Max-Planck-Institut für Molekulare Pflanzenphysiologie, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany.
Department of Genetics, University of Potsdam, 14469 Potsdam, Germany.
Plant Physiol. 2021 Mar 15;185(2):352-368. doi: 10.1093/plphys/kiaa034.
KLU, encoded by a cytochrome P450 CYP78A family gene, generates an important-albeit unknown-mobile signal that is distinct from the classical phytohormones. Multiple lines of evidence suggest that KLU/KLU-dependent signaling functions in several vital developmental programs, including leaf initiation, leaf/floral organ growth, and megasporocyte cell fate. However, the interactions between KLU/KLU-dependent signaling and the other classical phytohormones, as well as how KLU influences plant physiological responses, remain poorly understood. Here, we applied in-depth, multi-omics analysis to monitor transcriptome and metabolome dynamics in klu-mutant and KLU-overexpressing Arabidopsis plants. By integrating transcriptome sequencing data and primary metabolite profiling alongside phytohormone measurements, our results showed that cytokinin signaling, with its well-established function in delaying leaf senescence, was activated in KLU-overexpressing plants. Consistently, KLU-overexpressing plants exhibited significantly delayed leaf senescence and increased leaf longevity, whereas the klu-mutant plants showed early leaf senescence. In addition, proline biosynthesis and catabolism were enhanced following KLU overexpression owing to increased expression of genes associated with proline metabolism. Furthermore, KLU-overexpressing plants showed enhanced drought-stress tolerance and reduced water loss. Collectively, our work illustrates a role for KLU in positively regulating leaf longevity and drought tolerance by synergistically activating cytokinin signaling and promoting proline metabolism. These data promote KLU as a potential ideal genetic target to improve plant fitness.
KLU 由细胞色素 P450 CYP78A 家族基因编码，产生一种重要的、尚未可知的移动信号，与经典植物激素不同。多条证据表明，KLU/KLU 依赖性信号在几个重要的发育程序中发挥作用，包括叶片起始、叶片/花器官生长和大孢子母细胞命运。然而，KLU/KLU 依赖性信号与其他经典植物激素之间的相互作用，以及 KLU 如何影响植物生理反应，仍知之甚少。在这里，我们应用深入的多组学分析来监测 klu 突变体和 KLU 过表达拟南芥植物的转录组和代谢组动态。通过整合转录组测序数据和初级代谢物谱分析以及植物激素测量，我们的结果表明，细胞分裂素信号转导，其在延缓叶片衰老方面的作用已得到充分证实，在 KLU 过表达植物中被激活。一致地，KLU 过表达植物表现出明显延迟的叶片衰老和增加的叶片寿命，而 klu 突变体植物表现出早期叶片衰老。此外，由于与脯氨酸代谢相关的基因表达增加，脯氨酸生物合成和分解代谢在 KLU 过表达后增强。此外，KLU 过表达植物表现出增强的耐旱性和减少的水分损失。总之，我们的工作说明了 KLU 通过协同激活细胞分裂素信号和促进脯氨酸代谢来正向调节叶片寿命和耐旱性的作用。这些数据促进了 KLU 作为一个潜在的理想遗传靶标，以提高植物的适应性。
