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Rice sheath blight, caused by Rhizoctonia solani Kihn (R. solani), poses a significant threat to rice production and quality. Autotetraploid rice, developed through chromosome doubling of diploid rice, holds great potential for enhancing biological and yield traits. However, its resistance to sheath blight in the field has remained unclear. In this study, the field resistance of 35 autotetraploid genotypes and corresponding diploids was evaluated across three environments from 2020 to 2021. The booting stage was optimal for inoculating period based on the inoculation and analysis of R. solani at five rice growth stages. We found autotetraploids generally exhibited lower disease scores than diploids, indicating enhanced resistance after chromosome doubling. Among the 35 genotypes, 16 (45.71%) displayed increased resistance, 2 (5.71%) showed decreased resistance, and 17 (48.57%) displayed unstable resistance in different sowing dates. All combinations of the genotype, environment and ploidy, including the genotype-environment-ploidy interaction, contributed significantly to field resistance. Chromosome doubling increased sheath blight resistance in most genotypes, but was also dependent on the genotype-environment interaction. To elucidate the enhanced resistance mechanism, RNA-seq revealed autotetraploid recruited more down-regulated differentially expressed genes (DEGs), additionally, more resistance-related DEGs, were down-regulated at 24 h post inoculation in autotetraploid versus diploid. The ubiquinone/terpenoid quinone and diterpenoid biosynthesis pathways may play key roles in ploidy-specific resistance mechanisms. In summary, our findings shed light on the understanding of sheath blight resistance mechanisms in autotetraploid rice. [ABSTRACT FROM AUTHOR]

Chloroplasts and mitochondria, descendants of ancient prokaryotes via endosymbiosis, occupy a pivotal position in plant growth and development due to their intricate connections with the nuclear genome. Genes encoded by the nuclear genome but relocated to or being functional within these organelles are commonly referred as organelle-targeting nuclear genes (ONGs). These genes are essential for maintaining cytonuclear coordination, thereby determining the stability of the life cycle. While molecular function and cytonuclear coordination of some endosymbiosis-derived ONGs (E-ONGs) have been extensively studied, the evolutionary history and characteristics from a more widespread range of non-endosymbiosis-derived ONGs (NE-ONGs) remain largely enigmatic. In this study, we focused on 12 representative species within the Poaceae family to systematically identify NE-ONGs and investigated their evolutionary history and functional significance on a phylogenetic timescale. Upon aligning these 12 species' evolutionary histories, we observed the following phenomena: (i) an exploration of NE-ONGs between the BOP and PACMAD clades unveiled dynamic compositions, potentially influencing their photosynthetic divergence; (ii) the majority of the abundant species-specific NE-ONGs exist in a single-copy status, and functional enrichment analysis further underscored their specialized roles, which could be crucial for species adaptation; and (iii) comparative analyses between plasmid- and mitochondria-related NE-ONGs (pNE-ONGs and mNE-ONGs) revealed a prevalence of pNE-ONGs, indicating tighter control for chloroplast function in Poaceae. In summary, this study offers novel insights into the cytonuclear co-evolutionary dynamics in Poaceae speciation and draws attention to crop improvement by using NE-ONGs. [ABSTRACT FROM AUTHOR]