Rice zinc finger protein DST enhances grain production through controlling Gn1a/OsCKX2 expression
Rice zinc finger protein DST enhances grain production through controlling Gn1a/OsCKX2 expression
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水稻锌指蛋白 DST 通过控制 Gn1a/OsCKX2 表达提高谷物产量
DOI：
10.1073/pnas.1300359110
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发表时间：
2013-02-19
影响因子：
11.1
通讯作者：
Li, Chuanyou
中科院分区：
文献类型：
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作者：
Li, Shuyu;Zhao, Bingran;Li, Chuanyou
植物激素细胞分裂素（CK）正调控茎尖分生组织（SAM）的活性和功能，SAM是决定种子产量的主要参数。水稻（Oryza sativa L.）Gn 1a/OsCKX 2（Grain number 1a/Cytokinoxidase 2）基因编码一种细胞分裂素氧化酶，是水稻粒数改良的主要数量性状基因。然而，OsCKX 2在植物中的表达调控的分子机制仍然是难以捉摸的。在这里，我们报告，锌指转录因子耐旱耐盐（DST）直接调节OsCKX 2在生殖分生组织的表达。OsCKX 2的DST定向表达调节SAM中CK的积累，因此控制生殖器官的数量。我们确定，DST基因的半显性等位基因DSTreg 1，扰乱DST定向调控OsCKX 2的表达和提高CK水平的生殖SAM，导致分生组织的活动增加，增强穗分枝，并随之增加的粒数。重要的是，DSTreg 1等位基因提供了一种方法来金字塔Gn 1a依赖和Gn 1a独立的粮食生产的影响。我们的研究表明，DST作为一种独特的生殖分生组织活性的调节剂，可能有助于促进水稻和其他小粒谷物籽粒产量的遗传提高。
The phytohormone cytokinin (CK) positively regulates the activity and function of the shoot apical meristem (SAM), which is a major parameter determining seed production. The rice (Oryza sativa L.) Gn1a/OsCKX2 (Grain number 1a/Cytokinin oxidase 2) gene, which encodes a cytokinin oxidase, has been identified as a major quantitative trait locus contributing to grain number improvement in rice breeding practice. However, the molecular mechanism of how the expression of OsCKX2 is regulated in planta remains elusive. Here, we report that the zinc finger transcription factor DROUGHT AND SALT TOLERANCE (DST) directly regulates OsCKX2 expression in the reproductive meristem. DST-directed expression of OsCKX2 regulates CK accumulation in the SAM and, therefore, controls the number of the reproductive organs. We identify that DSTreg1, a semidominant allele of the DST gene, perturbs DST-directed regulation of OsCKX2 expression and elevates CK levels in the reproductive SAM, leading to increased meristem activity, enhanced panicle branching, and a consequent increase of grain number. Importantly, the DSTreg1 allele provides an approach to pyramid the Gn1a-dependent and Gn1a-independent effects on grain production. Our study reveals that, as a unique regulator of reproductive meristem activity, DST may be explored to facilitate the genetic enhancement of grain production in rice and other small grain cereals.