Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, CC 14, S2125ZAA Zavalla, Argentina; CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, CC 14, S2125ZAA Zavalla, Argentina.
Cátedra de Genética, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, CC 14, S2125ZAA Zavalla, Argentina; CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, CC 14, S2125ZAA Zavalla, Argentina.
Plant Sci. 2014 Jul;224:144-50. doi: 10.1016/j.plantsci.2014.04.018. Epub 2014 May 6.
Acetohydroxyacid synthase (AHAS) is the target site of several herbicides and catalyses the first step in the biosynthesis of branched chain amino acid. Three genes coding for AHAS catalytic subunit (ahas1, ahas2 and ahas3) have been reported for sunflower. The aim of this work was to study the expression pattern of ahas genes family and AHAS activity in sunflower (Helianthus annuus L.). Different organs (leaves, hypocotyls, roots, flowers and embryos) were evaluated at several developmental stages. The transcriptional profile was studied through RT-qPCR. The highest expression for ahas1 was shown in leaves, where all the induced and natural gene mutations conferring herbicide resistance were found. The maximal expression of ahas2 and ahas3 occurred in immature flowers and embryos. The highest AHAS activity was found in leaves and immature embryos. Correlation analysis among ahas gene expression and AHAS activity was discussed. Our results show that differences in ahas genes expression are tissue-specific and temporally regulated. Moreover, the conservation of multiple AHAS isoforms in sunflower seems to result from different expression requirements controlled by tissue-specific regulatory mechanisms at different developmental stages.
乙酰羟酸合酶（AHAS）是几种除草剂的靶标位点，催化支链氨基酸生物合成的第一步。已经报道了向日葵中有 3 个编码 AHAS 催化亚基（ahas1、ahas2 和 ahas3）的基因。本研究旨在研究向日葵ahas 基因家族的表达模式和 AHAS 活性。在不同的发育阶段评估了不同的器官（叶片、下胚轴、根、花和胚胎）。通过 RT-qPCR 研究了转录谱。ahas1 的表达最高的是叶片，其中所有诱导和自然基因突变赋予了除草剂抗性。ahas2 和 ahas3 的最大表达发生在未成熟的花和胚胎中。AHAS 活性最高的是叶片和未成熟的胚胎。讨论了 ahas 基因表达与 AHAS 活性之间的相关性分析。我们的结果表明，ahas 基因表达的差异是组织特异性和时间调节的。此外，向日葵中多个 AHAS 同工酶的保守性似乎是由不同发育阶段组织特异性调节机制控制的不同表达需求导致的。
