种子大小是连接植物有性繁殖和随后成苗的关键农艺性状，并受双受精后胚乳增殖后胚乳细胞化时间的影响。到目前为止，控制胚乳细胞化时间的分子开关在很大程度上还不清楚。在这里，我们报道了拟南芥TERMINAL FLOWER1 (TFL1)是在合点胚乳中产生的一种移动调节因子，通过稳定ABSCISIC ACID INSENSITIVE 5（ABI5）来调节合胞外周胚乳适时的细胞化和种子大小。
我们进一步证明了Ras相关的核GTPases与TFL1相互作用并调节其运输到合胞外周胚乳。
我们的研究结果表明，TFL1是调节胚乳细胞化和种子大小的重要分子开关。在靠近母体维管组织的合点胚乳中产生可移动的TFL1，可能为控制母株种子发育提供一种迄今未知的手段。
Seed size is a pivotal agronomic trait that links plant sexual reproduction and subsequent seedling establishment, and is affected by the timing of endosperm cellularization following endosperm proliferation after double fertilization. The molecular switch that controls the timing of endosperm cellularization has so far been largely unclear. Here, we report that the Arabidopsis TERMINAL FLOWER1 (TFL1) is a mobile regulator generated in the chalazal endosperm, and moves to the syncytial peripheral endosperm to mediate timely endosperm cellularization and seed size through stabilizing ABSCISIC ACID INSENSITIVE 5. We further show that Ras-related nuclear GTPases interact with TFL1 and regulate its trafficking to the syncytial peripheral endosperm. Our findings reveal TFL1 as an essential molecular switch for regulating endosperm cellularization and seed size. Generation of mobile TFL1 in the chalazal endosperm, which is close to maternal vascular tissues, could provide a hitherto-unknown means to control seed development by mother plants.
https://www.nature.com/articles/s41477-020-0749-5
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