MicroRNA在动物细胞和病毒间的调控作用

微小RNA(microRNA,miRNA)在介导病毒-动物细胞相互作用过程中发挥着重要的作用。miRNA通过诱导mRNA降解和抑制翻译等机制调节宿主细胞和病毒自身的靶基因,参与宿主细胞对病毒侵染的抵御和病毒对宿主的抵抗与逃避过程。本文从宿主来源miRNA对病毒的作用、病毒来源miRNA对宿主和病毒本身的作用,以及两种来源miRNA的相互作用关系等几个方面进行简要综述,同时对miRNA的应用前景也进行了初步探讨,以期对深入理解病毒-宿主间miRNA的相互作用机制和病毒病的防治提供新的思路与方法。     

Significance of host complexity and diversity for race-specific leaf-rust resistance in self-fertile synthetic rye populations

Leaf rust (Puccinia recondita Rob. ex. Des.) is the most frequently occurring leaf disease in German winter rye (Secale cereale L.). To test the usefulness of race‐specific resistance genes, the effects of increased host diversity and complexity by producing two‐ and four‐line synthetics from inbred lines carrying different resistance genes were analysed. Thirty‐three synthetics along with two full‐sib families and one hybrid variety were tested in 17 environments in Germany under natural infections. For comparison, the parent lines of the synthetics were evaluated in 11 environments. Only two synthetics and the full‐sib families were resistant across all environments. Observed resistance levels of the synthetics were highly correlated (r = 0.83, P = 0.01) with those predicted from the parental values. Host complexity had a minor effect in two‐line synthetics only. In conclusion, the effectiveness of race‐specific leaf‐rust resistances among environments, and increasing the host complexity and diversity does not lead to a higher resistance level than that expected from the resistances of the parents.     

Wild relatives of sorghum as sources of resistance to sorghum shoot fly, Atherigona soccata

The levels of resistance to shoot fly, Atherigona soccata in sorghum germplasm are low to moderate and therefore, we evaluated 17 wild relatives of sorghum under field and greenhouse conditions as an alternate source of genes for resistance to this pest. Thirty-two accessions belonging to Parasorghum , Stiposorghum and Heterosorghum did not suffer any shoot fly damage under multi-choice conditions in the field, while one accession each of Heterosorghum ( Sorghum laxiflorum ) and Chaetosorghum ( S. macrospermum ) suffered very low shoot fly damage. Accessions belonging to S. exstans (TRC 243601), S. stipoideum (TRC 243399) and S. matarankense (TRC 243576) showed absolute non-preference for oviposition under no-choice conditions. Accessions belonging to Heterosorghum , Parasorghum and Stiposorghum were preferred for oviposition, but suffered low deadheart formation. Manual infestation of seedlings with shoot fly eggs did not result in deadheart formation in some of the accessions belonging to S. exstans (TRC 243601), S. stipoideum (TRC 243399), S. matarankense (TRC 243576) and S. purpureosericeum (IS 18944). Larval mortality was recorded in main stems of the Parasorghums . Within section Sorghum , accessions belonging to S. bicolor ssp. verticilliflorum were highly susceptible to shoot fly, as were those of S. halepense . However, a few accessions such as IS 18226 (race arundinaceum ) and IS 14212 ( S. halepense ) resulted in reduced survival and fecundity. Wild relatives of sorghum exhibited very high levels of antibiosis to A. soccata , while only low levels of antibiosis have been observed in the cultivated germplasm. Therefore, wild relatives with different mechanisms of resistance can be used as a source of alternate genes to increase the levels and diversify the basis of resistance to shoot fly, A. soccata .     

