Integrated cytological, physiological, and comparative transcriptome profiling analysis of the male sterility mechanism of Xinli No.7

Xinli No.7, a progeny of Korla Fragrant Pear, is an early-maturing, high-quality pear cultivar. As a dominant variety in Chinas pear-producing regions, it holds significant agricultural importance. Investigating its male sterility mechanisms is critical for hybrid breeding and large-scale cultivation. Integrated cytological, physiological, and transcriptomic analyses were conducted to compare dynamic differences between MS Xinli No.7 and male-fertile MF, Korla Fragrant Pear plants during anther development. Cytological observations revealed that pollen abortion in Xinli No.7 initiates at the tetrad stage, driven by microspore vacuolation, abnormal tapetum degradation, and insufficient nutrient supply. Physiological assays demonstrated excessive reactive oxygen species accumulation, lower proline content, higher malondialdehyde levels, and reduced activities of antioxidant enzymes peroxidase and catalase in MS plants. Comparative transcriptomics identified 283 coexpressed differentially expressed genes . Functional enrichment linked these DEGs to ROS scavenging pathways: Galactose metabolism, Ascorbate and aldarate metabolism, Arginine and proline metabolism, Fatty acid degradation, Pyruvate metabolism, and Flavonoid bio-synthesis. qRTPCR validated the expression patterns of key DEGs in these pathways. A core transcriptome-mediated MS network was proposed, implicating accelerated ROS generation and dysregulated tapetal programmed cell death. These findings pro-vide theoretical insights into the molecular mechanisms of male sterility in Xinli No.7, supporting future genetic and breeding applications.