Twenty-nine years following the breakthrough discovery that a single-gene mutation of daf-2 doubles Caenorhabditis elegans lifespan, it remains unclear where this insulin/IGF-1 receptor gene is expressed and where it acts to regulate ageing. Using knock-in fluorescent reporters, we determined that daf-2 and its downstream transcription factor daf-16 are expressed ubiquitously. Using tissue-specific targeted protein degradation, we determined that intracellular DAF-2-to-DAF-16 signaling in the intestine plays a major role in lifespan regulation, while that in the hypodermis, neurons, and germline plays a minor role. Notably, intestine-specific loss of DAF-2 activates DAF-16 in and outside the intestine, causes almost no adverse effects on development and reproduction, and extends lifespan by 94% in a way that partly requires non-intestinal DAF-16. Consistent with intestine supplying nutrients to the entire body, evidence from this and other studies suggests that altered metabolism, particularly down-regulation of protein and RNA synthesis, mediates longevity by reduction of insulin/IGF-1 signaling.

Background The transcription factors of WRKY genes play essential roles in plant growth, stress responses, and metabolite biosynthesis. Erigeron breviscapus, a traditional Chinese herb, is abundant in flavonoids and has been used for centuries to treat cardiovascular and cerebrovascular diseases. However, the WRKY transcription factors that regulate flavonoid biosynthesis in E. breviscapus remain unknown.Results In this study, genome-wide characterization of WRKY genes in E. breviscapus was conducted to predict 75 EbWRKY transcription factors using phylogenetic, gene structure, and conserved motif analyses. In addition, the chromosomal location of each EbWRKY gene was analyzed. RNA sequencing showed that several EbWRKY genes transiently responded to exogenous abscisic acid (ABA), salicylic acid (SA), and gibberellin 3 (GA3) after 4h of treatment. In contrast, the expression of key structural genes involved in flavonoid biosynthesis increased after 4h in GA3 treatment. However, the content of flavonoid metabolites in leaves significantly increased at 12h. The quantitative real-time PCR (qRT-PCR) results showed that the expression patterns of EbWRKY11, EbWRKY30, EbWRKY31, EbWRKY36, and EbWRKY44 transcription factors were similar to those of the 11 structural genes involved in flavonoid biosynthesis.Conclusions This study provides comprehensive information on the regulatory control network of flavonoid accumulation mechanisms, which could contribute to improving the pharmaceutical value of E. breviscapus.