水稻颖壳发育基因AGL1的图位克隆与功能分析

doi:10.16819/j.1001-7216.2026.250909

摘要/Abstract

摘要：

【目的】水稻颖壳发育直接影响籽粒形态、授粉效率、产量与品质。本研究通过鉴定水稻颖壳发育相关突变体，对突变性状基因进行定位克隆，阐明目标基因调控颖壳发育的分子调控机理，可为水稻分子育种提供理论参考。【方法】利用EMS诱变粳稻品种SN9816获得agl1突变体。通过石蜡切片、扫描电镜观察颖壳及花器官形态结构，碘-碘化钾染色法测定花粉活力。利用图位克隆技术对AGL1进行定位，对候选基因测序，同时分析目标基因的保守性和多样性。采用Foss谷物分析仪测定糙米品质参数。【结果】与野生型SN9816相比，突变体agl1的外稃弯曲程度更大，纵向长度没有变化，内稃向内凹陷，内、外稃宽度明显缩小，外稃极大程度包裹住内稃。突变体agl1的浆片形态异常，雌蕊增大，雄蕊排列紊乱；通过测定花粉活性发现，agl1的花粉活性降低，导致结实率下降。利用图位克隆的方法将AGL1定位在2号染色体标记Indel4与Indel5之间，物理距离为68.7 kb。对区间内的7个ORF (open reading frames)测序，发现LOC_Os02g56610在突变体中发生一个单碱基突变，该基因编码一个DUF640结构域蛋白。DUF640家族在水稻中具有保守的ALOG结构域和多样的表达调控元件，其突变可能不仅调控花器官形态建成，在稻米品质中还具有重要作用。米质测定结果表明，糙米蛋白质与游离脂肪酸含量升高，直链淀粉与总淀粉含量降低，导致食味品质下降。【结论】AGL1 基因是调控水稻颖壳发育和米质的关键因子，其功能缺失影响了稃壳形态建成，降低花粉活力，并可能干扰了籽粒灌浆过程，导致产量与品质双双劣变。

关键词: 水稻畸形颖壳, 籽粒形态, 花粉活性, 图位克隆, 食味品质, DUF640家族

Abstract:

【Objective】Rice lemma and palea development directly affects grain shape, pollination efficiency, yield and quality. This study identified mutants related to rice glume development, mapped and cloned the causal genes, and elucidated the molecular mechanisms by which the target genes regulate glume development, providing theoretical references for rice molecular breeding. 【Methods】The agl1 mutant was obtained by EMS mutagenesis of japonica cultivar SN9816. Paraffin sectioning and scanning electron microscopy were used to observe the morphology of glumes and floral organs; pollen viability was assessed by I₂-KI staining. Map-based cloning delimited AGL1, candidate genes were sequenced, and conservation and diversity of the target gene were analyzed. A Foss grain analyzer was used to measure brown-rice quality parameters.【Results】Compared with the wild-type SN9816, agl1 showed more strongly curved lemmas with unchanged longitudinal length, inwardly sunken paleae, and significantly narrowed lemma and palea; the lemma almost completely enclosed the palea. agl1 displayed abnormal lodicules, enlarged pistils and disordered stamens. Pollen activity and seed-setting rate were reduced. AGL1 was fine-mapped to a 68.7-kb interval between Indel4 and Indel5 on chromosome 2. Sequencing seven ORFs in this region revealed a single-nucleotide mutation in LOC_Os02g56610, which encodes a DUF640-domain protein. The DUF640 family in rice harbors a conserved ALOG domain and diverse regulatory elements, suggesting roles in both floral morphogenesis and grain quality. Quality analysis showed increased brown-rice protein and free fatty acid content but decreased amylose and total starch content, leading to poorer eating quality. 【Conclusion】The AGL1 gene functions as a pivotal regulator of rice lemma and palea development and grain quality; its loss-of-function disrupts hull morphogenesis, compromises pollen viability, and likely perturbs the grain-filling process, resulting in the concomitant deterioration of both yield and grain quality.

Key words: aberrant rice lemma, grain shape, pollen viability, map-based cloning, eating quality, DUF640 family

冯莆淋, 杨绮文, 吴佳益, 范鸣谦, 程艳双, 邱忠华, 郭然, 陈温福, 王嘉宇. 水稻颖壳发育基因AGL1的图位克隆与功能分析[J]. 中国水稻科学, 2026, 40(5): 607-617.

FENG Pulin, YANG Qiwen, WU Jiayi, FAN Mingqian, CHENG Yanshuang, QIU Zhonghua, GUO Ran, CHEN Wenfu, WANG Jiayu. Map-based Cloning and Functional Characterization of AGL1, a Gene Regulating Lemma and Palea Development in Rice[J]. Chinese Journal OF Rice Science, 2026, 40(5): 607-617.

图/表 9

图1 SN9816和agl1 突变体的表型和粒型 A: 抽穗期的植株表型; B: 抽穗期穗部表型; C: 成熟期穗部表型; D和E: 抽穗期颖壳; F和G: 成熟期籽粒; H和I: 成熟期糙米; le: 外稃; pa: 内稃。

Fig. 1. Phenotype and grain type of SN9816 and agl1 A, Plant phenotype at the heading stage; B, Panicle phenotype during heading stage; C, Phenotype of the mature panicle; D and E, Glumes at heading stage; F and G, Mature grains; H and I, Mature brown rice; le, Lemma; pa, Palea.

图2 SN9816与突变体agl1的穗部性状误差线为平均值±标准差；** P < 0.01。下同

Fig. 2. Panicle traits of SN9816 and mutant agl1 The error line is the mean ± standard deviation. ** P < 0.01. The same below

图3 SN9816(A、C)与突变体agl1(B、D)的石蜡切片观察

Fig. 3. Paraffin section observation of SN9816(A、C) and mutant agl1(B、D)

图4 SN9816(A)与突变体agl1(B)的扫描电子显微镜观察

Fig. 4. Scanning electron microscopic observation of SN9816(A) and mutant agl1(B)

图5 野生型SN9816(A)和突变体agl1(B)的花粉活力

Fig. 5. Pollen viability of wild type SN9816(A) and mutant agl1(B)

图6 水稻AGL1基因的定位和克隆

Fig. 6. Localization and cloning of the AGL1 gene in rice

图7 DUF640不同物种间系统进化树

Fig. 7. Phylogenetic tree among different species of DUF640

图8 水稻DUF640家族基因及编码蛋白的系统发育与结构分析 A: DUF640水稻系统进化树; B: DUF640的保守基序; C: DUF640的保守结构域; D: DUF640启动子顺式作用元件; E: DUF640的基因结构。

Fig. 8. Phylogenetic and structural analysis of the DUF640 family genes and encoded proteins in rice A, Rice phylogenetic tree of DUF640; B, DUF640 conservative motif; C, Conservative domain of DUF640; D, Starter cis-acting element of DUF640; E, DUF640 gene structure.

图9 野生型SN9816和突变体agl1糙米的谷物分析比较

Fig. 9. Analysis and comparison of brown rice between wild type SN9816 and mutant agl1

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