基于SRAP分析的梨授粉品种亲缘关系对砀山酥梨石细胞含量的影响

利用SRAP分子标记,从88对引物中筛选出34对引物组合,分析砀山酥梨母本与授粉品种之间的亲缘关系,探讨梨授粉品种亲缘关系对砀山酥梨石细胞含量的影响。结果表明:授粉品种紫酥、鸭梨和马蹄黄与砀山酥梨亲缘关系较远,授粉品种华山、幸水和圆黄与砀山酥梨亲缘关系较近;砀山酥梨自然授粉果实石细胞含量为0.61%;选用紫酥、鸭梨和马蹄黄作授粉树时,果实石细胞含量分别为0.34%、0.33%、0.36%,低于自然授粉的砀山酥梨;选用华山、幸水和圆黄作授粉树时,果实石细胞含量分别为0.84%、0.70%、0.66%,高于自然授粉的砀山酥梨。选用与砀山酥梨亲缘关系较远的梨品种作授粉树可减少砀山酥梨石细胞含量,改善口感     

不同基因型梨木质素代谢对石细胞含量和果实口感的影响

以五种基因型梨果实为材料,对石细胞团的大小、分布进行解剖学观察,并测定石细胞、木质素含量和木质素相关合成酶PAL、POD、PPO活性,探讨不同基因型梨果实木质素代谢对石细胞含量及口感的影响.结果表明,不同基因型梨木质素含量高时,石细胞含量也高,石细胞团相对较大,分布较密集,口感差.各基因型的梨木质素、石细胞含量和大小为...     

云南红梨PyMT基因的克隆、原核表达和功能分析

金属硫蛋白(metallothioneins,MTs)是一种在生物中普遍存在的多功能蛋白.根据云红梨1号光特异性差减文库中获得的PyMT(Pyrus pyrifolia metallothionein)基因序列,PCR扩增4种红梨PyMT的基因组序列并进行序列分析;通过RT-PCR方法从云红梨1号果皮中扩增出PyMT基因,并将其命名为PyMT1(Pyrus pyrifo-lia metallothionein 1).构建原核表达载体pGEX-4T-1-PyMT1,在E.coli BL21中进行表达;通过在液体培养基中添加不同浓度的重金属离子,检测转化菌和对照菌的的生长曲线,分析PyMT1的功能.序列分析表明,PyMT1是典型的Metallothion 2.PyMT1氨基酸序列系统发育分析表明,PyMT1与MdMT亲缘关系最近.SDS-PAGE结果表明所表达蛋白与预期的大小一致;生长曲线结果表明工程菌对重金属离子Zn、Cu、Cd具有一定的耐受性.这些结果为进一步纯化、鉴定目的蛋白和研究其结构和功能奠定了基础.     

Mapping of two suppressors of OVATE (sov) loci in tomato

Tomato fruit shape varies significantly in the cultivated germplasm. To a large extent, this variation can be explained by four genes including OVATE. While most varieties with the OVATE mutation bear elongated fruits, some accessions carry round fruit, suggesting the existence of suppressors of OVATE in the germplasm. We developed three intraspecific F₂ populations with parents that carried the OVATE mutation but differed in fruit shape. We used a bulk segregant analysis approach and genotyped the extreme classes using a high-throughput genotyping platform, the SolCAP Infinium Assay. The analyses revealed segregation at two quantitative trait loci (QTLs), sov1 and sov2. These loci were confirmed by genotyping and QTL analyses of the entire population. More precise location of those loci using progeny testing confirmed that sov1 on chromosome 10 controlled obovoid and elongated shape, whereas sov2 on chromosome 11 controlled mainly elongated fruit shape. Both loci were located in intervals of <2.4 Mb on their respective chromosomes.     

