CrWOX11调控柑橘体细胞胚胎发生的分子与生理机制

Abstract

Citrus breeding is constrained by a prolonged juvenile phase, nucellar polyembryony, and sterility. Biotechnological tools such as cell engineering and gene editing provide strategies to overcome these barriers, with somatic embryogenesis (SE) serving as a key regeneration pathway. In Ponkan ( Citrus reticulata Blanco), microscopic analysis of callus tissues revealed clear morphological differences: embryonic calli possessed dense cytoplasm, enlarged nuclei, and abundant organelles, whereas nonembryonic calli contained large vacuoles and sparse organelles. Embryonic calli also exhibited higher soluble protein levels, increased activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), and reduced reactive oxygen species (ROS) accumulation. Transcriptome profiling identified 9,076 differentially expressed genes, including CrWOX11 , specifically expressed in embryonic calli. CrWOX11 , a 795-bp gene encoding a 265–amino acid protein, was cloned and overexpressed in four callus lines via Agrobacterium -mediated transformation. Among these, transgenic callus line 1 successfully underwent somatic embryogenesis. Overexpressing lines, compared with the wild type, displayed elevated soluble protein content, enhanced antioxidant enzyme activities, and significantly lower ROS levels. These findings provide a molecular and physiological basis for utilizing the WOX gene family to improve SE and support the development of Citrus and other fruit tree germplasms through biotechnology.