Hou Dan, Li Ling, Ma Tengfei, Pei Jialong, Zhao Zhongyu, Lu Mengzhu, Wu Aimin, Lin Xinchun
State Key Laboratory of Subtropical Silviculture, Zhejiang A & F University, Lin'an, 311300, Hangzhou, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, 510642, Guangzhou, China.
Hortic Res. 2021 Jun 1;8(1):133. doi: 10.1038/s41438-021-00557-4.
Bamboo is known for its edible shoots and beautiful texture and has considerable economic and ornamental value. Unique among traditional flowering plants, many bamboo plants undergo extensive synchronized flowering followed by large-scale death, seriously affecting the productivity and application of bamboo forests. To date, the molecular mechanism of bamboo flowering characteristics has remained unknown. In this study, a SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1)-like gene, BoMADS50, was identified from Bambusa oldhamii. BoMADS50 was highly expressed in mature leaves and the floral primordium formation period during B. oldhamii flowering and overexpression of BoMADS50 caused early flowering in transgenic rice. Moreover, BoMADS50 could interact with APETALA1/FRUITFULL (AP1/FUL)-like proteins (BoMADS14-1/2, BoMADS15-1/2) in vivo, and the expression of BoMADS50 was significantly promoted by BoMADS14-1, further indicating a synergistic effect between BoMADS50 and BoAP1/FUL-like proteins in regulating B. oldhamii flowering. We also identified four additional transcripts of BoMADS50 (BoMADS50-1/2/3/4) with different nucleotide variations. Although the protein-CDS were polymorphic, they had flowering activation functions similar to those of BoMADS50. Yeast one-hybrid and transient expression assays subsequently showed that both BoMADS50 and BoMADS50-1 bind to the promoter fragment of itself and the SHORT VEGETATIVE PHASE (SVP)-like gene BoSVP, but only BoMADS50-1 can positively induce their transcription. Therefore, nucleotide variations likely endow BoMADS50-1 with strong regulatory activity. Thus, BoMADS50 and BoMADS50-1/2/3/4 are probably important positive flowering regulators in B. oldhamii. Moreover, the functional conservatism and specificity of BoMADS50 and BoMADS50-1 might be related to the synchronized and sporadic flowering characteristics of B. oldhamii.
竹子以其可食用的笋和优美的质地而闻名，具有可观的经济和观赏价值。在传统开花植物中，许多竹子植物会经历广泛的同步开花，随后大规模死亡，这严重影响了竹林的生产力和应用。迄今为止，竹子开花特性的分子机制仍然未知。在本研究中，从绿竹中鉴定出一个CONSTANS1过表达抑制因子（SOC1）样基因BoMADS50。BoMADS50在绿竹开花期间的成熟叶和花原基形成期高表达，并且BoMADS50的过表达导致转基因水稻提前开花。此外，BoMADS50在体内可与APETALA1/FRUITFULL（AP1/FUL）样蛋白（BoMADS14-1/2、BoMADS15-1/2）相互作用，并且BoMADS14-1显著促进了BoMADS50的表达，进一步表明BoMADS50与BoAP1/FUL样蛋白在调控绿竹开花方面具有协同作用。我们还鉴定出BoMADS50的另外四个转录本（BoMADS50-1/2/3/4），它们具有不同的核苷酸变异。尽管蛋白质编码序列是多态的，但它们具有与BoMADS50相似的开花激活功能。酵母单杂交和瞬时表达分析随后表明，BoMADS50和BoMADS50-1均与自身及SHORT VEGETATIVE PHASE（SVP）样基因BoSVP的启动子片段结合，但只有BoMADS50-1能够正向诱导它们的转录。因此，核苷酸变异可能赋予BoMADS50-1强大的调控活性。因此，BoMADS50和BoMADS50-1/2/3/4可能是绿竹中重要的正向开花调节因子。此外，BoMADS50和BoMADS50-1的功能保守性和特异性可能与绿竹的同步和零星开花特性有关。
