Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberel...Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberellins(GAs)play crucial roles in plant growth,development,and responses to drought stress.Previous studies have shown significant reductions of GA levels in plants under drought stress;however,our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.Here,we show that drought stress can impair the accumulation of bioactive GAs(BGAs),and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.This gene was significantly induced by drought stress and abscisic acid(ABA)treatment,but was suppressed by GA_(3)treatment.PbrGA2ox1-overexpressing transgenic tobacco plants(Nicotiana benthamiana)exhibited enhanced tolerance to dehydration and drought stresses,whereas knock-down of PbrGA2ox1 in pear(Pyrus betulaefolia)by virus-induced gene silencing led to elevated drought sensitivity.Transgenic plants were hypersensitive to ABA,and had a lower BGAs content,enhanced reactive oxygen species(ROS)scavenging ability,and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.However,the opposite effects were observed with PbrGA2ox1 silencing in pear.Moreover,exogenous GA_(3)treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling,resulting in the compromised drought tolerance of pear.In summary,our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress,providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants.展开更多
目的探讨共刺激分子OX40/OX40L在过敏性紫癜(HSP)患儿外周血单个核细胞(PBMC)中的表达及其在过敏性紫癜发病机制中的作用及临床意义。方法选取首次住院的34例HSP患儿作为观察组,另20例健康体检儿童作为对照组。采集分离PBMC,应用逆转录...目的探讨共刺激分子OX40/OX40L在过敏性紫癜(HSP)患儿外周血单个核细胞(PBMC)中的表达及其在过敏性紫癜发病机制中的作用及临床意义。方法选取首次住院的34例HSP患儿作为观察组,另20例健康体检儿童作为对照组。采集分离PBMC,应用逆转录-聚合酶链式反应(RT-PCR)检测OX40、OX40L mRNA的表达,并分析其与24 h尿微量白蛋白(24 h UMA)的相关性。结果 HSP患儿OX40、OX40L mRNA的表达均明显高于对照组,差异有统计学意义(P均<0.01)。24 h UMA增高的HSP患儿OX40、OX40L mRNA的表达均高于24 h UMA正常者,差异均有统计学意义(P均<0.05),且均与24 h UMA呈正相关(P<0.05)。结论过敏性紫癜患儿PBMC的OX40、OX40L mRNA表达有异常增高并与24 h UMA相关。提示OX40、OX40L可能参与了过敏性紫癜的发病,其或许可以作为监测HSP患儿病情及检测早期肾脏损害的免疫学指标。展开更多
基金supported by grants from the China Agriculture Research System(CARS-28-14)the Technical System of Fruit Industry in Anhui Province,China(AHCYTX-10)the Scientific Research Projects for Postgraduates of Anhui Universities,China(YJS20210207).
文摘Drought stress is a devastating natural disaster driven by the continuing intensification of global warming,which seriously threatens the productivity and quality of several horticultural crops,including pear.Gibberellins(GAs)play crucial roles in plant growth,development,and responses to drought stress.Previous studies have shown significant reductions of GA levels in plants under drought stress;however,our understanding of the intrinsic regulation mechanisms of GA-mediated drought stress in pear remains very limited.Here,we show that drought stress can impair the accumulation of bioactive GAs(BGAs),and subsequently identified PbrGA2ox1 as a chloroplast-localized GA deactivation gene.This gene was significantly induced by drought stress and abscisic acid(ABA)treatment,but was suppressed by GA_(3)treatment.PbrGA2ox1-overexpressing transgenic tobacco plants(Nicotiana benthamiana)exhibited enhanced tolerance to dehydration and drought stresses,whereas knock-down of PbrGA2ox1 in pear(Pyrus betulaefolia)by virus-induced gene silencing led to elevated drought sensitivity.Transgenic plants were hypersensitive to ABA,and had a lower BGAs content,enhanced reactive oxygen species(ROS)scavenging ability,and augmented ABA accumulation and signaling under drought stress compared to wild-type plants.However,the opposite effects were observed with PbrGA2ox1 silencing in pear.Moreover,exogenous GA_(3)treatment aggravated the ROS toxic effect and restrained ABA synthesis and signaling,resulting in the compromised drought tolerance of pear.In summary,our results shed light on the mechanism by which BGAs are eliminated in pear leaves under drought stress,providing further insights into the mechanism regulating the effects of GA on the drought tolerance of plants.
文摘目的探讨共刺激分子OX40/OX40L在过敏性紫癜(HSP)患儿外周血单个核细胞(PBMC)中的表达及其在过敏性紫癜发病机制中的作用及临床意义。方法选取首次住院的34例HSP患儿作为观察组,另20例健康体检儿童作为对照组。采集分离PBMC,应用逆转录-聚合酶链式反应(RT-PCR)检测OX40、OX40L mRNA的表达,并分析其与24 h尿微量白蛋白(24 h UMA)的相关性。结果 HSP患儿OX40、OX40L mRNA的表达均明显高于对照组,差异有统计学意义(P均<0.01)。24 h UMA增高的HSP患儿OX40、OX40L mRNA的表达均高于24 h UMA正常者,差异均有统计学意义(P均<0.05),且均与24 h UMA呈正相关(P<0.05)。结论过敏性紫癜患儿PBMC的OX40、OX40L mRNA表达有异常增高并与24 h UMA相关。提示OX40、OX40L可能参与了过敏性紫癜的发病,其或许可以作为监测HSP患儿病情及检测早期肾脏损害的免疫学指标。
