A Cytokinin-Activating Enzyme Promotes Tuber Formation in Tomato
A Cytokinin-Activating Enzyme Promotes Tuber Formation in Tomato
复制标题
DOI：
10.1016/j.cub.2013.04.061
复制
发表时间：
2013-06-17
期刊：
影响因子：
9.2
通讯作者：
Lifschitz, Eliezer
中科院分区：
文献类型：
--
作者：
Eviatar-Ribak, Tamar;Shalit-Kaneh, Akiva;Lifschitz, Eliezer
背景：块茎形式的专用储存器官是进化上的新事物，它们具有共同的功能，但起源于不同物种的不同器官。马铃薯（Solanum tuberosum）的块茎是由特化的基部侧生幼枝（称为匍匐茎）膨大的尖端产生的。番茄的侧芽，茄，马铃薯的兄弟种，只形成规则的芽。马铃薯的块茎形成限制在基部幼枝腋生分生组织，而在番茄的分生组织中完全抑制块茎形成的进化机制目前还不清楚。结果：异位表达细胞分裂素（CK）生物合成基因LONELY GUY (LOG 1)，使离体番茄幼芽产生“新生”空中小芽（TMTs）具有潜力。TMTs在形态、发育和代谢方面与马铃薯块茎同源，并显示出独特的转录组和改变的激素信号网络。新的激素平衡刺激休眠腋窝分生组织的异位分支和顶端优势的丧失，而不破坏极性生长素运输，并消除了对特定分支基因的需要。miR156是幼嫩的主要调控因子，在LOG1信号的引导下，野生型马铃薯和番茄的腋芽远端都有形成结节的潜力。结论：TLOG1的普遍激活揭示了番茄腋窝分生组织中发育抑制的结节形成潜能。其他植物的其他分生组织也可能携带隐藏的、被抑制的器官发生潜能。通过单个基因的活动释放这种潜力，代表了进化新事物形成的一个主要例子，并表明ck可能作为植物储存器官形成的普遍调节剂起作用。
Background: Dedicated storage organs in the form of tubers are evolutionary novelties that share a common function but originate in diverse species from different organs. Tubers in potato, Solanum tuberosum, are derived from the swollen tips of specialized basal lateral juvenile shoots, called stolons. Lateral buds of tomato, Solanum lycopersicum, a potato sibling species, only form regular shoots. The evo-devo mechanisms restricting tuber formation to basal juvenile axillary meristems of potato while completely inhibiting it in tomato meristems are not currently understood.Results: Ectopic expression of tomato LONELY GUY (LOG 1), a cytokinin (CK) biosynthesis gene, imparts potential to the outgrowing juvenile tomato buds to generate, de novo, aerial minitubers (TMTs). TMTs are morphologically, developmentally, and metabolically homologous to aerial potato tubers and display a unique transcriptome with altered hormonal signaling networks. The new hormonal balance stimulates ectopic branching of dormant axillary meristems and loss of apical dominance without disruption of polar auxin transport and obviates the need for specific branching genes. miR156, a master regulator of juvenility, extends tuber-forming potential to distal axillary buds in both wild-type potato and tomato primed by LOG1 signaling.Conclusions: Ubiquitous activation of TLOG1 uncovered a developmentally suppressed tuber-forming potential within tomato axillary meristems. Other meristems in other plants may also carry hidden, suppressed organogenesis potentials. The unlocking of this potential by the activity of a single gene represents a prime example of an evolutionary novelty in the making and suggests that CKs may function as universal regulators of storage-organ formation in plants.