烤烟烟叶腺毛分泌物提取方法初探

为探索烤烟烟叶腺毛分泌物提取效果最佳的方法,以烤烟品种K326、云烟85和红花大金元为材料,采用二氯甲烷作为溶剂,比较不同提取级数和不同提取时间前后叶片重量的变化。结果表明,在烟叶腺毛分泌物提取方法的不同提取级数的效果比较中,3个烤烟品种均以前3级提取的变化最明显,而之后增加提取级数,叶片重量变化不明显;不同提取时间对叶片的重量变化影响不大。这说明采用3级提取作为烤烟叶片腺毛分泌物的提取方法比较适宜     

水生植物分泌物对微生物影响的研究

植物分泌物和功能微生物的相互作用对于植物－微生物系统净化水质效果扮演着重要的作用.加入3种植物(黄花水龙、凤眼莲、伊乐藻)的分泌物对接种的氮循环微生物和光合细菌进行培养,结果表明:3种水生植物粗分泌物对光合细菌都起到了促进生长的作用,但是对于氮循环微生物却有不同的作用效果:分泌物对氨化菌和反硝化菌生长有促进作用,但是对于亚硝化菌和反硝化菌表现出抑制的作用,而且不同水生植物的分泌物对微生物作用大小也有所差异.这些结果能为今后进行植物－微生物修复体系中选择何种水生植物和接种微生物才能起到最佳的修复效果提供依据.     

The effect of environment on level of resistance to Phomopsis leptostromiformis in lupins and implications for resistance breeding to this disease

Summary Four varieties of lupins were sown at three planting dates and the level of Phomopsis leptostromiformis measured on the mature stems. When averaged over planting dates the varieties did not differ in resistance to this disease, however there were highly significant interactions between varieties and planting dates for level of disease. The implications of this result for resistance breeding to Phomopsis leptostromiformis are discussed.     

Effects of glandular trichomes on the development of Phytophthora infestans infection in potato (S. tuberosum)

S. berthaulltii Hawkes, a wild potato species, possesses two types of glandular trichomes on its leaf surface: types A and B wich confer resistance to insects. Preliminary results indicated that the presence of glandular trichomes also confers resistance to Phytophthora infestans, the causal agent of late blight. In this paper we report the evaluation of trichome characteristics (density and exudate activities) performed on 8 lines of potato, including the control varieties Desirée and Tropicana, 5 hybrid lines derived from intercrosses and backcrosses between S. tuberosum and S. berthaultii and one accession of S. berthaultii. Whole plants of the 8 genotypes were inoculated with a spore suspension of Phytophthora infestans in order to evaluate their resistance to late blight. The resultant disease incidence correlated negatively with type A trichome density and with polyphenol-oxidase (PPO) activity of type A trichome glands. The removal of type B trichomes exudate by leaf dipping in ethanol did not influence the disease development after artificial inoculation of detached leaves. Type B trichome exudate was extracted and the fraction corresponding to Fatty Acids Sucrose Esters (FASE) was recovered after Thin Layer Chromatography and tested on the fungal mycelium in vitro. The FASE exhibited a slight inhibitory effect on mycelium growth. The results of the experiments are discussed, and several hypotheses regarding the possible role of types A and B trichomes are formulated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of a core collection of Brassica oleracea accessions for resistance to Brevicoryne brassicae, the cabbage aphid

A rapid, simple and reliable technique was developed for evaluating Brassica accessions in the glasshouse for resistance to Brevicoryne brassicae, the cabbage aphid. Brassica accessions were grouped into crop types with similar habit and vigour for evaluation. 401 Brassica oleracea accessions, representing the genetic and geographic diversity of the species, were evaluated for resistance to a population of B. brassicae collected originally from HRI, Wellesbourne. Ninety eight accessions were identified as being moderately resistant (grade 3) or partially resistant (grade 4). Re-testing of accessions in the glasshouse identified 12 moderately resistant and 43 partially resistant accessions. The most promising gene pool was kale, where a higher than expected number of resistant accessions were found. Three of the kales were consistently rated as moderately resistant in all tests. In contrast the broccoli gene pool was a poor source of resistance with less (one out of 46) resistant accessions than expected. Eleven of the kales graded 3 were tested in the field in 1995 and resistance to B. brassicae was confirmed. Ten accessions were also tested for resistance to two additional populations of B. brassicae, one from Greece and the other from Portugal. The results provided no evidence of aphid biotype/host specific differences in the resistance of these B. oleracea accessions. This revised version was published online in August 2006 with corrections to the Cover Date.     

南岭黄檀的栽培技术与效益分析

文章通过分析南岭黄檀的生长特性,详细介绍其栽培技术,并从经济、生态、社会三个方面作效益分析,从而总结南岭黄檀是一种优质的紫胶虫寄主树,适合在梅州地区种植,能快速带动山区人民致富。