Oomycete, particularly Phytophthora species, causes the most devastating crop diseases, such as potato late blight,and threatens the sustainable crop production worldwide. Our previous studies identified Resistance to...Oomycete, particularly Phytophthora species, causes the most devastating crop diseases, such as potato late blight,and threatens the sustainable crop production worldwide. Our previous studies identified Resistance to Phytophthora parasitica 1(RTP1) as a negative regulator of Arabidopsis resistance to multiple biotrophic pathogens and RTP1 lossof-function plants displayed rapid cell death and reactive oxygen species(ROS) production during early colonization of P. parasitica. In this study, we aim to decipher the mechanism of RTP1-mediated cell death, and identify a member of vaculoar processing enzymes(VPEs), γVPE, playing a role in rtp1-mediated resistance to P. parasitica and cell death occurrence. Our results showed up-regulation of the expression of γVPE as well as increased VPE/caspase 1-like protease activity in P. parasitica-infected rtp1 mutant plants. Besides, we found that the VPE/caspase 1-like protease activity was required for the cell death occurrence in Arabidopsis plants during the infection of P. parasitica as well as rtp1-mediated resistance to P. parasitica. Further pathogenicity assays on either Arabidopsis γvpe mutant plants or leaves of Nicotiana benthamiana with transient overexpression of γVPE demonstrated γVPE could positively affect plant resistance to P. parasitica. Together, our studies suggest that γVPE might function as an important regulator of plant defense and cell death occurrence in response to P. parasitica infection, and VPE/caspase 1-like protease activity is required for rtp1-mediated resistance to P. parasitica.展开更多
AIM: To study the effects of Rheum tanguticum polysaccharide-1 (RTP-1) on ulcerative colitis in rats induced by 2, 4, 6-trinitrophene sulphonic acid (TNBS) and their possible mechanism.METHODS: RTP1 (200 mg@kg-1, ig) ...AIM: To study the effects of Rheum tanguticum polysaccharide-1 (RTP-1) on ulcerative colitis in rats induced by 2, 4, 6-trinitrophene sulphonic acid (TNBS) and their possible mechanism.METHODS: RTP1 (200 mg@kg-1, ig) extracted from Rheum tanguticum Maxim. Ex Regel was administrated to rats with colitis induced by TNBS for 5 d, 7 d, 10 d and 14 d,respectively. The effects of RTP1 and dexamethasone (DX,0.2 mg@kg-1, ig) were contrastively investigated. The MPO level and SOD activity were determined by chromatometry.The expansion and protein expression of CD4+T lymphocytes isolated from colon mucosae and mesenteric lymph nodes of colitis rats were performed by immunohistochemical analysis and Western-blot methods.RESULTS: Treatments of RTP1 (200 mg@kg-1, ig) significantly reduced diarrhea, mortality, colon mass, ulcer areas and MPO level in colon mucosae on days 5, 7, 10 and 14 (5.2±1.4,5.4±0.7, 5.2±1.8, P＜0.05.3.4±0.8, P＜0.01. 16.1±12.1,P＜0.01.31.8±8.6, 17.7±5.3, 12.7±4.1, P＜0.05). The effectsof RTP1 were similar to those noted above in DX group, but there were no immunosupressive effects of DX in RTP-1group, such as body mass loss, thymus and spleen atrophy.The decreased number and down-regulated protein levels of CD4+T cells isolated from the colon of colitis rats treated with RTP1 were found.CONCLUSION: RTP1 shows significantly protective effects but lower side effects on rats with colitis induced by TNBS.The mechanism may be due to the resistance to over expansion of CD4.展开更多
基金supported by the National Natural Science Foundation of China (31872657)the National Key R&D Program of China (2017YFD0200602-2)+2 种基金the Chinese Universities Scientific Fund (2452020146)the China Agriculture Research System (CARS-09)the Program of Introducing Talents of Innovative Discipline to Universities (Project 111) from the State Administration of Foreign Experts Affairs, China (B18042)。
文摘Oomycete, particularly Phytophthora species, causes the most devastating crop diseases, such as potato late blight,and threatens the sustainable crop production worldwide. Our previous studies identified Resistance to Phytophthora parasitica 1(RTP1) as a negative regulator of Arabidopsis resistance to multiple biotrophic pathogens and RTP1 lossof-function plants displayed rapid cell death and reactive oxygen species(ROS) production during early colonization of P. parasitica. In this study, we aim to decipher the mechanism of RTP1-mediated cell death, and identify a member of vaculoar processing enzymes(VPEs), γVPE, playing a role in rtp1-mediated resistance to P. parasitica and cell death occurrence. Our results showed up-regulation of the expression of γVPE as well as increased VPE/caspase 1-like protease activity in P. parasitica-infected rtp1 mutant plants. Besides, we found that the VPE/caspase 1-like protease activity was required for the cell death occurrence in Arabidopsis plants during the infection of P. parasitica as well as rtp1-mediated resistance to P. parasitica. Further pathogenicity assays on either Arabidopsis γvpe mutant plants or leaves of Nicotiana benthamiana with transient overexpression of γVPE demonstrated γVPE could positively affect plant resistance to P. parasitica. Together, our studies suggest that γVPE might function as an important regulator of plant defense and cell death occurrence in response to P. parasitica infection, and VPE/caspase 1-like protease activity is required for rtp1-mediated resistance to P. parasitica.
基金the National Natural Science Foundation of China,No 30100239
文摘AIM: To study the effects of Rheum tanguticum polysaccharide-1 (RTP-1) on ulcerative colitis in rats induced by 2, 4, 6-trinitrophene sulphonic acid (TNBS) and their possible mechanism.METHODS: RTP1 (200 mg@kg-1, ig) extracted from Rheum tanguticum Maxim. Ex Regel was administrated to rats with colitis induced by TNBS for 5 d, 7 d, 10 d and 14 d,respectively. The effects of RTP1 and dexamethasone (DX,0.2 mg@kg-1, ig) were contrastively investigated. The MPO level and SOD activity were determined by chromatometry.The expansion and protein expression of CD4+T lymphocytes isolated from colon mucosae and mesenteric lymph nodes of colitis rats were performed by immunohistochemical analysis and Western-blot methods.RESULTS: Treatments of RTP1 (200 mg@kg-1, ig) significantly reduced diarrhea, mortality, colon mass, ulcer areas and MPO level in colon mucosae on days 5, 7, 10 and 14 (5.2±1.4,5.4±0.7, 5.2±1.8, P＜0.05.3.4±0.8, P＜0.01. 16.1±12.1,P＜0.01.31.8±8.6, 17.7±5.3, 12.7±4.1, P＜0.05). The effectsof RTP1 were similar to those noted above in DX group, but there were no immunosupressive effects of DX in RTP-1group, such as body mass loss, thymus and spleen atrophy.The decreased number and down-regulated protein levels of CD4+T cells isolated from the colon of colitis rats treated with RTP1 were found.CONCLUSION: RTP1 shows significantly protective effects but lower side effects on rats with colitis induced by TNBS.The mechanism may be due to the resistance to over expansion of CD4.
