西南大学魏洪彬小组的研究显示，光敏色素相互作用因子3（PIF3）同源物调控着杨树的茎伸长和木材形成。相关论文于2025年7月7日发表在《遗传学报》杂志上。

研究小组研究了PtoPIF3.1和PtoPIF3.2在绒毛杨（Populthem tomentosa）茎生长和次生木质部发育中的表达模式和参与情况。过表达PtoPIF3.1或PtoPIF3.2均能显著促进茎的纵向生长和木材的径向发育。相反，CRISPR生成的Ptopif3.1和Ptopif3.2突变体表现出相互的表型缺陷。外源生长素的应用部分恢复了Ptopif3.1和Ptopif3.2突变体的表型，而生长素生物合成缺陷突变体Ptoyuc8表现出与Ptopif3突变体相似的发育异常。

进一步分析发现，PtoPIF3s直接结合并激活PtoYUC8和细胞扩增相关基因PtoEXPA1.1/1.2的表达，同时通过生长素介导的信号传导调节形成层分裂和次生木质部发育标志基因（PtoWOX4、PtoANT、PtoCYCD3s和PtoHB7/8）。总之，他们的研究结果确定了PtoPIF3.1/3.2是协调Populthem茎伸长和次生生长的关键调节因子，突出了PIF同源物在草本植物和木本物种之间的功能差异。

据介绍，植物色素相互作用因子（Phytochrome-interacting factors, pif）在草本植物拟南芥（Arabidopsis thaliana）中作为维管模式和木质部分化的负调节因子已被证实，然而，PIF在木本植物次生生长中的调节作用尚不清楚。

附：英文原文

Title: PHYTOCHROME-INTERACTING FACTOR3 (PIF3) orthologs orchestrate stem elongation and wood formation in Populus

Author: Keming Luo, Hongbin Wei

Issue&Volume: 2025/07/07

Abstract: Phytochrome-interacting factors (PIFs) have been established as negative regulators of vascular patterning and xylem differentiation in the herbaceous plant Arabidopsis thaliana, however, PIFs’ regulatory role in secondary growth in woody species remains unclear. Here, we examined the expression patterns and involvement of PtoPIF3.1 and PtoPIF3.2 during stem growth and secondary xylem development in Populus tomentosa. Overexpression of either PtoPIF3.1 or PtoPIF3.2 significantly enhances both longitudinal stem growth and radial wood development. Conversely, CRISPR-generated Ptopif3.1 and Ptopif3.2 mutants exhibit reciprocal phenotypic defects. Exogenous auxin application partially restores the phenotypes of Ptopif3.1 and Ptopif3.2 mutants, and the auxin biosynthesis-deficient mutant Ptoyuc8 exhibits developmental abnormalities similar to those observed in Ptopif3 mutants. Further analysis revealed that PtoPIF3s directly bind to and activate expression of PtoYUC8 and cell expansion-related genes PtoEXPA1.1/1.2, while modulating cambial division and secondary xylem development marker genes (PtoWOX4, PtoANT, PtoCYCD3s, and PtoHB7/8) through auxin-mediated signaling. Together, our findings establish PtoPIF3.1/3.2 as key regulators that coordinate stem elongation and secondary growth in Populus, highlighting the functional divergence of PIF homologs between herbaceous and woody species.

DOI: 10.1016/j.jgg.2025.07.002

Source: https://www.sciencedirect.com/science/article/abs/pii/S1673852725001997