Identification and Functional Analysis of the Rice Vein Development Gene OsLVD1

doi:10.16819/j.1001-7216.2026.251016

Abstract

Abstract: 【Objective】 Photosynthesis is a major determinant of dry matter accumulation in rice, with chlorophyll content and vein density being critical for photosynthetic efficiency. Here, a rice gene regulating chlorophyll content and vein density, OsLVD1, was identified and functionally analyzed.【Method】 OsLVD1 was identified based on homology to maize vein development genes, and its protein features, phylogeny, conserved motifs, and subcellular localization were analyzed bioinformatically. An lvd1 mutant was generated using CRISPR/Cas9, with ZH11 as the wild type. Chlorophyll content, vein density, soluble sugar content, and major agronomic traits were examined. The expression of genes related to chlorophyll metabolism and vein development was analyzed by qRT-PCR.【Result】 OsLVD1 encodes a nuclear localized WRKY transcription factor, and the lvd1 mutation caused a frameshift leading to premature termination. Compared with ZH11, the lvd1 mutant showed reductions of 25.90%, 30.75%, and 27.05% in chlorophyll a, chlorophyll b, and total chlorophyll content, respectively, accompanied by increases in minor vein density and bulliform cell number. Plant height was reduced and growth duration was slightly delayed, whereas soluble sugar content, seed setting rate, and thousand grain weight were unaffected. qRT PCR showed that the expression levels of chlorophyll biosynthesis genes OsHEMA1 and OsCHLI were downregulated, while those of the chlorophyll degradation gene OsNYC1 and the vein development gene OsPIN1b were upregulated in the lvd1 mutant. OsLVD1 was predominantly expressed in leaves, with the highest expression at the jointing stage.【Conclusion】 Loss of OsLVD1 resulted in a “low chlorophyll–high vein density” phenotype, which may compensate for reduced photosynthesis by enhancing vein mediated transport and water retention, thereby maintaining yield stability. This study demonstrates a novel role of OsLVD1 in coordinating leaf pigment metabolism and vascular development in rice.

Key words: , Oryza sativa, OsLVD1, chlorophyll content, leaf vein density, WRKY transcription factor, photosynthesis

摘要： 【目的】光合作用决定水稻干物质积累，叶绿素含量和叶脉密度与光合作用密切相关。本研究在水稻中鉴定调控叶绿素含量和叶脉密度的基因OsLVD1，并对其功能进行解析。【方法】通过玉米叶脉发育基因同源比对获得OsLVD1，并利用生物信息学分析其蛋白特性、系统发育关系、信号肽、跨膜结构域、保守结构域及亚细胞定位。通过CRISPR获得lvd1编辑株，以野生型ZH11为对照，测定叶绿素含量、叶脉密度、可溶性糖含量及株高、分蘖数、每穗粒数等主要农艺性状，并通过qRT-PCR分析相关基因的表达水平。【结果】生物信息学分析表明，OsLVD1编码WRKY家族转录因子，定位于细胞核。lvd1因移码突变导致蛋白提前终止。与ZH11相比，lvd1叶绿素a、叶绿素b和总叶绿素分别下降25.90%、30.75%和27.05%，剑叶小脉密度和泡状细胞数目增加。lvd1株高降低且生育期略延迟，但叶片可溶性糖、结实率、千粒重等均无显著差异。qRT-PCR分析表明，lvd1中叶绿素合成相关基因OsHEMA1和OsCHLI的表达显著下调，而叶绿素降解基因OsNYC1及叶脉发育相关基因OsPIN1b表达上调。组织表达分析显示，OsLVD1在叶片中高表达，且在拔节期达到峰值。【结论】OsLVD1功能缺失导致叶绿素含量降低、叶脉密度增加，可能通过增加叶脉密度和改变泡状细胞发育补偿光合产物运输与水分保持，从而维持产量稳定。本研究揭示OsLVD1在叶片色素代谢与维管系统发育中的新功能，为光合结构优化提供理论基础。

关键词: 水稻, OsLVD1, 叶绿素含量, 叶脉密度, WRKY转录因子, 光合作用

QIU Yijie, QI Feiyang, DU Hewei, HUANG Min, LI Manfei. Identification and Functional Analysis of the Rice Vein Development Gene OsLVD1[J]. Chinese Journal OF Rice Science, 2026, 40(4): 447-459.

邱一洁, 齐飞扬, 杜何为, 黄敏, 李曼菲. 水稻叶脉基因OsLVD1的鉴定及功能分析[J]. 中国水稻科学, 2026, 40(4): 447-459.

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