TCP4 interacts with HDA6 and regulates flowering and leaf development in Arabidopsis

阿拉伯芥中TCP家族的成員參與在種子萌發、葉片老化等植物生長過程，而Class II的TCP成員則會藉由調控生長中的葉原基(leaf primordia)邊緣細胞分裂程度來影響植物的葉片型態。通過酵母菌雙雜交以及雙分子螢光互補實驗，我們發現HDA6會和許多TCP轉綠因子有交互作用。另外， tcp4突變株會有晚開花的現象。tcp4 與hda6突變株axe1-5的雙突變株tcp4-2/axe1-5比起tcp4 和axe1-5單突變株會有更晚開花的現象，並且葉片捲曲和鋸齒的性狀也更加明顯。而在tcp4，hda6與as1或是與as2的三突變株中，植物的葉片範圍也比單突變或是雙突變株小，葉子的鋸齒亦更明顯。在tcp4 和axe1-5單突變株以及tcp4-2/axe1-5雙突變株中，調控葉片發育的基因KNATM以及開花時間基因FLC，MAF4和MAF5的表現量均會上升。從這些結果我們知道TCP4和HDA6可能會藉由共同調控下游基因來影響阿拉伯芥的開花時間以及葉片型態。TCP transcription factors participate in diverse plant developmental processes such as seed germination and leaf senescence. Class II TCPs influence leaf morphogenesis by regulating cell proliferation at the margins of the developing leaf primordia in Arabidopsis. We found that HDA6 can interact with many TCPs in yeast two-hybrid assays and bimolecular fluorescence complementation assays. In addition, tcp4 mutants have a late flowering phenotype under long day conditions. The double mutant of tcp4 and hda6 (axe1-5), tcp4-2/axe1-5, shows enhanced delayed flowering phenotypes and displays severe serration and curling leaf phenotypes compared to the tcp4 and axe1-5 single mutants. Furthermore, in the triple mutant of tcp4, axe1-5, as1-1 or as2-1, the plant sizes are smaller and their leaves are more serrated compared to tcp4-2/axe1-5 double mutants. The expression of the leaf development regulating gene KNATM and flowering time control genes FLC, MAF4 and MAF5 are increased in tcp4 and axe1-5 mutants compared to wild type. These data suggest that TCP4 and HDA6 might influence the flowering time and leaf development by acting cooperatively to regulate downstream gene expression in Arabidopsis