Hydathodes are small organs found on the leaf margins of vascular plants which release excess xylem sap through a process called guttation. While previous studies have hinted at additional functions of hydathode in metabolite transport or auxin metabolism, experimental support is limited. We conducted comprehensive transcriptomic, metabolomic and physiological analyses of mature Arabidopsis hydathodes. This study identified 1460 genes differentially expressed in hydathodes compared to leaf blades, indicating higher expression of most genes associated with auxin metabolism, metabolite transport, stress response, DNA, RNA or microRNA processes, plant cell wall dynamics and wax metabolism. Notably, we observed differential expression of genes encoding auxin-related transcriptional regulators, biosynthetic processes, transport and vacuolar storage supported by the measured accumulation of free and conjugated auxin in hydathodes. We also showed that 78% of the total content of 52 xylem metabolites was removed from guttation fluid at hydathodes. We demonstrate that NRT2.1 and PHT1;4 transporters capture nitrate and inorganic phosphate in guttation fluid, respectively, thus limiting the loss of nutrients during this process. Our transcriptomic and metabolomic analyses unveil an organ with its specific physiological and biological identity.
PLANT CELL:湖南大学揭示翻译水平激活JA信号转导的新机制
Jasmonate是调控多重植物生理反应的激素。本研究发现，茉莉酸在通过 3′ untranslated region (3′ UTR)诱导tRNA-binding protein YUELAO 1 (YL1)的翻译。YL1 和YL2协同激活茉莉酸信号转导。YL1还可以通过蛋白质互作诱导 MYC2 transcription factor的表达，这是一个依赖它的 3′ UTR的过程。YL1对茉莉酸信号转导的激活依赖MYC2.
小结：本研究揭示了茉莉酸在翻译水平上通过YL1来激活下游信号转导的机制。
原文：Jasmonate induces translation of the Arabidopsis tRNA-binding protein YUELAO1, which activates MYC2 in jasmonate signaling
