番茄抗叶霉病基因Cf19的抗性特点及遗传连锁分析

番茄抗叶霉病基因Cf19的抗性范围基本涵盖了中国目前分化出的所有叶霉菌生理小种,且抗性显著;台盼蓝染色结果显示该基因介导的抗性应答中出现明显的超敏反应,强度介于Cf4和Cf9基因之间;遗传连锁分析说明该基因的遗传特性符合单基因显性遗传规律;通过进一步SSR和AFLP分子标记连锁分析,共找到6个与Cf19基因连锁的分子标记,并将该基因初步定位于番茄1号染色体短臂区域。     

甜瓜‘PMR6’抗白粉病基因的遗传及其定位研究

以甜瓜(Cucumis melo L.)感白粉病品种‘Hami413’为受体亲本,抗白粉病品种‘PMR6’为供体亲本构建的255株BC2分离群体为材料,研究‘PMR6’抗白粉病的遗传规律及基因定位。群体遗传分析表明,BC2群体中对白粉病菌Podosphaera xanthii生理小种1的抗性由显性单基因控制,基因命名为Pm-PMR6-1;利用混合分组分析法(Bulked segregant analysis,BSA)从分布于甜瓜12个连锁群上的390个SSR分子标记中筛选出5个多态性标记;通过连锁分析,将该抗性基因定位于12号连锁群SSR标记DM0191与CMBR111之间;根据甜瓜基因组信息设计SSR引物,进一步将该基因定位于SSR12407与SSR12202之间,并且该抗性基因与标记Mu7191共分离;比对基因组序列,两标记间物理距离约226 kb,预测35个候选基因。     

Protective effect of chrysin on mice with insulin resistance

AIM: To explore the effects of chrysin on insulin resistance (IRe) in a mouse model. METHODS: Male C57 mice were randomly divided into control group, IRe group, low-dose chrysin group (IRe+chrysin-low) and high-dose chrysin group (IRe+chrysin-high). After 24 weeks, the body weight, liver index and fat mass in all mice were detected. The blood glucose, insulin level and HOMA-IR were measured to determine the changes of the insulin resistance in the animals. The oxidative stress (SOD, GSH-Px and MDA) was also measured. The mRNA expression of insulin signaling pathway molecules (IR, IRS1, IRS2, Glut2 and Glut4) and inflammatory factors (TNF-α, IL-1β, IL-6 and NF-κB) was analyzed by real-time PCR. The protein levels of IRS1 and p65, and their phosphorylation were detected by Western blot. RESULTS: After 24-week intervention, the indicators in IRe group were higher than those in control group, including body fat deposition, serum glucose, serum insulin, HOMA-IR and liver oxidative stress (P<0.01), indicating that the model of insulin resistance was successfully established. Low dose and high dose of chrysin decreased the body weight, serum glucose, serum insulin and HOMA-IR in the IRe mice (P<0.05). The liver oxidative stress was also reduced in both groups (P<0.05). However, no statistical difference of the indexes between IRe+chrysin-low group and IRe+chrysin-high group was observed. Chrysin upregulated the mRNA expression of IR, IRS1, IRS2, Glut2 and Glut4 (P<0.05), and down-regulated the mRNA expression of various inflammatory factors. The inhibitory effect of chrysin on the mRNA expression of NF-κB was observed (P<0.05), especially in high dose group (P<0.05). It was confirmed that the effect of chrysin on liver IRe was related with the increase in the p-IRS1 levels and decrease in the p-p65 levels by Western blot. CONCLUSION: Chrysin inhibits obesity, hyperglycemia and hyperinsulinemia, and relieves insulin resistance and oxidative stress, which might be closely related to the regulation of insulin signaling pathway and the inhibition of inflammatory factor expression.     

