中国农业科学 ›› 2023, Vol. 56 ›› Issue (7): 1248-1259.doi: 10.3864/j.issn.0578-1752.2023.07.004

• 专题:水稻穗发育与产量育种 • 上一篇    下一篇


赵梓钧(), 吴如会(), 王硕, 张君, 游静, 段倩楠, 唐俊, 张新芳, 韦秘, 刘金艳, 李云峰, 何光华, 张婷()   

  1. 西南大学农学与生物科技学院/南方山地农业教育部工程中心,重庆 400715
  • 收稿日期:2022-09-24 接受日期:2022-11-02 出版日期:2023-04-01 发布日期:2023-04-03
  • 联系方式: 赵梓钧,。吴如会,。赵梓钧和吴如会为同等贡献作者。
  • 基金资助:
    国家自然科学基金青年科学基金(31900612); 高校基本科研业务费项目(SWU-KT22041); 国家级大学生创新创业训练计划(202210635082)

Mutation of PDL2 Gene Causes Degeneration of Lemma in the Spikelet of Rice

ZHAO ZiJun(), WU RuHui(), WANG Shuo, ZHANG Jun, YOU Jing, DUAN QianNan, TANG Jun, ZHANG XinFang, WEI Mi, LIU JinYan, LI YunFeng, HE GuangHua, ZHANG Ting()   

  1. College of Agronomy and Biotechnology, Southwest University/Engineering Research Center of South Upland Agriculture, Ministry of Education, Chongqing 400715
  • Received:2022-09-24 Accepted:2022-11-02 Published:2023-04-01 Online:2023-04-03


【目的】 小穗是禾本科植物特有的花器官。在水稻中,小穗作为花序的基本单位和独有结构,对水稻的产量和品质具有重要影响。因此,研究水稻小穗和花器官的发育,为水稻产量和品质的形成提供依据。【方法】 使用甲基磺酸乙酯(ethyl methane sulfonate,EMS)诱变籼稻保持系西农1B,获得2个具有相似突变表型的水稻等位突变体polarity defect of lateral organs 2-1polarity defect of lateral organs 2-2pdl2-1pdl2-2)。由于二者表型相似,选取pdl2-1(命名为pdl2)为材料,通过显微观察和石蜡切片技术分析其小穗突变表型;通过农艺性状考察分析小穗外稃突变对水稻产量的影响;通过图位克隆技术验证PDL2的功能;运用原位杂交技术及实时荧光定量PCR(RT-qPCR)技术分析PDL2的表达模式。【结果】 表型分析结果表明,与野生型相比,pdl2突变体外稃明显变窄,不能与内稃紧密钩合,导致小穗开裂,内轮花器官部分裸露在外,但其雄蕊、雌蕊和浆片的形态和数量均表现正常。进一步的石蜡切片结果表明,突变体外稃硅化细胞和泡状细胞体积、数量的降低,以及维管束间距的减小,是导致pdl2外稃的宽度明显变窄的原因。农艺性状考察表明,pdl2外稃的变化最终引起籽粒呈水滴状,并使得pdl2突变体的结实率和千粒重等产量性状明显下降。遗传分析和图位克隆结果表明,PDL2是一个单隐性核基因,是位于水稻第4染色体的OsDCL4。该基因编码一个Dicer-like蛋白,在水稻ta-siRNA的合成途径中发挥重要作用,并且pdl2突变体是OsDCL4的一个新的弱等位突变。利用原位杂交技术及RT-qPCR技术进行的表达模式分析和基因功能分析结果表明,PDL2在水稻各轮花器官中组成型表达,该基因的突变不会影响水稻花器官特征的形成,但会干扰水稻ta-siRNA合成,影响水稻近-远轴极性建立相关基因的表达,从而导致突变体外稃近-远轴极性建立紊乱。【结论】 水稻外稃退化基因PDL2的突变使得外稃近-远轴极性建立紊乱,影响小穗外稃的发育和产量性状的形成。

关键词: 水稻(Oryza sativa L.), 小穗, 外稃, 图位克隆, 功能分析


【Objective】 Spikelet is a unique floral organ of the grass family. In rice, the spikelet, as the basic unit and unique structure of inflorescence, has an important impact on the yield and quality. Therefore, studying the development of rice spikelets and floral organs can provide the foundation for the formation of rice yield and quality. 【Method】 Two rice allelic mutants, polarity defect of lateral organs 2-1 and polarity defect of lateral organs 2-2 (pdl2-1 and pdl2-2) with similar mutant phenotypes were obtained using Ethyl Methane Sulfonate (EMS) mutagenesis in the indica rice maintenance line Xinong 1B. Because of their phenotypic similarity, pdl2-1 (named pdl2) was selected as the material for further analysis. Microscopic observation and paraffin sectioning techniques were used to analyze their spikelet mutant phenotypes; agronomic trait examination was used to analyze the effect of lemma on rice yield; map-based cloning were used to verify the function of PDL2; in situ hybridization and real-time fluorescence quantitative PCR (RT-qPCR) were used to analyze the expression pattern of PDL2. 【Result】 The results of the phenotypic analysis showed that the lemma of pdl2 mutant was significantly narrower and could not be closely hooked to the palea compared with that of wild type, resulting in spikelet dehiscence and partially exposed inner whorl floral organs. However, the morphology and number of stamens, pistils, and lodicules were normal. Further paraffin section results showed that the reduced volume and number of silicified and vesicular cells in the mutant lemma, as well as the reduced spacing of vascular bundles, were responsible for the significant narrowing of the width of the lemma in pdl2. Agronomic traits examined showed that the mutation in the pdl2 lemma eventually caused the seeds to be teardrop-shaped and resulted in a significant decrease in yield traits such as seed setting rate and 1000-grain weight in the pdl2 mutant. Genetic analysis and map-based cloning showed that PDL2 is a single recessive nuclear gene, which is OsDCL4 gene localized on chromosome 4. PDL2 encodes a Dicer-like protein that plays an essential role in the rice ta-siRNA synthesis pathway, and the pdl2 mutant is a novel weak allelic mutation of OsDCL4 gene. The expression pattern analysis showed that the PDL2 gene was constitutively expressed in all whorls of floral organs. Mutation of PDL2 affected the ta-siRNA synthesis and the expression of genes related to the establishment of adaxial-abaxial polarity, thus leading to the disorder of adaxial-abaxial polarity establishment in the lemma of pdl2. And the characteristics of floral organs were normal. 【Conclusion】 Mutation of lemma degeneration gene PDL2 disrupts the establishment of lemma adaxial-abaxial polarity and affects the development of lemma and the formation of yield traits.

Key words: rice (Oryza sativa L.), spikelet, lemma, map-based cloning, functional analysis