The expression of cell proliferation-related genes in early developing flowers is affected by a fruit load reduction in tomato plants
The expression of cell proliferation-related genes in early developing flowers is affected by a fruit load reduction in tomato plants
复制标题
DOI：
10.1093/jxb/erj082
复制
发表时间：
2006-03-01
影响因子：
6.9
通讯作者：
Rothan, C
中科院分区：
文献类型：
--
作者：
Baldet, P;Hernould, M;Rothan, C
源汇器官间光同化分配的变化显著影响果实的发育和大小。在本研究中，比较了低果实负荷（每架1个果实，L1植株）和标准果实负荷（每架5个果实，L5植株）下生长的番茄植株（Solanum lycopersicum L.）的形态、生化和分子水平。果实负荷的减少增加了植物的光同化利用率，并提高了所分析的所有植物器官（根、茎、叶、花和果实）的生长速度。L1植株的花和果尺寸越大，花前子房细胞数量越多。这可能是由于花的生长速度加快，因为其他花的发育参数（时间表和时间过程）没有受到影响。RT-PCR结果显示，CYCB2的转录水平；1 （cyclin）和CDKB2；1（周期蛋白依赖性激酶），两个有丝分裂特异性基因，在花蕾发育早期强烈增加。值得注意的是，CYCD3的转录丰度；1，一种可能参与细胞周期调节的d型周期蛋白，响应有丝分裂信号，在L1花发育的早期阶段也增加了5倍以上。相比之下，被认为是番茄果实细胞分裂负调控因子的fw2.2转录本在花芽发育中明显减少，原位杂交研究证实了这一点。综上所述，这些结果表明，碳水化合物分配的变化可以通过调节细胞增殖相关基因在花发育的早期阶段控制果实的大小。
Changes in photoassimilate partitioning between source and sink organs significantly affect fruit development and size. In this study, a comparison was made of tomato plants (Solanum lycopersicum L.) grown under a low fruit load (one fruit per truss, L1 plants) and under a standard fruit load (five fruits per truss, L5 plants), at morphological, biochemical, and molecular levels. Fruit load reduction resulted in increased photoassimilate availability in the plant and in increased growth rates in all plant organs analysed (root, stem, leaf, flower, and fruit). Larger flower and fruit size in L1 plants were correlated with higher cell number in the pre-anthesis ovary. This was probably due to the acceleration of the flower growth rate since other flower developmental parameters (schedule and time-course) remained otherwise unaffected. Using RT-PCR, it was shown that the transcript levels of CYCB2;1 (cyclin) and CDKB2;1 (cyclin-dependent kinase), two mitosis-specific genes, strongly increased early in developing flower buds. Remarkably, the transcript abundance of CYCD3;1, a D-type cyclin potentially involved in cell cycle regulation in response to mitogenic signals, also increased by more than 5-fold at very early stages of L1 flower development. By contrast, transcripts from fw2.2, a putative negative regulator of cell division in tomato fruit, strongly decreased in developing flower bud, as confirmed by in situ hybridization studies. Taken together, these results suggest that changes in carbohydrate partitioning could control fruit size through the regulation of cell proliferation-related genes at very early stages of flower development.