Resistance to the cabbage root fly, Delia radicum, within Brassica fruticulosa

Two transgenic Bt rice lines, KMD1 and KMD2, both containing a synthetic cry1Ab gene from Bt, were crossed with conventional rice varieties. The inheritance of resistance to SSB of KMD1 and KMD2was investigated through LSB and field examination of their progenies, e.g. F₁, BC₁ and F₂ populations. In LSBs, 100.0% of newly hatched SSB larvae died on the second day after feeding on leaf tissues of F₁ and GUS positive BC₁ plants, of which the area of leaf tissues consumed by SSB is also similar to that of transgenic parents. These results imply that the resistance of Bt rice to SSB is dominantly controlled and could be easily exploited in hybrid rice production. Field evaluation showed that segregation ratios for SSB resistance to susceptibility in BC₁ populations fit the ratio of 1:1, which was also confirmed by LSBs. However, in F₂ populations, the ratio was significantly smaller than 3:1 for resistant to susceptible plants in all 6 indica × japonica (KMD1 and KMD2) crosses, though it fitted 3:1 in all 4 japonica × japonica crosses. The results implied that the resistance of Bt rice to SSB was controlled by a dominant gene which was present in a homozygous condition in both KMD1 and KMD2, but the inheritance could be affected by other factors. Assays for Cry1Ab protein showed that, in most crosses, the content of Cry1Ab is significantly higher in leaves of GUS positive F₁, BC₁ and F₂ plants than that in transgenic Bt parent plants, which accounts for the high resistance observed in these plants to SSB. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding for resistance to coffee berry disease in Coffea arabica L. II. Inheritance of the resistance

Summary The inheritance of resistance to coffee berry disease (CBD) has been studied by applying a preselection test to F₂ progenies of a half diallel cross between 11 coffee varieties with different degrees of resistance and to sets of parental, F₁, F₂, B₁₁ and B₁₂ generations of crosses between resistant and susceptible varieties. True resistance to CBD appears to be controlled by major genes on three different loci. The highly resistant variety Rume Sudan carries the dominant R- and the recessive K-genes. The non-allelic interaction between these two genes is of a duplicate nature. The R-locus has multiple alleles with R ₁R₁alleles present in Rume Sudan and the somewhat less effective R ₂R₂alleles in a variety like Pretoria, which also has the K-gene. The moderately resistant variety K7 carries only the recessive K-gene. The arabica-like variety Hibrido de Timor (a natural interspecific arabica x robusta hybrid) carries one gene for CBD resistance on the T-locus with intermediate gene action. It probably inherited this gene from its robusta parent. There is circumstantial evidence that the resistance to CBD is of a stable nature, but it is advisable to accumulate in one genotype as many resistance genes as possible by combining in the breeding programme the resistance of Rume Sudan with that of Hibrido de Timor.     

棉花GbSTK基因调控开花和黄萎病抗性的功能研究

Cotton is an important cash crop, and achieving disease resistance as well as early maturity is an important breeding goal. However, the molecular relationship between disease resistance and early maturity of cotton is still a research gap. In previous study, we identified a GbSTK gene response to V. dahliae that could enhance Verticillium wilt resistance in transgenic Arabidopsis. In this study, we found that GbSTK was more highly expressed in resistance and/or tolerant varieties than in susceptible varieties. Knocking down of GbSTK expression in Nongda 601 showed that the silenced plants displayed serious disease symptoms, with disease index from 27.5 (tolerant) to 63.2 (susceptible), suggesting that GbSTK positively regulates cotton Verticillium wilt resistance. More interesting, we found that GbSTK could promote the development of Arabidopsis. At the flowering time point, the average number of rosette leaves in transgenic lines was 7.5, significantly less than the mock plants, and the transgenic plants bloomed five to seven days earlier than the control. The FT and SOC1 gene, regarded as marker genes in Arabidopsis flowering signaling pathway, maintained higher expression level in transgenic lines than in the mock, indicating that GbSTK could accelerate flowering via regulating FT and SOC1 gene expression. We also obtained 30 candidate proteins that could interacted with GbSTK via yeast double hybrid test, which helped to further revealing the molecular regulatory network of GbSTK. Taken together, we first identified a functional gene that could improve disease resistance and early flowering, which would provide a reference for genetic improvement of cotton disease resistant and early maturity.     

