杨树转录因子NF-YB21调节根系发育与抗旱生长的分子机制

干旱胁迫下根系的发育调控对于植物生产力稳定性与环境适应至关重要，但是其分子机制仍知之甚少。我们前期在杨树中鉴定了一个新的调控根系发育的转录因子NF-YB21，干旱与ABA诱导其特异性在根中上调表达，过表达NF-YB21杨树根系生物量、根导管直径、根木质化程度、株高及总生物量都比对照显著增加，根系导水性与植株抗旱性大幅度提高；敲除突变体nf-yb21根系生长、导管发育和株高生长受到严重抑制，对干旱胁迫十分敏感。可见NF-YB21是干旱条件下杨树根系生长与木质部发育的重要调控因子，但是其作用分子机理还不清楚。本项目拟以WT与oxNF-YB21、nf-yb21株系为材料，运用分子遗传学、生物化学、细胞生物学、植物生理学以及多组学等手段深入揭示NF-YB21调控杨树根系生长、导管发育与抗旱生产力的分子机理及调控网络，鉴定调控途径的关键基因，为改良树木抗旱性与提高抗旱生产力提供理论依据和技术支持。

Root development under drought stress is crucial for plant productivity stability and environmental adaptation, but its regulatory molecular mechanisms are still poorly understood. Previously, we have identified a new transcription factor NF-YB21 regulating root development in poplar. Drought and ABA upregulated its expression specificity in the root. Compared with the control, overexpression of PdNF-YB21 in poplar significantly promoted root biomass, root vessel diameter, root lignification degree, plant height and total plant biomass. The root hydraulic conductivity and plant drought resistance were increased substantially in PdNF-YB21 overexpressing poplar; In contrast, the knockout mutant nf-yb21 exhibited inhibited the root growth, vessel development and plant height growth severely, and nf-yb21 was sensitive to drought stress. However, the molecular mechanism by which NF-YB21 regulates root growth and xylem vessel development is still unclear. Using molecular genetics, biochemistry, cell biology, plant physiology, and multiple omics means, the WT, oxNFYB21 and nf-yb21 poplars will be adopted as plant materials in this plan to further reveal the molecular mechanism of oxNFYB21 regulating poplar root growth, xylem vessel development and drought productivity, to reveal its regulatory network, and to identify the key genes in the pathway. Our research will try to provide theoretical basis and technical support for modified trees on drought resistance and drought productivity.