Analysis of QTLs for seed low temperature germinability and anoxia germinability in rice (Oryza sativa L.)

Direct seeding instead of transplanting for rice (Oryza sativa L.) has increasingly been used in northern and eastern China because of labor and cost saving. However, poor germinability is still one of the major problems faced in the adoption of direct seeding under low temperature (low temperature germinability: LTG) and anoxia (anoxia germinability: AG) condition. To gain an understanding of the genetic control of seed germinability under these unfavourable conditions, two rice lines, USSR5 (japonica type) and N22 (indica type) and F₂ individuals derived from the cross USSR5 × N22 were tested for LTG and AG. USSR5 and N22 differ significantly for both LTG and AG. The LTG of the F₂ individuals ranged from 0 to 100% after a 10 days incubation. AG ranged from 0.0 to 4.0 cm shoot length. Based on segregation in the F₂ population, a linkage map was constructed using 121 SSR markers. The map covered 1821.5 cM, with a mean inter-marker distance of 16.7 cM. Eleven putative QTLs for LTG were detected, one on each of chromosomes 3–5, 7, 9–11, and four on chromosome 5. The USSR5 alleles in all these QTLs acted to increase LTG. Two QTLs for AG were located on chromosomes 5 and 11, respectively, at both of which the USSR5 alleles acted to increase AG. We propose that USSR5 could make a major contribution to improving LTG and AG in rice breeding programs.     

Involvement of actin filament association in hypersensitive reactions in potato cells

In potato tissues after either penetration by an incompatible race ofPhytophthora infestans, the potato late blight fungus, or treatment with hyphal wall components (HWC) prepared fromP. infestans, cytoplasmic aggregation is observed as one of the earliest resistance reactions. In potato protoplasts, the number of aggregated protoplasts increased after treatment with HWC. The increase was repressed by treatment with cytochalasin D, staurosporine, verapamil, ophiobolin and quinacrine prior to HWC treatment, suggesting that cytoplasmic aggregation in potato protoplasts was connected with actin filament association, protein phosphorylation, Ca²⁺, calmodulin and phospholipase reactions. The ratio of monomer-actin in potato tissues was decreased by treatment with HWC, while the decrease was repressed by treatment with cytochalasin D, staurosporine, ophiobolin and quinacrine prior to HWC treatment. These inhibitors inhibited the accumulation of rishitin, a potato phytoalexin, which occurs in potato tissues treated with HWC. The results imply that the factors involved in signal transduction might be connected with the cytoskeleton, especially actin filament association, during the initiation of defence responses in potato cells.     

不同生态类型大麦品种(系)杂交后代主要农艺性状的分析

为了解不同生态类型大麦品种(系)杂交后代主要农艺性状的分离规律,以美国引进的优质啤酒春大麦品系ABI 18-152为母本、江苏主推冬啤酒大麦品种扬农啤7号为父本配制的杂种F1、F2群体及亲本为材料,测定株高、穗长、穗下节间长、单株穗数、主穗粒数、千粒质量、单株产量、粒长、粒宽、粒长宽比10个农艺性状,对各性状的杂种优势及分离规律进行分析。结果表明:除主穗粒数和粒宽在亲本间差异不具统计学意义,其余8个性状在亲本间均具有统计学意义(P<0.05)或高度统计学意义(P<0.01)。杂种F1的10个性状大多存在正向中亲优势和负向高亲优势,优势大小在性状间存在较大差异。株高类性状和单株产量性状在杂种F2群体内变异程度高,变异系数均在10%以上,单株产量的变异系数最大(58.65%);籽粒粒型性状在杂种F2群体内的变异程度较低,其变异系数在5%左右,粒长的变异系数最小(4.52%)。降低单株株高,对影响单株产量的性状加强选择,可实现矮秆高产品种的选育。     

糖基转移酶基因TaUGT7分子表达特征及抗赤霉病作用分析

为研究小麦UDP-葡萄糖基转移酶7(UDP-glycosyltransferase 7,TaUGT7)的抗赤霉病功能,利用DNAMAN 6.0软件对Ta UGT7及其同源蛋白进行序列比对,应用实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)技术分析经赤霉菌Fusarium graminearum和脱氧雪腐镰刀菌烯醇（deoxynivalenol,DON）处理后的苏麦3号小穗中TaUGT7基因的表达特征,利用基因枪在洋葱表皮细胞瞬时表达TaUGT7-eGFP进行亚细胞定位,采用农杆菌介导法在小麦品种Fielder中过量表达TaUGT7基因并进行赤霉病抗性鉴定。结果表明,TaUGT7在氨基酸序列上与已知赤霉病抗性相关UGT相似性较低;TaUGT7在赤霉菌接种24 h后开始被诱导表达,在DON处理2 h后逐步被诱导表达;Ta UGT7蛋白亚细胞定位于细胞膜和细胞核中;qRT-PCR检测发现,TaUGT7在8株独立的过表达转基因株系中均有不同程度的上调表达;与野生型对照相比,过表达株系TaUGT7-395和TaUGT7-457中的平均病小穗率显著下降。...