Drought-induced proline is mainly synthesized in leaves and transported to roots in watermelon under water deficit

Proline accumulation has been shown to occur in plants in response to various environmental stresses.Although proline metabolismrelated genes have been functionally characterized,the inter-organ transport of proline in stressed plants remains unclear.In this study,free proline was detected with significant accumulations in the roots,stems,and leaves of watermelon drought-tolerant germplasm M08 and drought-susceptible line Y34 under drought stress.Expression profiling and enzyme activity measurements revealed that ClP5CS1 gene,rather than its paralog ClP5CS2,mainly contributes to the proline synthesis in leaves via the Glu pathway.Additionally,over-expression of the ClP5CS genes significantly enhanced the drought tolerance of transgenic Arabidopsis lines.Furthermore,we confirmed that proline is mainly synthesized in leaves and transported to roots in watermelon under drought stress.Transcriptome and expression analyses revealed that the genes involved in proline metabolism exhibited different expression levels.Specifically,ClP5CS1 was upregulated in leaves and roots,while ClP5CS2 was downregulated under drought stress.Also,415 and 362 differently expressed TFs were identified in roots and leaves,respectively,with the majority upregulated in the former.Ultimately,a model for proline metabolism was proposed.The findings of this study provided new insights into the biosynthesis,transport,and regulatory mechanism of drought-induced proline in plants.

Cancer cachexia:Focus on cachexia factors and inter-organ communication

Cancer cachexia is a multi-organ syndrome and closely related to changes in signal communication between organs,which is mediated by cancer cachexia factors.Cancer cachexia factors,being the general name of inflammatory factors,circulating proteins,metabolites,and microRNA secreted by tumor or host cells,play a role in secretory or other organs and mediate complex signal communication between organs during cancer cachexia.Cancer cachexia factors are also a potential target for the diagnosis and treatment.The pathogenesis of cachexia is unclear and no clear effective treatment is available.Thus,the treatment of cancer cachexia from the perspective of the tumor ecosystem rather than from the perspective of a single molecule and a single organ is urgently needed.From the point of signal communication between organs mediated by cancer cachexia factors,finding a deeper understanding of the pathogenesis,diagnosis,and treatment of cancer cachexia is of great significance to improve the level of diagnosis and treatment.This review begins with cancer cachexia factors released during the interaction between tumor and host cells,and provides a comprehensive summary of the pathogenesis,diagnosis,and treatment for cancer cachexia,along with a particular sight on multi-organ signal communication mediated by cancer cachexia factors.This summary aims to deepen medical community’s understanding of cancer cachexia and may conduce to the discovery of new diagnostic and therapeutic targets for cancer cachexia.

The plant vascular systemⅠ:From resource allocation,inter-organ communication and defense,to evolution of the monocot cambium

In recent years, considerable attention has been paid to exploring the complex gene regulatory networks involved in the development of the plant vascular system. Such information is crucial to our understanding of the molecular and cellular events which give rise to the integrated tissues of the xylem and phloem, leading to the formation of structurally continuous conduits that interconnect various organs of the plant. Vascular development begins in the embryo to form progenitor cells, and upon germination, these progenitor cells and their decedents in the shoot and root meristems will form phloem and xylem, and the cambium.

The plant vascular system Ⅱ:From resource allocation,inter-organ communication and defense,to evolution of the monocot cambium

In this Special Issue, a focus is placed on the role of the xylem as an essential conduit for the long-distance delivery of water and mineral nutrients from the soil to the vegetative （above-ground） regions of the plant. Xylem cells destined to form tracheids or vessel members, which will make up the conduit for this water and mineral transport from the roots to the shoots, undergo apoptosis, a process of programmed cell death.

Blood-derived factors to brain communication in brain diseases

Brain diseases,mainly including acute brain injuries,neurodegenerative diseases,and mental disorders,have posed a significant threat to human health worldwide.Due to the limited regenerative capability and the existence of the blood–brain barrier,the brain was previously thought to be separated from the rest of the body.Currently,various cross-talks between the central nervous system and peripheral organs have been widely described,including the brain-gut axis,the brain-liver axis,the brain-skeletal muscle axis,and the brain-bone axis.Moreover,several lines of evidence indicate that leveraging systemic biology intervention approaches,including but not limited to lifestyle interventions,exercise,diet,blood administration,and peripheral immune responses,have demonstrated a significant influence on the progress and prognosis of brain diseases.The advancement of innovative proteomic and transcriptomic technologies has enriched our understanding of the nuanced interplay between peripheral organs and brain diseases.An array of novel or previously underappreciated blood-derived factors have been identified to play pivotal roles in mediating these communications.In this review,we provide a comprehensive summary of blood-to-brain communication following brain diseases.Special attention is given to the instrumental role of blood-derived signals,positing them as significant contributors to the complex process of brain diseases.The insights presented here aim to bridge the current knowledge gaps and inspire novel therapeutic strategies for brain diseases.

Chrono-exercise: Time-of-day-dependent physiological responses to exercise

Exercise is an effective strategy to prevent and improve obesity and related metabolic diseases.Exercise increases the metabolic demand in the body.Although many of the metabolic health benefits of exercise depend on skeletal muscle adaptations,exercise exerts many of its metabolic effects through the liver,adipose tissue,and pancreas.Therefore,exercise is the physiological state in which inter-organ signaling is most important.By contrast,circadian rhythms in mammals are associated with the regulation of several physiological and biological functions,including body temperature,sleep-wake cycle,physical activity,hormone secretion,and metabolism,which are controlled by clock genes.Glucose and lipid tolerance reportedly exhibit diurnal variations,being lower in the evening than in the morning.Therefore,the effects of exercise on substrate metabolism at different times of the day may differ.In this review,the importance of exercise timing considerations will be outlined,incorporating a chrono-exercise perspective.