Plants are regularly exposed to myriads of stress factors that cause tremendous damage to their genetic make-up. To ensure genome stability and survival over several generations under harsher environmental conditions,...Plants are regularly exposed to myriads of stress factors that cause tremendous damage to their genetic make-up. To ensure genome stability and survival over several generations under harsher environmental conditions, plants have evolved a unique mechanism for dealing with DNA damage known as the DNA damage response pathway (DDR). It has been proposed that there may exist a relationship between the DNA damage response pathway and abiotic stress response in plants. To further investigate this relationship, we </span><span><span style="font-family:Verdana;">knocked down the soybean suppressor of gamma response 1 gene (</span><i><span style="font-family:Verdana;">GmSOG1</span></i><span style="font-family:Verdana;">),</span></span><span style="font-family:Verdana;"> a master regulatory gene of the DDR, in soybean plants and subjected the generated transgenic plants to drought stress analysis. Gene expression analysis of the </span><i><span style="font-family:Verdana;">GmSOG1</span></i><span style="font-family:Verdana;"> gene in drought stressed soybean tissues revealed high levels of expression in buds and young leaves. The root lengths and root fresh weights of transgenic soybean plants grown on Murashige and Skoog media supplemented with Gamborg B5 vitamins (MSB5 media) containing 200 mM mannitol for 10 days were significantly lesser than those of drought stressed wild-type plants. Polyethylene glycol (PEG) induced drought stress assay </span><i><span style="font-family:Verdana;">in vivo </span></i><span style="font-family:Verdana;">resulted in significant damage in transgenic plants compared with wild-type plants. Also, the relative expressions of known drought responsive transcription factors such as </span><i><span style="font-family:Verdana;">GmDREB1</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">GmLEA</span></i><span style="font-family:Verdana;"> as well as antioxidation related genes like </span><i><span style="font-family:Verdana;">GmAPX</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">GmCAT </span></i><span style="font-family:Verdana;">were downregulated in transgenic soybean lines relative to wild-type plants. Moreover, wild-type soybean plants accumulated more chlorophyll and less malondialdehyde (MDA) than transgenic lines. A confirmatory experiment in </span><i><span style="font-family:Verdana;">GmSOG1 </span></i><span style="font-family:Verdana;">overexpressing Arabidopsis </span><span style="font-family:Verdana;">plants also showed significantly higher survival rates and anti-oxidation</span><span style="font-family:Verdana;"> enzyme accumulation in drought stressed </span><i><span style="font-family:Verdana;">GmSOG1</span></i><span style="font-family:Verdana;"> overexpressing Arabidopsis lines compared with wild-type plants. These results suggest that the </span><i><span style="font-family:Verdana;">SOG1</span></i><span style="font-family:Verdana;"> gene may play active roles in plant abiotic stress defense.展开更多
Root knot nematodes are top priority nematode pests that significantly constrain agricultural productivity globally especially in developing countries. However, expressing double stranded RNA (dsRNA) of essential nema...Root knot nematodes are top priority nematode pests that significantly constrain agricultural productivity globally especially in developing countries. However, expressing double stranded RNA (dsRNA) of essential nematode genes in susceptible plants is known to confer protection against these pests via RNA silencing. This molecular-based strategy is called host induced gene silencing (HIGS) and the selection of appropriate target nematode gene is critical to its success. In this study, therefore, we focused on root knot nematode PolA1, an essential single copy nuclear gene encoding the largest subunit of RNA polymerase I enzyme and evaluated its effectiveness as a target in conferring nematode resistance on Agrobacterium-mediated transformed tobacco plants. Transgenic tobacco expressing Meloidogyne incognita-specific (MiS) dsRNA of PolA1 gene showed significant reduction in nematode fecundity and multiplication compared to wild type plants in both T0 and T1 generations. T0 plants showed varying degrees of agronomic vigorover WT plants possibly due to varying levels of processed siRNA. However, production of MiS siRNAs in the transgenic plants coupled with significant reduction of PolA1 transcript expression in nematodes feeding on roots of transgenic plants provided evidence of HIGS. Taken together, our results show that PolA1 is a potentially effective target for HIGS-mediated reduction of root knot nematode damage on transgenic tobacco. Given the homology of our target sequence among Meloidogyne species, this protection could be broad range against other root knot nematodes aside M. incognita.展开更多
Wild relatives of crop are key genetic resources serving as diversity reservoirs for crop improvement under changing environments.Rice(Oryza sativa)is one of the most important crops in the world,providing staple food...Wild relatives of crop are key genetic resources serving as diversity reservoirs for crop improvement under changing environments.Rice(Oryza sativa)is one of the most important crops in the world,providing staple food for half of the world's population.Wild rice is thus a critical germplasm resource for sustained global food security,ensuring high production yields,improved quality,and stress resistance in the face of climate change.Wild rice is closely related to domesticated rice and has a rich genetic diversity and exceptional adaptability to extreme environments.It has played a pivotal role in the history of rice hybridization and has become a key resource for rice breeding programs.The identification of wild-type cytoplasmic male sterility resources paved the way for the achievement of the“three lines”goal in hybrid rice,leading to a significant increase in rice yields.In addition,the use of resistance alleles found in wild rice is making rice production more resilient to losses caused by environmental stresses.However,wild rice germplasm resources are threatened due to habitat destruction and other anthropogenic factors.At the same time,the lack of centralized distribution of wild rice has hampered the sharing of basic information on wild rice resources and the utilization and conservation of wild rice in each country,as well as collaboration among scientists.展开更多
