Spatiotemporal profiles of gene activity in stamen delineate nucleo-cytoplasmic interaction in a male sterile somatic cybrid citrus

Abstract Cytoplasmic male sterility (CMS) has long been used to produce seedless fruits in perennial woody crops like citrus. A male-sterile somatic cybrid citrus (G1 + HBP) was generated by protoplast fusion between a CMS callus parent ‘Guoqing No. 1’ Satsuma mandarin (Citrus unshiu, G1) and fertile mesophyll Hirado Buntan pummelo grandis, HBP). To uncover the mechanism of G1 HBP, we compared transcriptome profiles stamen organ cell types at five stages HBP including initial primordia, enlarged pollen mother cells, tetrads, microspores captured laser microdissection. The showed distinct gene expression profiles. majority genes involved development were differentially expressed, especially CgAP3.2, which downregulated primordia upregulated tetrads with HBP. Jasmonic acid- auxin-related biological processes enriched among expressed content jasmonic acid biosynthesis metabolites higher flower buds anthers In contrast, auxin lower mitochondrial tricarboxylic cycle oxidative phosphorylation meiocytes, microspores, indicating dysfunction mitochondria Taken together, results indicate that malfunction mitochondria-nuclear interaction might cause disorder development, thus lead cybrid.