CWMV-CP1 target gene and bar selection gene were co-transferred into commercial wheat variety of Yangmai158 by particle bombardment. In total, 145 resistant plants to 3 -5 mg L-1 Bialaphos were obtained, 21 plants wer...CWMV-CP1 target gene and bar selection gene were co-transferred into commercial wheat variety of Yangmai158 by particle bombardment. In total, 145 resistant plants to 3 -5 mg L-1 Bialaphos were obtained, 21 plants were identified to be positive in T0 generation by PCR-Southern test, and the transformation frequency had 0.99%. T1 plants were further tested by PCR and Southern hybridization. Results demonstrated that the alien resistance gene had been integrated into the wheat genome. The segregation ratio of CP1+ to CP1- in T1 generation was 1.0 to 1. 3, and didn't agree with Mendelian rule. RT-PCR result from T2 plants showed that the alien gene CWMV-CP1 had stable expression in wheat genetic background.展开更多
<div style="text-align:justify;"> <em>Citrus tristeza virus</em> (CTV) is an important citrus pathogen causing considerable economic loss to citrus production. Knowledge on genetic evolutio...<div style="text-align:justify;"> <em>Citrus tristeza virus</em> (CTV) is an important citrus pathogen causing considerable economic loss to citrus production. Knowledge on genetic evolutionary of the CTV population in China remains limited. In this study, 1439 samples were collected from nine citrus-producing areas of China. The coat protein (CP) genes of CTV were amplified by RT-PCR, and sequenced to analyze the genetic evolution. Analysis of the base composition showed an AU preference pattern, with the GC content was lower than AU content. Nine CTV populations were clustered into one clade in neighbor-joining (NJ) tree, indicative of a close phylogenetic relationship among the populations in China. Analysis of molecular variation (AMOVA) revealed that 77.72% genetic variations of CTV populations were observed among populations, with an <em>F</em><sub>ST</sub> value of 0.223. The values of <em>d<sub>N</sub>/d<sub>S</sub></em> and neutrality test of <em>CP</em> gene were ranged from 0.016 to 0.082 and -1.377 to 1.456, respectively, the results suggesting that all of nine CTV populations were relatively constantly maintained under purifying selection. Our study demonstrated the genetic characteristics and molecular evolution relationship of CTV populations in China, and provided a theoretical basis for scientific control of CTV. </div>展开更多
Yam mosaic virus (YMV), a Potyvirus, is a highly destructive pathogen of yam accounting for yield losses up to 40%. Apart from causing significant reduction in tuber size and quality, it restricts international exchan...Yam mosaic virus (YMV), a Potyvirus, is a highly destructive pathogen of yam accounting for yield losses up to 40%. Apart from causing significant reduction in tuber size and quality, it restricts international exchange of germplasms. It thus becomes crucial to get resistant or at least virus-free planting materials for farmers. This study was aimed at inducing resistance to YMV in tobacco by RNA silencing. An RNAi construct containing 161 bp fragment of <span style="font-family:Verdana;">YMV-coat protein (CP) </span><span style="font-family:Verdana;">gene was developed and used to produce transgenic tobacco lines expressing </span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;"> derived </span><span style="font-family:Verdana;">double stranded RNA (dsRNA)</span><span style="font-family:""><span style="font-family:Verdana;"> via </span><i><span style="font-family:Verdana;">Agrobacterium</span></i><span style="font-family:Verdana;">-mediated transformation. Of the eight T</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> transgenic lines inoculated with YMV, six (L1, L2, L3, L5, L7 and L8) showed immunity to YMV as no symptoms were detected, whereas two (L4 and L10) exhibited high resistance with mild symptoms limited to inoculation portions. No virus could be detected in uninoculated new leaves of the transgenic lines after RT-PCR and qPCR analyses of </span></span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">The presence of small interfering RNAs in transgenic</span><span style="font-family:MinionPro-Capt;"> </span><span style="font-family:Verdana;">lines after virus challenge indicates</span><span style="font-family:Verdana;"> that the resistance was acquired through RNA silencing.</span>展开更多
基金Thig study was supported by Europe Confederation International Cooperation with Developing Countries(ECINCO)Program(IC18-CT96-0049)Chinese“863”Program(2001-AA212111).
