Zhang Jing, Zhang Weixi, Ding Changjun, Zhao Jun, Su Xuehui, Yuan Zhengsai, Chu Yanguang, Huang Qinjun, Su Xiaohua
State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.
State Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.
Plant Cell Environ. 2025 May;48(5):3529-3543. doi: 10.1111/pce.15371. Epub 2025 Jan 9.
Growth heterosis is crucial for Populus deltoides breeding, a key industrial-timber and ecological-construction tree species in temperate regions. However, the molecular mechanisms underlying carbon (C)-nitrogen (N) metabolism coordination in regulating growth heterosis remain unclear. Herein high-hybrids of P. deltoides exhibited high-parent heterosis and mid-parent heterosis in growth traits and key enzymes of C-N metabolism. In hybrids, gene expression patterns were mainly biased toward female parent. Parental contribution to growth heterosis in P. deltoides is differentiation, rather than absolute maternal or paternal dominance contributions. Parental genes were predominantly and dynamically inherited in a non-additive manner, mainly with dominant expression patterns. A total of 44 non-additive genes associated with photosynthetic C fixation, starch and sucrose metabolism, sucrose transport, photorespiration, and nitrogen metabolism coregulated growth heterosis by coordinating C-N metabolism. Growth-regulating factors 4 interacted with DELLA genes to promote growth by enhancing this coordination. Additionally, five critical genes were identified. Briefly, the above genes in high-hybrids improved photosynthesis and N utilisation by regulating carbohydrate accumulation and enzyme activity, while reducing respiratory energy consumption, thereby providing more energy for growth and promoting growth heterosis. Our findings offer new insights and theoretical basis for deep understanding genetic and molecular regulation mechanisms of tree heterosis and its application in precision hybrid breeding.
生长杂种优势对于美洲黑杨育种至关重要，美洲黑杨是温带地区重要的工业用材和生态建设树种。然而，碳（C）-氮（N）代谢协调调控生长杂种优势的分子机制仍不清楚。在此，美洲黑杨高杂种在生长性状以及碳氮代谢关键酶方面表现出高亲杂种优势和中亲杂种优势。在杂种中，基因表达模式主要偏向母本。美洲黑杨亲本对生长杂种优势的贡献在于分化，而非绝对的母本或父本显性贡献。亲本基因主要以非加性方式动态遗传，主要呈现显性表达模式。共有44个与光合碳固定、淀粉和蔗糖代谢、蔗糖转运、光呼吸以及氮代谢相关的非加性基因通过协调碳氮代谢共同调控生长杂种优势。生长调控因子4与DELLA基因相互作用，通过增强这种协调作用来促进生长。此外，还鉴定出5个关键基因。简而言之，高杂种中的上述基因通过调节碳水化合物积累和酶活性来改善光合作用和氮利用，同时降低呼吸能量消耗，从而为生长提供更多能量并促进生长杂种优势。我们的研究结果为深入理解树木杂种优势的遗传和分子调控机制及其在精准杂交育种中的应用提供了新的见解和理论基础。
