School of Life Sciences, University of Science and Technology of China, Hefei 230027, China.
CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Menglun, Mengla 666303, China.
Int J Mol Sci. 2020 Jan 18;21(2):640. doi: 10.3390/ijms21020640.
L. is monoecious with a low female-to-male ratio, which is one of the factors restricting its seed yield. Because the phytohormone cytokinins play an essential role in flower development, particularly pistil development, in this study, we elevated the cytokinin levels in flowers through transgenic expression of a cytokinin biosynthetic gene () from Arabidopsis under the control of a orthologue of () promoter that is predominantly active in flowers. As expected, the levels of six cytokinin species in the inflorescences were elevated, and flower development was modified without any alterations in vegetative growth. In the transgenic plants, the flower number per inflorescence was significantly increased, and most flowers were pistil-predominantly bisexual, i.e., the flowers had a huge pistil surrounded with small stamens. Unfortunately, both the male and the bisexual flowers of transgenic were infertile, which might have resulted from the continuously high expression of the transgene during flower development. However, the number and position of floral organs in the transgenic flowers were well defined, which suggested that the determinacy of the floral meristem was not affected. These results suggest that fine-tuning the endogenous cytokinins can increase the flower number and the female-to-male ratio in .
L 是雌雄同体的，且雌雄比例低，这是限制其种子产量的因素之一。由于植物激素细胞分裂素在花发育中起着至关重要的作用，特别是在雌蕊发育中，因此在这项研究中，我们通过在转基因植物中表达拟南芥的细胞分裂素生物合成基因（），在花中提高细胞分裂素水平，该基因受主要在花中活跃的 （）启动子的控制。正如预期的那样，花序中六种细胞分裂素物质的水平升高，并且在不改变营养生长的情况下修饰花发育。在转基因 植物中，花序上的花数显著增加，大多数花是雌蕊占优势的两性花，即花有一个巨大的雌蕊，周围有小雄蕊。不幸的是，转基因 植物的雄性和两性花都不育，这可能是由于在花发育过程中持续高水平表达转基因。然而，转基因花的花器官的数量和位置定义明确，这表明花分生组织的确定性不受影响。这些结果表明，精细调节内源性细胞分裂素可以增加 中的花数和雌-雄比例。
