CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Menglun, Yunnan 666303, China; University of Chinese Academy of Sciences, Beijing 100049, China.
CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Innovative Academy of Seed Design, Chinese Academy of Sciences, Menglun, Yunnan 666303, China.
Plant Sci. 2024 Jul;344:112100. doi: 10.1016/j.plantsci.2024.112100. Epub 2024 Apr 26.
Jatropha curcas (J. curcas) is a perennial oil-seed plant with vigorous vegetative growth but relatively poor reproductive growth and low seed yield. Gibberellins (GAs) promotes flowering in most annual plants but inhibits flowering in many woody plants, including J. curcas. However, the underlying mechanisms of GA inhibits flowering in perennial woody plants remain unclear. Here, we found that overexpression of the GA biosynthesis gene JcGA20ox1 inhibits flowering in J. curcas and in J. curcas × J. integerrima hybrids. Consistent with this finding, overexpression of the GA catabolic gene JcGA2ox6 promotes flowering in J. curcas. qRTPCR revealed that inhibits floral transition by overexpressing JcGA20ox1 resulted from a decrease in the expression of JcFT and other flowering-related genes, which was restored by overexpressing JcFT in J. curcas. Overexpression of JcGA20ox1 or JcGA2ox6 reduced seed yield, but overexpression of JcFT significantly increased seed yield. Furthermore, hybridization experiments showed that the reduction in seed yield caused by overexpression of JcGA20ox1 or JcGA2ox6 was partially restored by the overexpression of JcFT. In addition, JcGA20ox1, JcGA2ox6 and JcFT were also found to be involved in the regulation of seed oil content and endosperm development. In conclusion, our study revealed that the inhibitory effect of GA on flowering is mediated through JcFT and demonstrated the effects of JcGA20ox1, JcGA2ox6 and JcFT on agronomic traits in J. curcas. This study also indicates the potential value of GA metabolism genes and JcFT in the breeding of new varieties of woody oil-seed plants.
麻疯树（Jatropha curcas）是一种多年生油料植物，具有旺盛的营养生长，但生殖生长较差，种子产量低。赤霉素（GAs）促进大多数一年生植物开花，但抑制许多木本植物开花，包括麻疯树。然而，GA 抑制多年生木本植物开花的潜在机制尚不清楚。在这里，我们发现 GA 生物合成基因 JcGA20ox1 的过表达抑制了麻疯树及其杂种 J. curcas × J. integerrima 的开花。与这一发现一致的是，GA 分解代谢基因 JcGA2ox6 的过表达促进了麻疯树的开花。qRT-PCR 显示，通过过表达 JcGA20ox1 抑制花转变是由于 JcFT 和其他开花相关基因的表达降低，而在麻疯树中过表达 JcFT 则恢复了这些基因的表达。过表达 JcGA20ox1 或 JcGA2ox6 降低了种子产量，但过表达 JcFT 显著增加了种子产量。此外，杂交实验表明，过表达 JcGA20ox1 或 JcGA2ox6 导致的种子产量降低，部分通过过表达 JcFT 得到了恢复。此外，还发现 JcGA20ox1、JcGA2ox6 和 JcFT 也参与了种子含油率和胚乳发育的调节。总之，本研究揭示了 GA 对开花的抑制作用是通过 JcFT 介导的，并证明了 JcGA20ox1、JcGA2ox6 和 JcFT 对麻疯树农艺性状的影响。本研究还表明，GA 代谢基因和 JcFT 在木本油料植物新品种培育中具有潜在价值。