文摘CWMV-CP1 target gene and bar selection gene were co-transferred into commercial wheat variety of Yangmai158 by particle bombardment. In total, 145 resistant plants to 3 -5 mg L-1 Bialaphos were obtained, 21 plants were identified to be positive in T0 generation by PCR-Southern test, and the transformation frequency had 0.99%. T1 plants were further tested by PCR and Southern hybridization. Results demonstrated that the alien resistance gene had been integrated into the wheat genome. The segregation ratio of CP1+ to CP1- in T1 generation was 1.0 to 1. 3, and didn't agree with Mendelian rule. RT-PCR result from T2 plants showed that the alien gene CWMV-CP1 had stable expression in wheat genetic background.
文摘<div style="text-align:justify;"> <em>Citrus tristeza virus</em> (CTV) is an important citrus pathogen causing considerable economic loss to citrus production. Knowledge on genetic evolutionary of the CTV population in China remains limited. In this study, 1439 samples were collected from nine citrus-producing areas of China. The coat protein (CP) genes of CTV were amplified by RT-PCR, and sequenced to analyze the genetic evolution. Analysis of the base composition showed an AU preference pattern, with the GC content was lower than AU content. Nine CTV populations were clustered into one clade in neighbor-joining (NJ) tree, indicative of a close phylogenetic relationship among the populations in China. Analysis of molecular variation (AMOVA) revealed that 77.72% genetic variations of CTV populations were observed among populations, with an <em>F</em><sub>ST</sub> value of 0.223. The values of <em>d<sub>N</sub>/d<sub>S</sub></em> and neutrality test of <em>CP</em> gene were ranged from 0.016 to 0.082 and -1.377 to 1.456, respectively, the results suggesting that all of nine CTV populations were relatively constantly maintained under purifying selection. Our study demonstrated the genetic characteristics and molecular evolution relationship of CTV populations in China, and provided a theoretical basis for scientific control of CTV. </div>
文摘Yam mosaic virus (YMV), a Potyvirus, is a highly destructive pathogen of yam accounting for yield losses up to 40%. Apart from causing significant reduction in tuber size and quality, it restricts international exchange of germplasms. It thus becomes crucial to get resistant or at least virus-free planting materials for farmers. This study was aimed at inducing resistance to YMV in tobacco by RNA silencing. An RNAi construct containing 161 bp fragment of <span style="font-family:Verdana;">YMV-coat protein (CP) </span><span style="font-family:Verdana;">gene was developed and used to produce transgenic tobacco lines expressing </span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;"> derived </span><span style="font-family:Verdana;">double stranded RNA (dsRNA)</span><span style="font-family:""><span style="font-family:Verdana;"> via </span><i><span style="font-family:Verdana;">Agrobacterium</span></i><span style="font-family:Verdana;">-mediated transformation. Of the eight T</span><sub><span style="font-family:Verdana;">1</span></sub><span style="font-family:Verdana;"> transgenic lines inoculated with YMV, six (L1, L2, L3, L5, L7 and L8) showed immunity to YMV as no symptoms were detected, whereas two (L4 and L10) exhibited high resistance with mild symptoms limited to inoculation portions. No virus could be detected in uninoculated new leaves of the transgenic lines after RT-PCR and qPCR analyses of </span></span><span style="font-family:Verdana;">YMV-coat protein (CP)</span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">The presence of small interfering RNAs in transgenic</span><span style="font-family:MinionPro-Capt;"> </span><span style="font-family:Verdana;">lines after virus challenge indicates</span><span style="font-family:Verdana;"> that the resistance was acquired through RNA silencing.</span>
