DNA fragments of 43 rice varieties were amplified with 11 pairs of primers designed based on resistance gene analogue （RGA） of plants, and the blast resistance of the varieties was identified by inoculation with 33 ...DNA fragments of 43 rice varieties were amplified with 11 pairs of primers designed based on resistance gene analogue （RGA） of plants, and the blast resistance of the varieties was identified by inoculation with 33 isolates of Magnaporthe grisea collected from Yunnan Province, China. Clustering results revealed a significant correlation between the blast resistance and DNA bands with a correlation coefficient of 0.6117 （α=0.01）, indicating that the resistance analysis based on RGA-PCR clustering analysis coincided with that based on inoculation. The correlation coefficients, ranging from 0.1701 to 0.535, however, depended on the primers. Five pairs of primers, S1/AS3, S1 INV/S2 INV, XLRR For/XLRR Rev, Pto-Kinl IN/Pto-Kin2 IN, and NLRR For/NLRR Rev might be applied for blast resistance identification in consideration of their band numbers and polymorphisms, and their correlation coefficients with blast resistance were 0.5305, 0.4898, 0.4059, 0.3719 and 0.3524, respectively. Besides, indica and japonica rice except two highly susceptible varieties, CO39 and Lijiangxintuanheigu could be well classified by the 11 pairs of primers.展开更多
A total of 21 rice varieties were assayed based on RGA-PCR using six pairs of RGA primers and evaluated for leaf blast resistance in the nursery as well. Cluster analysis showed that the varieties could be classified ...A total of 21 rice varieties were assayed based on RGA-PCR using six pairs of RGA primers and evaluated for leaf blast resistance in the nursery as well. Cluster analysis showed that the varieties could be classified into five groups either at the similarity threshold of 0.72 for RGA profiles or at 0.80 for leaf blast severities. Although there did not exist a complete parallel relationship between RGA-based groups and blast resistance-based groups, five out of six varieties with broad spectrum or durable resistance repeatedly fell into same group. This result suggested that application of three primer pairs, viz. RGA1 and RGA2 （both designed from the LRR region of rice Xa21 gene） and RGA3 （designed from the LRR region of tobacco N gene） contributed to better evaluation of the germplasms for their resistance responses to rice blast.展开更多
Genetic diversity of commercial and local rice cultivars in Yunnan Province was studied using the resistance gene analogue (RGA) based on resistance gene conserved sequences. The RGA analysis of 137 cultivars was cond...Genetic diversity of commercial and local rice cultivars in Yunnan Province was studied using the resistance gene analogue (RGA) based on resistance gene conserved sequences. The RGA analysis of 137 cultivars was conducted by PCR amplification using three primers, i.e. S1/AS3, XLRR for/XLRR rev, and Pto-kinl/Pto-kin2, respectively. The results showed that both Indica and Japonica cultivars were genetically highly diverse. All cultivars were divided into 3 lineages according to the DNA band data at 96% dissimilarity, and into 20 lineages at 60% dissimilarity. The lineages were related to their genetic background and blast disease resistance with only a few exceptions. The RGA data can be useful in rice production by mixed-planting of different cultivars in the field and breeding of resistance cultivars by selecting different parental cultivars with great genetic diversity.展开更多
Plants have developed a complicated defense mechanism during evolution to resist the harmful pathogens they encountered.The mechanism involves the interaction of the plant resistance(R)
Nucleos(t)ide analogues(NA) are a breakthrough in the treatment and management of chronic hepatitis B.NA could suppress the replication of hepatitis B virus(HBV) and control the progression of the disease.However,drug...Nucleos(t)ide analogues(NA) are a breakthrough in the treatment and management of chronic hepatitis B.NA could suppress the replication of hepatitis B virus(HBV) and control the progression of the disease.However,drug resistance caused by their long-term use becomes a practical problem,which influences the long-term outcomes in patients.Liver transplantation is the only choice for patients with HBV-related end-stage liver disease.But,the recurrence of HBV after transplantation often caused by the development of drug resistance leads to unfavorable outcomes for the recipients.Recently,the multi-drug resistance(MDR) has become a common issue raised due to the development and clinical application of a variety of NA.This may complicate the antiviral therapy and bring poorly prognostic outcomes.Although clinical evidence has suggested that combination therapy with different NA could effectively reduce the viral load in patients with MDR,the advent of new antiviral agents with high potency and high genetic barrier to resistance brings hope to antiviral therapy.The future of HBV researches relies on how toprevent the MDR occurrence and develop reasonable and effective treatment strategies.This review focuses on the diagnostic and therapeutic progress in MDR caused by the anti-HBV NA and describes some new research progress in this field.展开更多
