分析,估算出标记ＯＰＩ０４(１７００)与Ｐｍ２基因间的遗传距离为１２．２±３．３ｃＭ。     

Influence of Low Temperature on Spatial-temporal Changes of Ca2+ in Winter or Spring Wheat

Stained with Fluo-3/AM and investigated under the laser scanning confocal microscope (LSCM), the spatial-temporal changes of ［Ca2+］cyt(the free Ca2+ concentration in the cytoplasm) in the protoplasts of mesophyll cells of wheat (Triticum aestivum L.) cultivars with different cold-hardiness under resting and temperature decreasing conditions were compared. The results showed that under the resting condition, the fluorescence intensities in the protoplasts of both cold-sensitive and cold-resistant wheat manifested no significant changes, implying that ［Ca2+］cyt could keep at a stable level under the resting condition although different wheat cultivars were different. However, different dynamics appeared with temperature decreasing from 15℃ to 2℃. In particular, for the cold-resistant wheat, ［Ca2+］cyt level at first increased, followed by drop to the resting level at 2℃, and then increased further when the temperature was below 2℃. On the contrary, the ［Ca2+］cyt level of the cold-sensitive spring wheat increased continuously to the maximal level within the whole range of temperature changes. Based on the above observations, it could be reasonably inferred that different dynamics of ［Ca2+］cyt determines decisively different cold acclimation abilities of plants. Furthermore, the results provide a new supporting evidence for the hypothesis that Ca2+ plays a key role as a primary physiological transducer upon chilling”.