Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to lar...Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.展开更多
The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molec...The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molecular linkage map of 97 SSR markers was constructed using interval mapping and covered a total length of 1 357.3 cM with an average distance of 13.99 cM, between adjacent markers in rice genome. The CTBP of F3 lines was evaluated at 5℃, and the survival seedling rate after treating under low temperature at the budburst period was used as cold tolerance index for CTBP. A continuous distribution near to normal for CTBP was observed in F3 lines, CTBP is a quantitative trait which was controlled by some genes. Three QTLs on chromosomes 2, 4 and 7 which are associated with CTBP were detected on location of RM6-RM240, RM273-RM303, RM214-RM11, respectively, which explained the range of the observed phenotypic variance from 11.5 to 20.5%. qCTBP4 detected on RM273-RM303 of chromosome 4 explained 20.5% of the observed phenotypic variance. The effect of qCTBP4’s allelic gene comes from Jileng 1., MSc; Correspondence展开更多
Three rice varieties and several F3 lines with high and low cold tolerance, selected from F3 segregation lines of two crossesMilyang 23/Tong 88-7 and Milyang 23/TR22183 were used to analyze the effects of cold tolera...Three rice varieties and several F3 lines with high and low cold tolerance, selected from F3 segregation lines of two crossesMilyang 23/Tong 88-7 and Milyang 23/TR22183 were used to analyze the effects of cold tolerance on the response of grainquality to cold water irrigation. The result showed that cold water irrigation led to the decrease of rice grain size. Thelength, length-width ratio and weight of brown rice grain were more sensitively affected by cold water irrigation than thewidth and thickness. The shape of brown rice grain was not significantly affected by the selection for cold tolerance at theseedling stage (CTS). The gel consistency, amylose content, peak viscosity, cool viscosity, breakdown viscosity andconsistency viscosity were decreased, while alkali digestibility value and protein content were increased by cold waterirrigation. Under normal irrigation condition the physicochemical properties of milled rice and viscogram components ofmilled rice flour were not significantly different between lines with high and low cold tolerance. Under cold water irrigationthe amylose content, peak viscosity, hot viscosity, final viscosity of rice lines with high CTS or high cold tolerance at thebooting stage (CTB) were higher, while the protein content, setback viscosity, breakdown ratio and setback ratio werelower, than those of rice lines with low cold tolerance. This implied that the cold water response of rice grain quality wasless sensitive in the lines with high cold tolerance than in the lines with low cold tolerance, and the varietal improvementfor cold tolerance would be important for grain quality improvement at the same time.展开更多
文摘Cells and cell-free solutions of the culture filtrate of the bacterial symbiont, Xenorhabdus nematophila taken from the entomopathogenic nematode Steinernema carpocapsae in aqueous broth suspensions were lethal to larvae of the diamondback moth Plutella xylostella. Their application on leaves of Chinese cabbage indicated that the cells can penetrate into the insects in the absence of the nematode vector. Cell-free solutions containing metabolites were also proved as effective as bacterial cells suspension. The application of aqueous suspensions of cells of X.nematophila or solutions containing its toxic metabolites to the leaves represents a possible new strategy for controlling insect pests on foliage.
基金supported by the National Natural Science Foundation of China(30070421)the 10th Five-Year National Key Research Program(2001BA511B02)Cooperative Research Between China and Korea(2002-2004).
文摘The quantitative trait loci (QTLs) for cold tolerance at the budburst period (CTBP) was identified using a F2:3 population including 200 lines derived from a cross of indica and japonica Milyang 23/Jileng 1. A molecular linkage map of 97 SSR markers was constructed using interval mapping and covered a total length of 1 357.3 cM with an average distance of 13.99 cM, between adjacent markers in rice genome. The CTBP of F3 lines was evaluated at 5℃, and the survival seedling rate after treating under low temperature at the budburst period was used as cold tolerance index for CTBP. A continuous distribution near to normal for CTBP was observed in F3 lines, CTBP is a quantitative trait which was controlled by some genes. Three QTLs on chromosomes 2, 4 and 7 which are associated with CTBP were detected on location of RM6-RM240, RM273-RM303, RM214-RM11, respectively, which explained the range of the observed phenotypic variance from 11.5 to 20.5%. qCTBP4 detected on RM273-RM303 of chromosome 4 explained 20.5% of the observed phenotypic variance. The effect of qCTBP4’s allelic gene comes from Jileng 1., MSc; Correspondence
文摘Three rice varieties and several F3 lines with high and low cold tolerance, selected from F3 segregation lines of two crossesMilyang 23/Tong 88-7 and Milyang 23/TR22183 were used to analyze the effects of cold tolerance on the response of grainquality to cold water irrigation. The result showed that cold water irrigation led to the decrease of rice grain size. Thelength, length-width ratio and weight of brown rice grain were more sensitively affected by cold water irrigation than thewidth and thickness. The shape of brown rice grain was not significantly affected by the selection for cold tolerance at theseedling stage (CTS). The gel consistency, amylose content, peak viscosity, cool viscosity, breakdown viscosity andconsistency viscosity were decreased, while alkali digestibility value and protein content were increased by cold waterirrigation. Under normal irrigation condition the physicochemical properties of milled rice and viscogram components ofmilled rice flour were not significantly different between lines with high and low cold tolerance. Under cold water irrigationthe amylose content, peak viscosity, hot viscosity, final viscosity of rice lines with high CTS or high cold tolerance at thebooting stage (CTB) were higher, while the protein content, setback viscosity, breakdown ratio and setback ratio werelower, than those of rice lines with low cold tolerance. This implied that the cold water response of rice grain quality wasless sensitive in the lines with high cold tolerance than in the lines with low cold tolerance, and the varietal improvementfor cold tolerance would be important for grain quality improvement at the same time.
