Evaluation of novel promoters for vascular tissue-specific gene expression in Populus

Yi An; Xue Jiao; Song Yang; Shiqi Wang; Ningning Chen; Lichao Huang; Cheng Jiang; Mengzhu Lu; Jin Zhang

doi:10.1016/j.plantsci.2024.112083

Evaluation of novel promoters for vascular tissue-specific gene expression in Populus

Plant Sci. 2024 Apr 6:344:112083. doi: 10.1016/j.plantsci.2024.112083. Online ahead of print.

Authors

Yi An¹, Xue Jiao¹, Song Yang¹, Shiqi Wang¹, Ningning Chen¹, Lichao Huang¹, Cheng Jiang¹, Mengzhu Lu¹, Jin Zhang²

Affiliations

¹ State Key Laboratory of Subtropical Silviculture, Sino-Australia Plant Cell Wall Research Centre, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, Zhejiang 311300, China.
² State Key Laboratory of Subtropical Silviculture, Sino-Australia Plant Cell Wall Research Centre, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, Zhejiang 311300, China. Electronic address: zhangj@zafu.edu.cn.

PMID: 38588982
DOI: 10.1016/j.plantsci.2024.112083

Abstract

Due to the extended generation cycle of trees, the breeding process for forest trees tends to be time-consuming. Genetic engineering has emerged as a viable approach to expedite the genetic breeding of forest trees. However, current genetic engineering techniques employed in forest trees often utilize continuous expression promoters such as CaMV 35S, which may result in unintended consequences by introducing genes into non-target tissues. Therefore, it is imperative to develop specific promoters for forest trees to facilitate targeted and precise design and breeding. In this study, we utilized single-cell RNA-Seq data and co-expression network analysis during wood formation to identify three vascular tissue-specific genes in poplar, PP2-A10, PXY, and VNS07, which are expressed in the phloem, cambium/expanding xylem, and mature xylem, respectively. Subsequently, we cloned the promoters of these three genes from '84K' poplar and constructed them into a vector containing the eyGFPuv visual selection marker, along with the 35S mini enhancer to drive GUS gene expression. Transgenic poplars expressing the Pro_PagPP2-A10::GUS, Pro_PagPXY::GUS, and Pro_PagVNS07::GUS constructs were obtained. To further elucidate the tissue specificity of these promoters, we employed qPCR, histochemical staining, and GUS enzyme activity. Our findings not only establish a solid foundation for the future utilization of these promoters to precisely express of specific functional genes in stems but also provide a novel perspective for the modular breeding of forest trees.

Keywords: GUS genes; Poplar; Tissue-specific promoters; Vascular tissue.