Huang Ruihua, Liu Mengling, Gong Guanping, Wu Pingzhi, Patra Barunava, Yuan Ling, Qin Hongting, Wang Xiaoxu, Wang Guohe, Liao Huimei, Gao Lu, Yang Chengwei, Li Hongqing, Zhang Shengchun
Guangdong Key Laboratory of Biotechnology for Plant Development, College of Life Sciences, South China Normal University, Guangzhou, 510631, China.
Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
J Integr Plant Biol. 2021 Jul;63(7):1240-1259. doi: 10.1111/jipb.13092. Epub 2021 Jun 2.
Pumilio RNA-binding proteins participate in messenger RNA (mRNA) degradation and translational repression, but their roles in plant development are largely unclear. Here, we show that Arabidopsis PUMILIO PROTEIN24 (APUM24), an atypical Pumilio-homology domain-containing protein, plays an important part in regulating seed maturation, a major stage of plant development. APUM24 is strongly expressed in maturing seeds. Reducing APUM24 expression resulted in abnormal seed maturation, wrinkled seeds, and lower seed oil contents, and APUM24 knockdown resulted in lower levels of WRINKLED 1 (WRI1), a key transcription factor controlling seed oil accumulation, and lower expression of WRI1 target genes. APUM24 reduces the mRNA stability of BTB/POZMATH (BPM) family genes, thus decreasing BPM protein levels. BPM is responsible for the 26S proteasome-mediated degradation of WRI1 and has important functions in plant growth and development. The 3' untranslated regions of BPM family genes contain putative Pumilio response elements (PREs), which are bound by APUM24. Reduced BPM or increased WRI1 expression rescued the deficient seed maturation of apum24-2 knockdown mutants, and APUM24 overexpression resulted in increased seed size and weight. Therefore, APUM24 is crucial to seed maturation through its action as a positive regulator fine-tuning the BPM-WRI1 module, making APUM24 a promising target for breeding strategies to increase crop yields.
Pumilio RNA结合蛋白参与信使核糖核酸（mRNA）的降解和翻译抑制，但其在植物发育中的作用尚不清楚。在此，我们表明拟南芥PUMILIO蛋白24（APUM24），一种含非典型Pumilio同源结构域的蛋白，在调节种子成熟（植物发育的一个主要阶段）中起重要作用。APUM24在成熟种子中强烈表达。降低APUM24的表达会导致种子成熟异常、种子皱缩以及种子油含量降低，并且敲低APUM24会导致WRINKLED 1（WRI1，一种控制种子油积累的关键转录因子）水平降低以及WRI1靶基因表达降低。APUM24降低BTB/POZMATH（BPM）家族基因的mRNA稳定性，从而降低BPM蛋白水平。BPM负责26S蛋白酶体介导的WRI1降解，并且在植物生长发育中具有重要功能。BPM家族基因的3'非翻译区包含推定的Pumilio反应元件（PREs），其与APUM24结合。降低BPM或增加WRI1的表达挽救了apum24 - 2敲低突变体种子成熟缺陷，并且APUM24过表达导致种子大小和重量增加。因此，APUM24通过作为微调BPM - WRI1模块的正向调节因子对种子成熟至关重要，这使得APUM24成为提高作物产量育种策略的一个有前景的靶点。
