National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing 210095, China.
Plant Cell. 2022 Aug 25;34(9):3301-3318. doi: 10.1093/plcell/koac169.
Strigolactones (SLs) constitute a class of plant hormones that regulate many aspects of plant development, including repressing tillering in rice (Oryza sativa). However, how SL pathways are regulated is still poorly understood. Here, we describe a rice mutant dwarf and high tillering1 (dht1), which exhibits pleiotropic phenotypes (such as dwarfism and increased tiller numbers) similar to those of mutants defective in SL signaling. We show that DHT1 encodes a monocotyledon-specific hnRNP-like protein that acts as a previously unrecognized intron splicing factor for many precursor mRNAs (pre-mRNAs), including for the SL receptor gene D14. We find that the dht1 (DHT1I232F) mutant protein is impaired in its stability and RNA binding activity, causing defective splicing of D14 pre-mRNA and reduced D14 expression, and consequently leading to the SL signaling-defective phenotypes. Overall, our findings deepen our understanding of the functional diversification of hnRNP-like proteins and establish a connection between posttranscriptional splicing and SL signaling in the regulation of plant development.
独脚金内酯（SLs）是一类植物激素，调控着植物发育的许多方面，包括抑制水稻分蘖。然而，SL 途径如何被调控仍知之甚少。在这里，我们描述了一个水稻矮化多分蘖突变体 dwarf and high tillering1（dht1），它表现出与 SL 信号缺陷突变体相似的多效表型（如矮化和分蘖数增加）。我们表明，DHT1 编码一个单子叶特异性 hnRNP 样蛋白，作为许多前体 mRNA（pre-mRNAs）的先前未被识别的内含子剪接因子，包括 SL 受体基因 D14。我们发现 dht1（DHT1I232F）突变蛋白在其稳定性和 RNA 结合活性方面受损，导致 D14 前体 mRNA 的剪接缺陷和 D14 表达减少，从而导致 SL 信号缺陷表型。总的来说，我们的研究结果加深了我们对 hnRNP 样蛋白功能多样化的理解，并在植物发育调控中建立了转录后剪接和 SL 信号之间的联系。