基金supported by the National High Technology Research Development Program of China (Grant No.2002AA245041)
文摘DNA fragments of 43 rice varieties were amplified with 11 pairs of primers designed based on resistance gene analogue （RGA） of plants, and the blast resistance of the varieties was identified by inoculation with 33 isolates of Magnaporthe grisea collected from Yunnan Province, China. Clustering results revealed a significant correlation between the blast resistance and DNA bands with a correlation coefficient of 0.6117 （α=0.01）, indicating that the resistance analysis based on RGA-PCR clustering analysis coincided with that based on inoculation. The correlation coefficients, ranging from 0.1701 to 0.535, however, depended on the primers. Five pairs of primers, S1/AS3, S1 INV/S2 INV, XLRR For/XLRR Rev, Pto-Kinl IN/Pto-Kin2 IN, and NLRR For/NLRR Rev might be applied for blast resistance identification in consideration of their band numbers and polymorphisms, and their correlation coefficients with blast resistance were 0.5305, 0.4898, 0.4059, 0.3719 and 0.3524, respectively. Besides, indica and japonica rice except two highly susceptible varieties, CO39 and Lijiangxintuanheigu could be well classified by the 11 pairs of primers.
基金Science Foundation for Post-Doctortoral Work Station of Hunan Yahua Seeds Co. Ltd
文摘A total of 21 rice varieties were assayed based on RGA-PCR using six pairs of RGA primers and evaluated for leaf blast resistance in the nursery as well. Cluster analysis showed that the varieties could be classified into five groups either at the similarity threshold of 0.72 for RGA profiles or at 0.80 for leaf blast severities. Although there did not exist a complete parallel relationship between RGA-based groups and blast resistance-based groups, five out of six varieties with broad spectrum or durable resistance repeatedly fell into same group. This result suggested that application of three primer pairs, viz. RGA1 and RGA2 （both designed from the LRR region of rice Xa21 gene） and RGA3 （designed from the LRR region of tobacco N gene） contributed to better evaluation of the germplasms for their resistance responses to rice blast.
基金supported by the National 863Project(AA211091)the Natural Science Foundation of China(30160048)Yunnan Agricultural University.
文摘Genetic diversity of commercial and local rice cultivars in Yunnan Province was studied using the resistance gene analogue (RGA) based on resistance gene conserved sequences. The RGA analysis of 137 cultivars was conducted by PCR amplification using three primers, i.e. S1/AS3, XLRR for/XLRR rev, and Pto-kinl/Pto-kin2, respectively. The results showed that both Indica and Japonica cultivars were genetically highly diverse. All cultivars were divided into 3 lineages according to the DNA band data at 96% dissimilarity, and into 20 lineages at 60% dissimilarity. The lineages were related to their genetic background and blast disease resistance with only a few exceptions. The RGA data can be useful in rice production by mixed-planting of different cultivars in the field and breeding of resistance cultivars by selecting different parental cultivars with great genetic diversity.
文摘Plants have developed a complicated defense mechanism during evolution to resist the harmful pathogens they encountered.The mechanism involves the interaction of the plant resistance(R)
文摘Nucleos(t)ide analogues(NA) are a breakthrough in the treatment and management of chronic hepatitis B.NA could suppress the replication of hepatitis B virus(HBV) and control the progression of the disease.However,drug resistance caused by their long-term use becomes a practical problem,which influences the long-term outcomes in patients.Liver transplantation is the only choice for patients with HBV-related end-stage liver disease.But,the recurrence of HBV after transplantation often caused by the development of drug resistance leads to unfavorable outcomes for the recipients.Recently,the multi-drug resistance(MDR) has become a common issue raised due to the development and clinical application of a variety of NA.This may complicate the antiviral therapy and bring poorly prognostic outcomes.Although clinical evidence has suggested that combination therapy with different NA could effectively reduce the viral load in patients with MDR,the advent of new antiviral agents with high potency and high genetic barrier to resistance brings hope to antiviral therapy.The future of HBV researches relies on how toprevent the MDR occurrence and develop reasonable and effective treatment strategies.This review focuses on the diagnostic and therapeutic progress in MDR caused by the anti-HBV NA and describes some new research progress in this field.
