Abstract：
During the last decade, knowledge about BBX proteins has greatly increased. Genome-wide studies identified the BBX gene family in several ornamental, industry, and food crops; however, reports regarding the role of these genes as regulators of agronomically important traits are scarce. Here, by phenotyping a knockout mutant, we performed a comprehensive functional characterization of the tomato locus Solyc12g089240, hereafter called SlBBX20. The data revealed the encoded protein as a positive regulator of light signaling affecting several physiological processes during the life span of plants. Through inhibition of PHYTOCHROME INTERACTING FACTOR 4 (SlPIF4)-auxin crosstalk, SlBBX20 regulates photomorphogenesis. Later in development, it controls the balance between cell division and expansion to guarantee correct vegetative and reproductive development. In fruits, SlBBX20 is transcriptionally induced by the master transcription factor RIPENING INHIBITOR (SlRIN) and, together with ELONGATED HYPOCOTYL 5 (SlHY5), up-regulates flavonoid biosynthetic genes. Finally, SlBBX20 promotes the accumulation of steroidal glycoalkaloids and attenuates Botrytis cinerea infection. This work clearly demonstrates that BBX proteins are multilayer regulators of plant physiology because they affect not only multiple processes during plant development but they also regulate other genes at the transcriptional and post-translational levels.
摘要：
在过去的十年里，关于BBX蛋白的知识突然增加。全基因组研究确定了BBX基因家族在几个观赏植物中，工业和粮食作物；然而，关于这些基因作为农艺学重要性状调节因子的报道很少。这里,通过基因敲除突变体的表型，我们对番茄基因座Solyc12g089240进行了全面的功能表征，以下称为SlBBX20。数据显示，编码的蛋白质是光信号传导的正调节剂，影响植物寿命期间的几个生理过程。通过抑制植物色素相互作用因子4（SlPIF4）-生长素串扰，SlBBX20调节光形态发生。稍后，它控制细胞分裂和扩增之间的平衡，以保证正确的营养和生殖发育。在水果中，SlBBX20由主转录因子RIPENING抑制剂(SlRIN)转录诱导，与延长的下叶5（SlHY5）一起，上调类黄酮生物合成基因。最后,SlBBX20促进类固醇生物碱的积累并减弱灰葡萄孢菌感染。这项工作清楚地表明，BBX蛋白是植物生理学的多层调节剂，不仅因为它们影响植物发育的多个过程，而且还在转录和翻译后水平上调节其他基因。
