近日，华中农业大学资源与环境学院植物营养生物学课题组在甘蓝型油菜磷营养高效研究领域取得新的进展，相关成果以“Local and systemic responses conferring acclimation of Brassica napus roots to low phosphorus conditions”为题发表在Journal of Experimental Botany上。
甘蓝型油菜（Brassica napus L.）是我国主要的油料作物之一，需磷量大且对缺磷极为敏感。局部施磷不仅能够减少土壤对磷的固定，还能促进作物根系的生长发育，提高磷的吸收效率，增加产量。根系响应外界磷供应的调控网络包括依赖介质中磷浓度的局部信号调控和依赖植株整体磷水平的系统信号调控。甘蓝型油菜是异源四倍体作物，由于其遗传背景复杂，有关其响应局部供磷的分子机制研究较少。
本研究在琼脂培养体系中利用分根试验模拟土壤局部供磷环境，分析油菜根构型对局部供磷的响应，结果表明局部供磷促进供磷一侧根系二级侧根生长，但抑制缺磷一侧根系二级侧根生长，油菜根构型的改变主要受系统磷信号的调控。利用转录组测序解析了油菜响应磷饥饿的局部和系统信号调控网络，其中参与系统调控的基因显著多于参与局部调控的基因，脱落酸、茉莉酸、活性氧和蔗糖等均参与系统磷饥饿响应。该研究为揭示作物根系可塑性的分子和生理机制提供了新的见解。
博士研究生李亚林为论文第一作者，石磊教授为通讯作者，课题组王创教授、丁广大教授、徐芳森教授、汪社亮副教授、蔡红梅副教授、英国雷丁大学John P. Hammond教授、英国詹姆斯·赫顿研究所Philip J. White教授、澳大利亚塔斯马尼亚大学Sergey Shabala教授、佛山科学技术学院喻敏教授以及我校博士研究生杨鑫宇、刘海疆、汪威也参与了该项研究。该研究得到了国家自然科学基金和国家重点研发计划重点项目的资助。
【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.
论文链接：https://doi.org/10.1093/jxb/erac177
