A full-length cDNA that encodes the rice chloroplastic glutamine synthetase 2 gene was isolated from a Minghui 63-normalized cDNA library; and GS2 rice transformants were obtained by an Agrobacterium tumefaciens-media...A full-length cDNA that encodes the rice chloroplastic glutamine synthetase 2 gene was isolated from a Minghui 63-normalized cDNA library; and GS2 rice transformants were obtained by an Agrobacterium tumefaciens-mediated transformation method. Transcripts of the GS2 gene were shown to accumulate at higher levels in the primary transgenic plants in the T0 generation; whereas plants in the T1 generation exhibited a co-suppressed chlorosis phenotype (yellow leaves) accompanied by decreased plant height, few tillers and decreased dry weight. The plants with yellow leaves also displayed a significant decline in GS2 messenger RNA (mRNA) transcriptional level and chlorophyll content; a decrease in total GS activities of ~50% was also found. Although there was no decrease in the concentration of total free amino acids, a change in the concentration of individual amino acids was observed. Our result also indicates a decreased metabolic level (soluble protein content and ammonium concentration) in GS2 co-suppressed plants. A correlation between chlorophyll content and GS2 mRNA expression level was also observed. The GS2 co-suppressed plants showed better performance when complemented with exogenous glutamine, indicating that the lack of an organic nitrogen pool inside the cell is the possible reason for the chlorosis phenotype of the transformants.展开更多
The epidemiology of Tomato chlorosis virus(ToCV)in China is closely associated with its vector whitefly,Bemisia tabaci(Gennadius)MED.However,the transmission characteristics of ToCV by B.tabaci MED remain poorly under...The epidemiology of Tomato chlorosis virus(ToCV)in China is closely associated with its vector whitefly,Bemisia tabaci(Gennadius)MED.However,the transmission characteristics of ToCV by B.tabaci MED remain poorly understood.In this study,we analyzed:1)the horizontal and vertical transmission of ToCV by B.tabaci MED whiteflies;2)the acquisition of ToCV by male and female B.tabaci MED whiteflies after different feeding durations;3)the transmission efficacy of viruliferous male and female B.tabaci MED whiteflies after different inoculation access periods(IAPs);4)the retention of ToCV by viruliferous male and female B.tabaci MED whiteflies after a 48 h acquisition access period(AAP);and 5)the effects of ToCV on host choice of healthy or ToCV-infected tomato plant of viruliferous and non-viruliferous B.tabaci MED at different time points.Our results showed that:1)viruliferous males could not transfer ToCV to non-viruliferous females,and vice versa,viruliferous females could not pass on ToCV to non-viruliferous males.ToCV could not be detected in the F1 generation adults;2)ToCV could be detected within 4.0%of females or males after a 20 min AAP;3)ToCV could be detected in 33.3%of tomato plants inoculated by 10 viruliferous males or females with IAPs of 20 or 30 min;4)the maximum retention time in females was 7 and 5 days in males;and 5)non-viruliferous B.tabaci MED did not show a preference for ToCV-infected tomato plants or healthy tomato plants.However,viruliferous B.tabaci MED whiteflies did prefer to settle on healthy tomato plants over ToCV-infected tomato plants.These findings will be helpful to better understand the epidemiology of the recently emerged plant virus,ToCV,in tomato fields in China.展开更多
基金supported in part by grants from the National Basic Research Program of China (Grant No. 2005CB120905)the National Special Key Project of China on Functional Genomics of Major Plants and Animalsthe National Natural Science Foundation of China and the Cultivation Fund of the Key Scientific and Technical Innovation Project, Ministry of Education of China (Grant No. 707045)
文摘A full-length cDNA that encodes the rice chloroplastic glutamine synthetase 2 gene was isolated from a Minghui 63-normalized cDNA library; and GS2 rice transformants were obtained by an Agrobacterium tumefaciens-mediated transformation method. Transcripts of the GS2 gene were shown to accumulate at higher levels in the primary transgenic plants in the T0 generation; whereas plants in the T1 generation exhibited a co-suppressed chlorosis phenotype (yellow leaves) accompanied by decreased plant height, few tillers and decreased dry weight. The plants with yellow leaves also displayed a significant decline in GS2 messenger RNA (mRNA) transcriptional level and chlorophyll content; a decrease in total GS activities of ~50% was also found. Although there was no decrease in the concentration of total free amino acids, a change in the concentration of individual amino acids was observed. Our result also indicates a decreased metabolic level (soluble protein content and ammonium concentration) in GS2 co-suppressed plants. A correlation between chlorophyll content and GS2 mRNA expression level was also observed. The GS2 co-suppressed plants showed better performance when complemented with exogenous glutamine, indicating that the lack of an organic nitrogen pool inside the cell is the possible reason for the chlorosis phenotype of the transformants.
基金supported by the National Key Research and Development Program of China (2016YFC1201200)the Taishan Mountain Scholar Constructive Engineering Foundation of Shandong, China (tsqn20161040)the National Natural Science Foundation of China (31572064)
文摘The epidemiology of Tomato chlorosis virus(ToCV)in China is closely associated with its vector whitefly,Bemisia tabaci(Gennadius)MED.However,the transmission characteristics of ToCV by B.tabaci MED remain poorly understood.In this study,we analyzed:1)the horizontal and vertical transmission of ToCV by B.tabaci MED whiteflies;2)the acquisition of ToCV by male and female B.tabaci MED whiteflies after different feeding durations;3)the transmission efficacy of viruliferous male and female B.tabaci MED whiteflies after different inoculation access periods(IAPs);4)the retention of ToCV by viruliferous male and female B.tabaci MED whiteflies after a 48 h acquisition access period(AAP);and 5)the effects of ToCV on host choice of healthy or ToCV-infected tomato plant of viruliferous and non-viruliferous B.tabaci MED at different time points.Our results showed that:1)viruliferous males could not transfer ToCV to non-viruliferous females,and vice versa,viruliferous females could not pass on ToCV to non-viruliferous males.ToCV could not be detected in the F1 generation adults;2)ToCV could be detected within 4.0%of females or males after a 20 min AAP;3)ToCV could be detected in 33.3%of tomato plants inoculated by 10 viruliferous males or females with IAPs of 20 or 30 min;4)the maximum retention time in females was 7 and 5 days in males;and 5)non-viruliferous B.tabaci MED did not show a preference for ToCV-infected tomato plants or healthy tomato plants.However,viruliferous B.tabaci MED whiteflies did prefer to settle on healthy tomato plants over ToCV-infected tomato plants.These findings will be helpful to better understand the epidemiology of the recently emerged plant virus,ToCV,in tomato fields in China.