Genetic diversity and gene flow estimates among three populations of Botryodiplodia theobromae causing die-back and bark canker of pear in Punjab

Three populations of Botryodiplodia theobromae causing die-back and bark canker of pear in Punjab were analysed to know about the genetic diversity, gene flow, heterogeneity and the probable rate of spread of races capable of overcoming the resistance present in elite cultivars. There was no relationship between the morphologically similar isolates and their pathogenic behaviour. Majority of the isolates of B. theobromae within and among the populations produced lesions of 1.9–7.2 × 0.8–3.1 cm size on detached pear twigs cv. Punjab Beauty. Incubation period and per cent infection also varied within and among the three populations of the pathogen. The genetic diversity was calculated on the basis of allele frequencies of nine simple sequence repeat (SSR) markers using Nei's genetic diversity formulae. Allele frequencies (X_ij ) varied significantly among the three populations ranging from 0.0 to 1.0. The mean genetic diversities within population (H _S) also varied in all the locations ranging from 0.18 to 0.36 indicating a high genetic diversity within the population. The total genetic diversity across all the populations (H _T) ranged between 0.1 and 0.5 with a mean of 0.36, and differed significantly from the mean H _S (0.25). Diversity indices of SSR loci varied from low (H _S < 0.1) to high (H _S > 0.4) across all the populations (G _ST) of B. theobromae in Punjab which were consistent over the presumed SSR loci with a mean G _ST of 0.29. The lower G _ST values of 0.13, 0.10, 0.11 and 0.13 were observed at LAS15-16, LAS27-28, BOT17-18 and BOT35-36 loci, respectively, showing high genetic diversity among all the isolates. However, at BOT19-20 locus, the G _ST value observed was 0.72 thereby indicating low diversity in the population at this locus. Out of 25 loci, 8 loci showed the gene flow (Nm) < 1 indicating a high genetic differentiation within the population and the remaining 6 loci showed the Nm > 1 indicating the frequent existence of gene flow across the populations of B. theobromae. Pairwise comparison (G _ST) values among all the loci were ranging from 0.18 to 0.19, which indicate a low genetic differentiation among the populations of B. theobromae. The high genetic diversity (H _S) within the population was observed in the present study suggesting that B. theobromae possess high variability in Punjab. Keeping this in view, new races would be expected soon outside the state of origin, as naturally occurring gene flow is likely to be increased by the human activity for comprehensive cultivation of pear in the near future. Therefore, it is difficult to predict the durability of resistant sources in Punjab, which in turn emphasises the identification and introgression of R genes into commercial cultivars.     

一株高效表面活性剂产生菌的筛选及其活性产物的结构与性质

采用血平板法结合表面张力法从大庆油田高台子低渗透油藏采出水中筛选出一株高效表面活性剂产生菌,编号为DY-9.16S rDNA序列同源性比对结果显示,DY-9与地衣芽孢杆菌(Bacillus licheniformis)的序列相似性达99％.在45℃、180 r·min-1振荡培养条件下,DY-9在20 g·L-1糖蜜为碳源的培养基中生长良好,24h内将发酵液的表面张力从初始的69.3 mN·m-1降低至26.5 mN·m-1.48 h发酵液中表面活性剂粗品的产量达0.48 g·L-1,其临界胶束浓度为28 mg·L-1.菌株产生的表面活性剂在高温(120℃,1h)、高盐(12％ NaCl)及较宽的pH(2～12)条件下保持稳定,溶液的表面张力低于30 mN·m-1.经傅里叶变换红外光谱(IF-TR)和高效液相色谱-质谱联用(HPLC-MS)分析,菌株DY-9的表面活性产物为环状脂肽类表面活性剂.     

梨枣花果期耗水规律及其与茎直径变化的相关分析

设置4个水分处理,研究了4年生梨枣2010年及2011年花果期不同供水条件下土壤水分动态和耗水规律,分析了梨枣日耗水量与茎直径变化间的相关性,建立回归模型.结果表明:(1)2a内各处理梨枣耗水量随土壤供水量的增加而增大,其日耗水量最大值均出现在灌水后1周内;各处理果实膨大期日耗水强度大于开花坐果期.(2)2a内各处理茎直径日变化平均值(MTD)、茎直径日最大值(MXTD)均符合Logistic函数关系,MXTD与MTD在表征梨枣茎秆生长规律方面效果一致,各处理茎直径变化指标(MTD、MXTD)增长率因水分处理的不同而存在差异.(3)高水分(T1处理)条件下茎直径变化指标(MTD、MXTD、MDS(茎直径日最大收缩量)、DG(茎直径日生长量))在表征枣树耗水状况方面不敏感;在低水分(T4处理)条件下,日耗水量与茎直径日最大收缩量(MDS)相关系数较其他3个茎直径变化指标(MTD、MXTD、DG)高且达极显著水平,说明MDS能够更好的表征低水分处理的梨枣耗水规律.在此基础上建立耗水量与茎直径变化回归模型,为评价梨枣耗水状况提供依据.     