利迪链霉菌A02诱导番茄抗灰霉病作用机制研究——对植株防御酶系的影响

利用利迪链霉菌生防菌株A02发酵液和番茄灰霉病菌对番茄植株进行诱导和接种处理,利用分光光度法测定处理前和处理后1~5 d番茄叶片组织的主要防御酶系——苯丙氨酸解氨酶、过氧化物酶、过氧化氢酶和多酚氧化酶的活性变化。试验结果显示,不接种灰霉病菌而单独诱导处理、接种灰霉病菌后诱导处理和诱导处理后接种灰霉病菌这3种处理都能提高番茄植株各防御酶系的活性,后者酶活性峰值最高,对番茄植株灰霉病的抑制作用也最明显,控制效果达94.92%。     

QTLs for Fusarium head blight response in a wheat DH population of Wangshuibai/Alondra‘s’

Summary A doubled haploid (DH) wheat population derived from the cross Wangshuibai/Alondra‘s’ was developed through chromosome doubling of haploids generated by anther culture of hybrids. Fusarium head blight (FHB) was evaluated for three years from 2001 to 2003 in Jianyang, Fujian Province, China, where epidemics of FHB have been consistently severe. After 307 pairs of simple sequence repeat (SSR) primers were screened, 110 pairs were polymorphic between Wangshuibai and Alondra`s’, and used to construct a genetic linkage map for detection of quantitative trait loci (QTLs). A stable QTL for low FHB severity was detected on chromosomes 3B over all three years, and QTLs on chromosomes 5B, 2D, and 7A were detected over two years. Additional QTLs on chromosomes 3A, 3D, 4B, 5A, 5D, 6B and 7B showed marginal significance in only one year. Six QTLs were detected when phenotypic data from three years were combined. In addition, significant additive-by-additive epistasis was detected for a QTL on 6A although its additive effect was not significant. Additive effects (A) and additive-by-additive epistasis (AA) explained a major portion of the phenotypic variation (76.5%) for FHB response. Xgwm533-3B and Xgwm335-5B were the closest markers to QTLs, and have potential to be used as selectable markers for marker-assisted selection (MAS) in wheat breeding programs.     

丙基双氢茉莉酮酸酯诱导棉花耐黄萎病的效应

温室内以10mg·L 1的丙基双氢茉莉酮酸酯(PDJ)灌根预处理后,再用黄萎病菌(Verticilliumdahliae)孢子悬浮液接种棉苗,处理棉苗与对照相比发病率和病情指数有所降低,表现出对棉花黄萎病的耐病性。对一些生化指标进行测定发现,PDJ灌根和接种都可引起棉苗叶片中苯丙氨酸解氨酶(PAL)活性升高和木质素含量的增加,与此同时棉花叶片中的过氧化物酶(POD)活性及丙二醛(MDA)含量也都有所上升,在此基础上对PDJ诱导棉花耐黄萎病的可能生化机制作了归纳。     

棉铃虫对Bt毒蛋白(Cry1 Ac)抗性品系的选育

1 997～2000年,用含Bt毒蛋白(Cry1Ac)的人工饲料对来自本所试验棉田的棉铃虫经过室内21代中16代次的筛选,筛选后F19代LC50值(4.3646g@L1)比筛选前F2代LC50值(0.2972 g@L-1)提高了14.7倍.试验还发现雌性棉铃虫对Bt毒蛋白的敏感性大于雄性.对Bt毒蛋白抗性品系筛选前后分别测定了其不同菌系(商品制剂Dipel和Xentari)的剂量-死亡率回归线,发现Bt毒蛋白抗性品系与其不同菌系间不存在明显的交互抗性.