College of Agronomy and Key Laboratory of Physiological Ecology and Genetic Improvement of Food Crops in Henan Province, Henan Agricultural University, Zhengzhou, China.
PLoS One. 2011;6(6):e20621. doi: 10.1371/journal.pone.0020621. Epub 2011 Jun 7.
Modifying plant architecture to increase photosynthesis efficiency and reduce shade avoidance response is very important for further yield improvement when crops are grown in high density. Identification of alleles controlling leaf angle in maize is needed to provide insight into molecular mechanism of leaf development and achieving ideal plant architecture to improve grain yield.
METHODOLOGY/PRINCIPAL FINDINGS: The gene cloning was done by using comparative genomics, and then performing real-time polymerase chain reaction (RT-PCR) analysis to assay gene expression. The gene function was validated by sequence dissimilarity analysis and QTL mapping using a functional cleaved amplified polymorphism (CAP).
The leaf angle is controlled by a major quantitative trait locus, ZmTAC1 (Zea mays L. Leaf Angle Control 1). ZmTAC1 has 4 exons encoding a protein with 263 amino acids, and its domains are the same as those of the rice OsTAC1 protein. ZmTAC1 was found to be located in the region of qLA2 by using the CAP marker and the F(2:3) families from the cross between Yu82 and Shen137. Real-time PCR analysis revealed ZmTAC1 expression was the highest in the leaf-sheath pulvinus, less in the leaf and shoot apical meristem, and the lowest in the root. A nucleotide difference in the 5'-untranslated region (UTR) between the compact inbred line Yu82 ("CTCC") and the expanded inbred line Shen137 ("CCCC") influences the expression level of ZmTAC1, further controlling the size of the leaf angle. Sequence verification of the change in the 5'-UTR revealed ZmTAC1 with "CTCC" was present in 13 compact inbred lines and ZmTAC1 with "CCCC" was present in 18 expanded inbred lines, indicating ZmTAC1 had been extensively utilized in breeding with regard to the improvement of the maize plant architecture.
在高密度种植作物时，改变植物结构以提高光合作用效率和减少遮荫回避反应对于进一步提高产量非常重要。鉴定控制玉米叶片角度的等位基因，有助于深入了解叶片发育的分子机制，并实现理想的植物结构，以提高粮食产量。
方法/主要发现：通过比较基因组学进行基因克隆，然后进行实时聚合酶链反应（RT-PCR）分析以检测基因表达。通过序列相似性分析和功能切割扩增多态性（CAP）的 QTL 作图验证基因功能。
叶片角度受一个主要的数量性状位点 ZmTAC1（玉米叶片角度控制 1）控制。ZmTAC1 有 4 个外显子，编码一个由 263 个氨基酸组成的蛋白质，其结构域与水稻 OsTAC1 蛋白相同。通过 CAP 标记和 Yu82 与 Shen137 杂交的 F2:3 家系，发现 ZmTAC1 位于 qLA2 区域。实时 PCR 分析显示，ZmTAC1 在叶鞘叶枕中的表达最高，在叶片和茎尖分生组织中表达较少，在根中表达最低。Yu82 紧凑型自交系（“CTCC”）和 Shen137 扩展型自交系（“CCCC”）之间 5'-UTR 中的一个核苷酸差异影响 ZmTAC1 的表达水平，进一步控制叶片角度的大小。对 5'-UTR 变化的序列验证表明，13 个紧凑型自交系中存在 ZmTAC1 与“CTCC”，18 个扩展型自交系中存在 ZmTAC1 与“CCCC”，表明 ZmTAC1 在改良玉米植物结构的育种中得到了广泛应用。
