茄子生长素诱导基因SmIAA19的克隆和分析

Cloning and Characterization of IAA Family Gene Sm IAA19 in Eggplant

以茄子单性结实品系‘D-10’为材料,以茄子单性结实差减文库中差异表达的EST片段Z732为依据,采用RT-PCR和RACE技术克隆获得了生长素诱导基因Sm IAA19(登录号KP114221)的c DNA序列。该基因全长为800 bp,开放阅读框为558 bp,编码185个氨基酸。氨基酸序列比对结果表明该基因编码的氨基酸序列具有Aux/IAA基因家族的典型结构域和保守基本序列,在分子进化上与马铃薯距离最近,与番茄处于同一分支。q RT-PCR分析表明,在低温(门茄)和适温(四门斗)条件下,Sm IAA19在单性结实和非单性结实的子房和果实发育过程中均有表达,单性结实品系中的表达量显著高于非单性结实品系,单性结实品系开花当天子房中的表达量最高,非单性结实品系在低温和适温条件下的表达量均保持在较低的水平。IAA含量检测结果表明,在不同结实性茄子品系的果实发育过程中IAA含量的变化趋势基本相同,在果实发育前期含量较高,且在低温(门茄)条件下,不同结实性果实中IAA的含量变化与Sm IAA19基因的表达量变化相一致。Sm IAA19基因可能与茄子的单性结实有关。

A full length c DNA(800 bp)is cloned by RT-PCR and RACE from parthenocarpic fruit of eggplant(Solanum melongena)line D-10,based on the EST Z732 from eggplant parthenocarpic suppression subtractive hybridization library. The cloned gene belongs to IAA family gene(Sm IAA19 accession number KP114221),which contains an open reading frame(558 bp)and encodes a protein of 185 amino acids. The result of amino acid sequence alignment shows that the protein posses typical structure domain and conservative basic sequence of Aux/IAA gene families. The gene is much more close to potatoes in the evolutionary tree,and on the same branch with tomatoes. Real-time PCR was used to analyze the expression pattern of Sm IAA19 in different varieties and growing period. Result of q RT-PCR indicates that Sm IAA19 gene is expressed in ovary and fruit of parthenocarpic and non parthenocarpic eggplant. The expression in parthenocarpy is significantly higher than that of non-parthenocarpy. The highest expression is measured at anthesis day in parthenocarpic ovaries. Sm IAA19 expression quantity keeps at low level in the non-parthenocarpy strain neither the condition of low temperature nor the optimum temperature. The test shows that the change trend of IAA content is basically the same during the development of eggplant fruit in both parthenocarpic fruits and unparthenocarpic fruits,and IAA content is higher at the early stage. The expression of Sm IAA19 gene in the different eggplant strain is consistent with the change of IAA content under the condition of low temperature(the first inflorescence fruit). So this research suggested that Sm IAA19 gene may be associated with the eggplant parthenocarpy.