近日，華中農業(yè)大學資源與環(huán)境學院植物營養(yǎng)生物學課題組在甘藍型油菜磷營養(yǎng)高效研究領域取得新的進展，相關成果以“Local and systemic responses conferring acclimation of Brassica napus roots to low phosphorus conditions”為題發(fā)表在Journal of Experimental Botany上。

 

　　甘藍型油菜（Brassica napus L.）是我國主要的油料作物之一，需磷量大且對缺磷極為敏感。局部施磷不僅能夠減少土壤對磷的固定，還能促進作物根系的生長發(fā)育，提高磷的吸收效率，增加產量。根系響應外界磷供應的調控網(wǎng)絡包括依賴介質中磷濃度的局部信號調控和依賴植株整體磷水平的系統(tǒng)信號調控。甘藍型油菜是異源四倍體作物，由于其遺傳背景復雜，有關其響應局部供磷的分子機制研究較少。

 

　　本研究在瓊脂培養(yǎng)體系中利用分根試驗模擬土壤局部供磷環(huán)境，分析油菜根構型對局部供磷的響應，結果表明局部供磷促進供磷一側根系二級側根生長，但抑制缺磷一側根系二級側根生長，油菜根構型的改變主要受系統(tǒng)磷信號的調控。利用轉錄組測序解析了油菜響應磷饑餓的局部和系統(tǒng)信號調控網(wǎng)絡，其中參與系統(tǒng)調控的基因顯著多于參與局部調控的基因，脫落酸、茉莉酸、活性氧和蔗糖等均參與系統(tǒng)磷饑餓響應。該研究為揭示作物根系可塑性的分子和生理機制提供了新的見解。

 

　　博士研究生李亞林為論文第一作者，石磊教授為通訊作者，課題組王創(chuàng)教授、丁廣大教授、徐芳森教授、汪社亮副教授、蔡紅梅副教授、英國雷丁大學John P. Hammond教授、英國詹姆斯·赫頓研究所Philip J. White教授、澳大利亞塔斯馬尼亞大學Sergey Shabala教授、佛山科學技術學院喻敏教授以及我校博士研究生楊鑫宇、劉海疆、汪威也參與了該項研究。該研究得到了國家自然科學基金和國家重點研發(fā)計劃重點項目的資助。

 

　　【英文摘要】

 

　　Due to the non-uniform distribution of inorganic phosphate （Pi） in the soil, plants modify their root architecture to improve acquisition of this nutrient. In this study, a split-root system was employed to assess the nature of local and systemic signals that modulate root architecture of Brassica napus grown with non-uniform Pi availability. Lateral root （LR） growth was regulated systemically by non-uniform Pi distribution, by increasing the second-order LR （2°LR） density in compartments with high Pi supply but decreasing it in compartments with low Pi availability. Transcriptomic profiling identified groups of genes regulated, both locally and systemically, by Pi starvation. The number of systemically induced genes was greater than the number of genes locally induced, and included genes related to abscisic acid （ABA） and jasmonic acid （JA） signalling pathways, reactive oxygen species （ROS） metabolism, sucrose, and starch metabolism. Physiological studies confirmed the involvement of ABA, JA, sugars, and ROS in the systemic Pi starvation response. Our results reveal the mechanistic basis of local and systemic responses of B. napus to Pi starvation and provide new insights into the molecular and physiological basis of root plasticity.

 

　　論文鏈接：https://doi.org/10.1093/jxb/erac177