Pascual Laura, Blanca Jose M, Cañizares Joaquin, Nuez Fernado
Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain.
BMC Plant Biol. 2009 May 29;9:67. doi: 10.1186/1471-2229-9-67.
Tomato fruit set is a key process that has a great economic impact on crop production. We employed the Affymetrix GeneChip Tomato Genome Array to compare the transcriptome of a non-parthenocarpic line, UC82, with that of the parthenocarpic line RP75/59 (pat3/pat4 mutant). We analyzed the transcriptome under normal conditions as well as with forced parthenocarpic development in RP75/59, emasculating the flowers 2 days before anthesis. This analysis helps to understand the fruit set in tomato.
Differentially expressed genes were extracted with maSigPro, which is designed for the analysis of single and multiseries time course microarray experiments. 2842 genes showed changes throughout normal carpel development and fruit set. Most of them showed a change of expression at or after anthesis. The main differences between lines were concentrated at the anthesis stage. We found 758 genes differentially expressed in parthenocarpic fruit set. Among these genes we detected cell cycle-related genes that were still activated at anthesis in the parthenocarpic line, which shows the lack of arrest in the parthenocarpic line at anthesis. Key genes for the synthesis of gibberellins and ethylene, which were up-regulated in the parthenocarpic line were also detected.
Comparisons between array experiments determined that anthesis was the most different stage and the key point at which most of the genes were modulated. In the parthenocarpic line, anthesis seemed to be a short transitional stage to fruit set. In this line, the high GAs contends leads to the development of a parthenocarpic fruit, and ethylene may mimic pollination signals, inducing auxin synthesis in the ovary and the development of a jelly fruit.
番茄坐果是一个对作物产量有重大经济影响的关键过程。我们使用Affymetrix基因芯片番茄基因组阵列，比较了非单性结实品系UC82与单性结实品系RP75/59（pat3/pat4突变体）的转录组。我们分析了正常条件下以及RP75/59中强制单性结实发育时的转录组，在开花前2天对花朵进行去雄处理。该分析有助于了解番茄的坐果情况。
使用专为单系列和多系列时间进程微阵列实验分析设计的maSigPro提取差异表达基因。2842个基因在正常心皮发育和坐果过程中表现出变化。其中大多数在开花时或开花后表达发生变化。品系间的主要差异集中在开花阶段。我们发现758个基因在单性结实坐果中差异表达。在这些基因中，我们检测到单性结实品系中在开花时仍被激活的细胞周期相关基因，这表明单性结实品系在开花时缺乏停滞。还检测到在单性结实品系中上调的赤霉素和乙烯合成关键基因。
阵列实验之间的比较确定开花是最不同的阶段，也是大多数基因被调控的关键点。在单性结实品系中，开花似乎是坐果的一个短暂过渡阶段。在该品系中，高赤霉素含量导致单性结实果实的发育，乙烯可能模拟授粉信号，诱导子房内生长素合成并促进果冻状果实的发育。