砧木对梨叶芽休眠的影响及其与多胺代谢的关系

以分别嫁接在杜梨和豆梨上的砂梨品种‘丰水’为试材,研究了2008和2009年11～12月气温变化和不同砧木对‘丰水’梨叶芽休眠进程的影响,分析叶芽中游离态和束缚态内源多胺种类和含量的变化,结果表明：嫁接在豆梨上的‘丰水’叶芽自然休眠结束的时间要比嫁接在杜梨上的‘丰水’叶芽早10d左右,且游离态和束缚态腐胺（Put）、戊二胺（Cad）、己二胺（Hex）、亚精胺（Spd）和精胺（Spm）5种内源多胺含量开始升高的时间与供试材料叶芽自然休眠结束的时间一致,表明梨叶芽的休眠进程与砧木种类和多胺代谢有密切关系,尤其是与束缚态多胺含量变化的关系更为密切。     

套袋对梨果实发育过程中糖组分及其相关酶活性的影响

以翠冠和黄金梨为试材,测定套袋和未套袋(对照)梨果实发育时期果实中蔗糖、葡萄糖、果糖和山梨醇含量以及蔗糖代谢相关酶酸性转化酶(AI)、中性转化酶(NI)、蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)的活性,并对果实中糖组分积累与酶活性的关系进行了分析.结果表明:(1)两梨品种套袋果实在发育过程中蔗糖、葡萄糖、果糖、山梨醇和糖代谢相关酶活性变化趋势与对照基本一致,套袋果实糖含量均低于对照但差异不显著,而各相关酶活性在两类果实间差异表现各异.(2)在梨果实发育早期,果实中以分解酶类为主,糖分积累低;发育后期以合成酶类为主,糖分积累多.(3)两品种套袋和对照果实AI活性与葡萄糖含量均呈显著或极显著正相关,SS合成方向活性与蔗糖含量均为极显著正相关,且翠冠对照果SPS活性与蔗糖含量呈极显著正相关.可见,套袋通过提高果实发育早期转化酶(Inv)活性,降低果实后期蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)的活性来影响糖分积累,从而影响梨果品质.     

套袋黄冠梨果实花斑病发生与其组织结构变化的关系

以黄冠梨果实为试验材料,在调查套袋处理果实花斑病发生的基础上,研究了套袋及未套袋黄冠梨果实发育过程中的组织结构变化,并分析了发病果实的病部与正常果实组织结构差异。结果显示:(1)套3层袋果实花斑病的发病率为22.5%,而不套袋果实的发生率仅为1.5%。(2)未套袋果实角质层厚,而且呈波纹状分布,并渗入到表皮细胞间隙中,果实发育过程中厚度变化幅度不明显;套袋果实表面的角质层均匀一致,随果实迅速膨大,角质层变薄,且显著薄于未套袋果实,尤其是套3层袋与未套袋果实差异更大;套袋果实表皮细胞呈长方形,且较未套袋果实排列致密;不同套袋处理果实单宁细胞层数随果实发育逐渐减少,在花后90 d后,套袋处理与未套袋处理的厚度无显著差异。(3)套袋果实果肉薄壁细胞排列紧密,胞间隙小,其石细胞大小和密度均较未套袋果实小。(4)套袋果实花斑病发病部位角质层模糊,发病果实正常部位的角质层、表皮层厚度和单宁层均低于正常果实。研究表明,套袋黄冠梨果实表面组织结构发生较明显变化,它对梨果实花斑病的发生有重要影响。