Mo Jinhui, Liu Yuan, Tan Xiling, Lu Yaoke, Wang Wenlin, Xiong Tao, Liang Kangming, Liao Chunwen, Huang Bingyu, Lu Yuandong, Xu Zeng-Fu, Wang Yi
Key Laboratory of National Forestry and Grassland Administration on Cultivation of Fast‑Growing Timber in Central South China, College of Forestry, Guangxi University, Nanning, China.
Guangxi South Subtropical Agricultural Science Research Institute, Longzhou, China.
Physiol Plant. 2025 Jul-Aug;177(4):e70458. doi: 10.1111/ppl.70458.
Macadamia spp., high-value forest crops, face considerable challenges in increasing yields due to inefficient clonal propagation of superior varieties, which severely limits industrial development. This study focused on the WUSCHEL-related homeobox (WOX) family, which includes key regulators of plant regeneration. We systematically identified the members of the WOX family in four cultivated varieties of the "smooth-shelled" type and in one species of the "rough-shelled" type. We demonstrated the presence of 19 WOX family members in M. integrifolia "GR1." Expression analysis revealed that the WUS clade members MiWOX1b, 4a, and 4b were highly expressed in shoot apices, roots, and calli. Functional validation experiments demonstrated that overexpressing MiWOX1b, 4a, and 4b significantly enhanced de novo root regeneration (DNRR) in Nicotiana benthamiana. The hypocotyls of MiWOX1b- and MiWOX4a-overexpressing N. benthamiana seedlings spontaneously produced ectopic buds on hormone-free Murashige and Skoog medium in a dose-dependent manner, suggesting their involvement in de novo shoot regeneration (DNSR). Transcriptomic analysis further revealed that these genes promoted regeneration by activating auxin biosynthesis genes, such as TAR1 and YUC2/4, and upregulating the regeneration-associated genes GRFs and BBM. Moreover, MiWOX1b-assisted transformation of woody oil crop Plukenetia volubilis resulted in transgenic shoots. These findings highlight the potential of these genes for forest genetic engineering while providing novel insights into the molecular mechanisms of regeneration in woody plants.
澳洲坚果属植物是高价值的林木作物，由于优良品种的克隆繁殖效率低下，在提高产量方面面临巨大挑战，这严重限制了产业发展。本研究聚焦于与WUSCHEL相关的同源异型框（WOX）家族，该家族包含植物再生的关键调控因子。我们系统鉴定了4个“光壳种”栽培品种和1个“粗壳种”品种中的WOX家族成员。我们证明了在澳洲坚果树“GR1”中有19个WOX家族成员。表达分析表明，WUS进化枝成员MiWOX1b、4a和4b在茎尖、根和愈伤组织中高表达。功能验证实验表明，过表达MiWOX1b、4a和4b显著增强了本氏烟草的从头生根再生（DNRR）。过表达MiWOX1b和MiWOX4a的本氏烟草幼苗的下胚轴在无激素的Murashige和Skoog培养基上以剂量依赖的方式自发产生异位芽，表明它们参与了从头芽再生（DNSR）。转录组分析进一步表明，这些基因通过激活生长素生物合成基因（如TARl和YUC2/4）并上调再生相关基因GRFs和BBM来促进再生。此外，MiWOX1b辅助的木本油料作物南美油藤转化产生了转基因芽。这些发现突出了这些基因在林木基因工程中的潜力，同时为木本植物再生的分子机制提供了新的见解。
