Department of Agricultural Biotechnology, Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea.
FEMS Microbiol Lett. 2010 Jan;302(2):197-202. doi: 10.1111/j.1574-6968.2009.01854.x. Epub 2009 Nov 16.
Carotenoids are a structurally diverse class of terpenoid pigments that are synthesized by many microorganisms and plants. In this study, we identified five putative carotenoid biosynthetic genes from the ascomycete Gibberella zeae (GzCarB, GzCarO, GzCarRA, GzCarT, and GzCarX). HPLC showed that the fungus produces two carotenoids: neurosporaxanthin and torulene. We deleted the five genes individually to determine their functions. GzCarB, GzCarRA, and GzCarT were required for neurosporaxanthin biosynthesis, but the deletion of GzCarX or GzCarO (DeltagzcarX or DeltagzcarO) failed to alter the production of neurosporaxanthin or torulene. DeltagzcarRA and DeltagzcarB did not produce neurosporaxanthin or torulene. DeltagzcarB led to the accumulation of phytoene, which is an intermediate in carotenoid biosynthesis, but DeltagzcarRA did not. DeltagzcarT produced torulene but not neurosporaxanthin. Based on these functional studies and similarities to carotenoid biosynthesis genes in other fungi, we deduced the functions of the three genes and propose the carotenoid biosynthetic pathway of G. zeae.
类胡萝卜素是一类结构多样的萜烯类色素，许多微生物和植物都能合成。在这项研究中，我们从子囊菌禾谷镰刀菌（GzCarB、GzCarO、GzCarRA、GzCarT 和 GzCarX）中鉴定出五个假定的类胡萝卜素生物合成基因。HPLC 显示该真菌产生两种类胡萝卜素：神经鞘氨醇和 torulene。我们分别删除了这五个基因，以确定它们的功能。GzCarB、GzCarRA 和 GzCarT 是神经鞘氨醇生物合成所必需的，但删除 GzCarX 或 GzCarO（DeltagzcarX 或 DeltagzcarO）并不能改变神经鞘氨醇或 torulene 的产生。DeltagzcarRA 和 DeltagzcarB 不能产生神经鞘氨醇或 torulene。DeltagzcarB 导致了类胡萝卜素生物合成中间产物phytoene 的积累，但 DeltagzcarRA 没有。DeltagzcarT 产生了 torulene 但不是神经鞘氨醇。基于这些功能研究以及与其他真菌中类胡萝卜素生物合成基因的相似性，我们推断了这三个基因的功能，并提出了 G. zeae 的类胡萝卜素生物合成途径。
