Haider Imran, Yunmeng Zhang, White Fred, Li Changsheng, Incitti Roberto, Alam Intikhab, Gojobori Takashi, Ruyter-Spira Carolien, Al-Babili Salim, Bouwmeester Harro J
Plant Hormone Biology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
Division of Biological and Environmental Science and Engineering, Center for Desert Agriculture, The BioActives Lab, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.
Plant J. 2023 Apr;114(2):355-370. doi: 10.1111/tpj.16140. Epub 2023 Feb 28.
Phosphorus (P) is a major element required for plant growth and development. To cope with P shortage, plants activate local and long-distance signaling pathways, such as an increase in the production and exudation of strigolactones (SLs). The role of the latter in mitigating P deficiency is, however, still largely unknown. To shed light on this, we studied the transcriptional response to P starvation and replenishment in wild-type rice and a SL mutant, dwarf10 (d10), and upon exogenous application of the synthetic SL GR24. P starvation resulted in major transcriptional alterations, such as the upregulation of P TRANSPORTER, SYG1/PHO81/XPR1 (SPX) and VACUOLAR PHOSPHATE EFFLUX TRANSPORTER. Gene Ontology (GO) analysis of the genes induced by P starvation showed enrichment in phospholipid catabolic process and phosphatase activity. In d10, P deficiency induced upregulation of genes enriched for sesquiterpenoid production, secondary shoot formation and metabolic processes, including lactone biosynthesis. Furthermore, several genes induced by GR24 treatment shared the same GO terms with P starvation-induced genes, such as oxidation reduction, heme binding and oxidoreductase activity, hinting at the role that SLs play in the transcriptional reprogramming upon P starvation. Gene co-expression network analysis uncovered a METHYL TRANSFERASE that displayed co-regulation with known rice SL biosynthetic genes. Functional characterization showed that this gene encodes an enzyme catalyzing the conversion of carlactonoic acid to methyl carlactonoate. Our work provides a valuable resource to further studies on the response of crops to P deficiency and reveals a tool for the discovery of SL biosynthetic genes.
磷（P）是植物生长发育所需的主要元素。为应对磷短缺，植物会激活局部和长距离信号通路，比如独角金内酯（SLs）的产生和分泌增加。然而，后者在缓解磷缺乏方面的作用仍很大程度上未知。为阐明这一点，我们研究了野生型水稻和一个SL突变体dwarf10（d10）在磷饥饿和补充过程中的转录反应，以及在施加合成SL GR24后的转录反应。磷饥饿导致了主要的转录变化，如磷转运蛋白、SYG1/PHO81/XPR1（SPX）和液泡磷酸盐外排转运蛋白的上调。对磷饥饿诱导基因的基因本体（GO）分析表明，这些基因在磷脂分解代谢过程和磷酸酶活性方面富集。在d10中，磷缺乏诱导了富含倍半萜类化合物产生、次生芽形成和代谢过程（包括内酯生物合成）的基因上调。此外，GR24处理诱导的几个基因与磷饥饿诱导的基因具有相同的GO术语，如氧化还原、血红素结合和氧化还原酶活性，这暗示了SLs在磷饥饿时转录重编程中所起的作用。基因共表达网络分析发现了一个与已知水稻SL生物合成基因共调控的甲基转移酶。功能表征表明，该基因编码一种催化卡拉可酸转化为甲基卡拉可酸的酶。我们的工作为进一步研究作物对磷缺乏的反应提供了宝贵资源，并揭示了一种发现SL生物合成基因的工具。