文摘Plants are regularly exposed to myriads of stress factors that cause tremendous damage to their genetic make-up. To ensure genome stability and survival over several generations under harsher environmental conditions, plants have evolved a unique mechanism for dealing with DNA damage known as the DNA damage response pathway (DDR). It has been proposed that there may exist a relationship between the DNA damage response pathway and abiotic stress response in plants. To further investigate this relationship, we </span><span><span style="font-family:Verdana;">knocked down the soybean suppressor of gamma response 1 gene (</span><i><span style="font-family:Verdana;">GmSOG1</span></i><span style="font-family:Verdana;">),</span></span><span style="font-family:Verdana;"> a master regulatory gene of the DDR, in soybean plants and subjected the generated transgenic plants to drought stress analysis. Gene expression analysis of the </span><i><span style="font-family:Verdana;">GmSOG1</span></i><span style="font-family:Verdana;"> gene in drought stressed soybean tissues revealed high levels of expression in buds and young leaves. The root lengths and root fresh weights of transgenic soybean plants grown on Murashige and Skoog media supplemented with Gamborg B5 vitamins (MSB5 media) containing 200 mM mannitol for 10 days were significantly lesser than those of drought stressed wild-type plants. Polyethylene glycol (PEG) induced drought stress assay </span><i><span style="font-family:Verdana;">in vivo </span></i><span style="font-family:Verdana;">resulted in significant damage in transgenic plants compared with wild-type plants. Also, the relative expressions of known drought responsive transcription factors such as </span><i><span style="font-family:Verdana;">GmDREB1</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">GmLEA</span></i><span style="font-family:Verdana;"> as well as antioxidation related genes like </span><i><span style="font-family:Verdana;">GmAPX</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">GmCAT </span></i><span style="font-family:Verdana;">were downregulated in transgenic soybean lines relative to wild-type plants. Moreover, wild-type soybean plants accumulated more chlorophyll and less malondialdehyde (MDA) than transgenic lines. A confirmatory experiment in </span><i><span style="font-family:Verdana;">GmSOG1 </span></i><span style="font-family:Verdana;">overexpressing Arabidopsis </span><span style="font-family:Verdana;">plants also showed significantly higher survival rates and anti-oxidation</span><span style="font-family:Verdana;"> enzyme accumulation in drought stressed </span><i><span style="font-family:Verdana;">GmSOG1</span></i><span style="font-family:Verdana;"> overexpressing Arabidopsis lines compared with wild-type plants. These results suggest that the </span><i><span style="font-family:Verdana;">SOG1</span></i><span style="font-family:Verdana;"> gene may play active roles in plant abiotic stress defense.
文摘Root knot nematodes are top priority nematode pests that significantly constrain agricultural productivity globally especially in developing countries. However, expressing double stranded RNA (dsRNA) of essential nematode genes in susceptible plants is known to confer protection against these pests via RNA silencing. This molecular-based strategy is called host induced gene silencing (HIGS) and the selection of appropriate target nematode gene is critical to its success. In this study, therefore, we focused on root knot nematode PolA1, an essential single copy nuclear gene encoding the largest subunit of RNA polymerase I enzyme and evaluated its effectiveness as a target in conferring nematode resistance on Agrobacterium-mediated transformed tobacco plants. Transgenic tobacco expressing Meloidogyne incognita-specific (MiS) dsRNA of PolA1 gene showed significant reduction in nematode fecundity and multiplication compared to wild type plants in both T0 and T1 generations. T0 plants showed varying degrees of agronomic vigorover WT plants possibly due to varying levels of processed siRNA. However, production of MiS siRNAs in the transgenic plants coupled with significant reduction of PolA1 transcript expression in nematodes feeding on roots of transgenic plants provided evidence of HIGS. Taken together, our results show that PolA1 is a potentially effective target for HIGS-mediated reduction of root knot nematode damage on transgenic tobacco. Given the homology of our target sequence among Meloidogyne species, this protection could be broad range against other root knot nematodes aside M. incognita.
文摘Wild relatives of crop are key genetic resources serving as diversity reservoirs for crop improvement under changing environments.Rice(Oryza sativa)is one of the most important crops in the world,providing staple food for half of the world's population.Wild rice is thus a critical germplasm resource for sustained global food security,ensuring high production yields,improved quality,and stress resistance in the face of climate change.Wild rice is closely related to domesticated rice and has a rich genetic diversity and exceptional adaptability to extreme environments.It has played a pivotal role in the history of rice hybridization and has become a key resource for rice breeding programs.The identification of wild-type cytoplasmic male sterility resources paved the way for the achievement of the“three lines”goal in hybrid rice,leading to a significant increase in rice yields.In addition,the use of resistance alleles found in wild rice is making rice production more resilient to losses caused by environmental stresses.However,wild rice germplasm resources are threatened due to habitat destruction and other anthropogenic factors.At the same time,the lack of centralized distribution of wild rice has hampered the sharing of basic information on wild rice resources and the utilization and conservation of wild rice in each country,as well as collaboration among scientists.
