Cytological Observation and RNA-Seq Analyses Reveal miR9564 and Its Target Associated with Pollen Sterility in Autotetraploid Rice

• Published in: Plants (Basel) 2024-06, Vol.13 (11), p.1461
• Main Authors: Lu, Zijun, Huang, Weicong, Zhu, Lianjun, Liang, Guobin, Huang, Yu, Wu, Jinwen, Chen, Rou, Li, Xiang, Liu, Xiangdong
• Format: Article
• Language: English
• Subjects: Anthers; Autotetraploid; Biodiversity; Chromosomes; Comparative analysis; Fertility; Fertilization; Gene expression; Genetic aspects; Haplotypes; Heterosis; Identification and classification; Infertility; Meiosis; MicroRNA; MicroRNAs; miRNA; Overexpression; Pattern analysis; Physiological aspects; Pollen; pollen sterility; polyploid rice; Polyploidy; Ribonucleic acid; Rice; RNA; Seeds; Sterility; Sterility in plants
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants13111461

Understanding the regulation of autotetraploid sterility is essential for harnessing the strong advantages in genomic buffer capacity, biodiversity, and heterosis of autotetraploid rice. miRNAs play crucial roles in fertility regulation, yet information about their reproductive roles and target genes in tetraploid rice remains limited. Here, we used three tetraploid lines, H1 (fertile), HF (fertile), and LF (sterile), to investigate cytological features and identify factors associated with autotetraploid sterility. LF showed abnormal meiosis, resulting in low pollen fertility and viability, ultimately leading to scarce fertilization and a low-seed setting compared to H1 and HF. RNA-seq revealed 30 miRNA-candidate target pairs related to autotetraploid pollen sterility. These pairs showed opposite expression patterns, with differential expression between fertile lines (H1 and HF) and the sterile line (LF). qRT-PCR confirmed that , , and were highly expressed in the anthers of H1 and HF but not in LF, while opposite results were obtained in their targets ( , , and ). Haplotype and expression pattern analyses revealed that was specifically expressed in lines with the same haplotype of (the precursor of ) as LF. Furthermore, the Dual-GFP assay verified that inhibited the fluorescence signal of ARPS-GFP. The over-expression of significantly decreased the seed setting rate (59.10%) and pollen fertility (50.44%) of neo-tetraploid rice, suggesting that plays important roles in autotetraploid pollen sterility. This study provides insights into the cytological characteristic and miRNA expression profiles of tetraploid lines with different fertility, shedding light on the role of miRNAs in polyploid rice.