园林有害植物——五爪金龙

五爪金龙(Ipomoea cairica)是旋花科多年生草质藤本植物,原产北美.它生长迅速,攀爬能力强,现已成为我国华南地区仅次于薇甘菊(Mikania micrantha )的草质藤本害草,对广州、深圳及粤东地区的公园绿地、风景林、人工林、果园、茶园、苗圃等造成了极大的危害.文章详细介绍了五爪金龙的形态特征、生物学特性和生态学特征、危害状况以及存在的问题,以期引起人们对该植物足够的警惕,并为有关部门对该植物进行科学有效地防范和治理提供依据.     

Identification of QTLs for Starch Content in Sweetpotato （Ipomoea batatas （L.） Lam.）

Sweetpotato （Ipomoea batatas （L.） Lam.） breeding is challenging due to its genetic complexity. In the present study, interval mapping （IM） and multiple quantitative trait locus （QTL） model （MQM） analysis were used to identify QTLs for starch content with a mapping population consisting of 202 F1 individuals of a cross between Xushu 18, a cultivar susceptible to stem nematodes, with high yield and moderate starch, and Xu 781, which is resistant to stem nematodes, has low yield and high starch content. Six QTLs for starch content were mapped on six linkage groups of the Xu 781 map, explaining 9.1-38.8% of the variation. Especially, one of them, DMFN 4, accounted for 38.8% of starch content variation, which is the QTL that explains the highest phenotypic variation detected to date in sweetpotato. All of the six QTLs had a positive effect on the variation of the starch content, which indicated the inheritance derived from the parent Xu 781. Two QTLs for starch content were detected on two linkage groups of the Xushu 18 map, explaining 14.3 and 16.1% of the variation, respectively. They had a negative effect on the variation, indicating the inheritance derived from Xu 781. Seven of eight QTLs were co-localized with a single marker. This is the first report on the development of QTLs co-localized with a single marker in sweetpotato. These QTLs and their co-localized markers may be used in marker-assisted breeding for the starch content of sweetpotato.     

Cloning and Functional Analysis of Lycopene ε-Cyclase （lbL C Ye） Gene from Sweetpotato, Ipomoea batatas （L.） Lam.

This paper reported firstly successful cloning of lycopene ε-cyclase(IbLCYe) gene from sweetpotato,Ipomoea batatas(L.) Lam.Using rapid amplification of cDNA ends(RACE),IbLCYe gene was cloned from sweetpotato cv.Nongdafu 14 with high carotenoid content.The 1 805 bp cDNA sequence of IbLCYe gene contained a 1 236 bp open reading frame(ORF) encoding a 411 amino acids polypeptide with a molecular weight of 47 kDa and an isoelectric point(pI) of 6.95.IbLCYe protein contained one potential lycopene ε-cyclase domain and one potential FAD(flavinadenine dinucleotide)/NAD(P)(nicotinamide adenine dinucleotide phosphate)-binding domain,indicating that this protein shares the typical characteristics of LCYe proteins.The gDNA of IbLCYe gene was 4 029 bp and deduced to contain 5 introns and 6 exons.Real-time quantitative PCR analysis revealed that the expression level of IbLCYe gene was significantly higher in the storage roots of Nongdafu 14 than those in the leaves and stems.Transgenic tobacco(cv.Wisconsin 38) expressing IbLCYe gene accumulated significantly more β-carotene compared to the untransformed control plants.These results showed that IbLCYe gene has an important function for the accumulation of carotenoids of sweetpotato.