人类命运共同体研究的三重视域评析

人类命运共同体是当代国际视域中最重要的时代性议题之一,在全球治理、共同体构建、文明形态变革等不同层面都具有崭新的世界历史意义。首先,人类命运共同体是直面当下全球治理体系中存在的问题而提出的,它超越了零和博弈与霸权治理的思维定式,确立了合作共赢与共同治理的新型体系和法治、善治、共治的具体方略,具有显著的对外战略意义。其次,人类命运共同体致力于构筑一种主体与共同体相统一的共生系统。它是一种对全新的共同体的积极建构,而非对现存资本主义共同体的被动接受,对整个世界秩序的当代转型具有重要的推动作用。最后,人类命运共同体真实地切中各国人民生存发展的基本诉求,突破欧洲文明中心论的禁锢和宰制,根植于中国独特的文明基因和发展实际,吸纳人类现代性文明成果,开启了一种新的文明形态,蕴含着人类生存方式变革的文明意义。

Tonoplast-associated calcium signaling regulates manganese homeostasis in Arabidopsis

Manganese(Mn)is an essential micronutrient in plants.However,excessive Mn absorption in acidic and waterlogged soils can lead to Mn toxicity.Despite their essential roles in Mn homeostasis,transcriptional and post-transcriptional modifications of Mn transporters remain poorly understood.Here,we demonstrated that high-Mn stress induces an obvious Ca^(2+) signature in Arabidopsis.We identified four calcium-dependent protein kinases,CPK4/5/6/11,that interact with the tonoplast-localized Mn and iron(Fe)transporter MTP8 in vitro and in vivo.The cpk4/5/6/11 quadruple mutant displayed a dramatic high-Mn-sensitive phenotype similar to that of the mtp8 mutant.CPKs phosphorylated the N-terminal domain of MTP8 primarily at the Ser31 and Ser32 residues.Transport assays combined with multiple physiological experiments on phospho-dead variant MTP8^(S31/32A)and phospho-mimetic variant MTP8^(S31/32D)plants under different Mn and Fe conditions suggested that Ser31 and Ser32 are crucial for MTP8 function.In addition,genetic analysis showed that CPKs functioned upstream of MTP8.In summary,we identified a tonoplast-associated calcium signaling cascade that orchestrates Mn homeostasis and links Mn toxicity,Ca^(2+) signaling,and Mn transporters.These findings provide new insight into Mn homeostasis mechanisms and Ca^(2+) signaling pathways in plants,providing potential targets for engineering heavy metal toxicity-tolerant plants.

Ca^(2+)-dependent successive phosphorylation of vacuolar transporter MTP8 by CBL2/3-CIPK3/9/26 and CPK5 is critical for manganese homeostasis in Arabidopsis

Manganese(Mn)is an essential micronutrient for all living organisms.However,excess Mn supply that can occur in acid or waterlogged soils has toxic effects on plant physiology and development.Although a variety of Mn transporter families have been characterized,we have only a rudimentary understanding of how these transporters are regulated to uphold and adjust Mn homeostasis in plants.Here,we demonstrate that two calcineurin-B-like proteins,CBL2/3,and their interacting kinases,CIPK3/9/26,are key regulators of plant Mn homeostasis.Arabidopsis mutants lacking CBL2 and 3 or their interacting protein kinases CIPK3/9/26 exhibit remarkably high Mn tolerance.Intriguingly,CIPK3/9/26 interact with and phosphorylate the tonoplast-localized Mn and iron(Fe)transporter MTP8 primarily at Ser35,which is conserved among MTP8 proteins from various species.Mn transport complementation assays in yeast combined with multiple physiological assays indicate that CBL-CIPK-mediated phosphorylation of MTP8 negatively regulates its transport activity from the cytoplasm to the vacuole.Moreover,we show that sequential phosphorylation of MTP8,initially at Ser31/32 by the calcium-dependent protein kinase CPK5 and subsequently at Ser35 by CIPK26,provides an activation/deactivation fine-tuning mechanism for differential regulation of Mn transport.Collectively,our findings define a two-tiered calcium-controlled mechanism for dynamic regulation of Mn homeostasis under conditions of fluctuating Mn supply.