Differential spatio-temporal expression of carotenoid cleavage dioxygenases regulates apocarotenoid fluxes during AM symbiosis.
Differential spatio-temporal expression of carotenoid cleavage dioxygenases regulates apocarotenoid fluxes during AM symbiosis.
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DOI：
10.1016/j.plantsci.2014.10.010
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发表时间：
2015
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通讯作者：
J. A. López-Ráez;I. Fernández;Juan M. García;Estefanía Berrio;P. Bonfante;M. Walter;M. Pozo
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作者：
J. A. López-Ráez;I. Fernández;Juan M. García;Estefanía Berrio;P. Bonfante;M. Walter;M. Pozo
类伪胡萝卜素是一类在自然界中起重要作用的化合物。近年来，这些化合物在丛枝菌根（AM）共生中起着突出的作用。它们是通过类胡萝卜素裂解双加氧酶(CCD)酶家族的作用从类胡萝卜素中衍生出来的。本研究以番茄为模型，研究了AM共生建立和功能过程中CCD基因的时空表达规律。此外，还分析了类伪胡萝卜素内酯（SLs）、C13α-离子醇和C14菌根素（C13/C14）衍生物的含量。结果表明，在相互作用的早期阶段，AM真菌的存在促进了SL的增加，这与SL生物合成基因eslccd7的诱导有关。在后期，在丛枝细胞中诱导slccd7和slccd1的表达促进了C13/ c14类伪胡萝卜素衍生物的产生。我们在这里表明，AM共生过程中类伪胡萝卜素的生物合成在基因表达水平上受到整个过程的精细调控，而CCD7在这一调控中起关键作用。一旦共生关系建立，类伪胡萝卜素通量将转向C13/ c14衍生物的生产，从而减少SL的生物合成，维持功能性共生关系。
Apocarotenoids are a class of compounds that play important roles in nature. In recent years, a prominent role for these compounds in arbuscular mycorrhizal (AM) symbiosis has been shown. They are derived from carotenoids by the action of the carotenoid cleavage dioxygenase (CCD) enzyme family. In the present study, using tomato as a model, the spatio-temporal expression pattern of the CCD genes during AM symbiosis establishment and functioning was investigated. In addition, the levels of the apocarotenoids strigolactones (SLs), C13α-ionol and C14mycorradicin (C13/C14) derivatives were analyzed. The results suggest an increase in SLs promoted by the presence of the AM fungus at the early stages of the interaction, which correlated with an induction of the SL biosynthesis geneSlCCD7. At later stages, induction ofSlCCD7andSlCCD1expression in arbusculated cells promoted the production of C13/C14apocarotenoid derivatives. We show here that the biosynthesis of apocarotenoids during AM symbiosis is finely regulated throughout the entire process at the gene expression level, and that CCD7 constitutes a key player in this regulation. Once the symbiosis is established, apocarotenoid flux would be turned towards the production of C13/C14derivatives, thus reducing SL biosynthesis and maintaining a functional symbiosis.