Furanocoumarin phytoalexins, trichothecene toxins, and infection of Pastinaca sativa by Fusarium sporotrichioides
Furanocoumarin phytoalexins, trichothecene toxins, and infection of Pastinaca sativa by Fusarium sporotrichioides
复制标题
呋喃香豆素植物抗毒素、单端孢菌素毒素和镰刀菌对 Pastinaca sativa 的感染
DOI：
10.1094/phyto-79-170
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发表时间：
1989
期刊：
影响因子：
3.2
通讯作者：
M. Beremand
中科院分区：
文献类型：
--
作者：
A. E. Desjardins;G. Spencer;R. Plattner;M. Beremand
许多植物致病性镰刀菌产生毛霉烯，这是真核生物中有效的植物毒素和蛋白质合成抑制剂。在这项研究中，我们发现一株产毛霉烯的野生型孢子毛霉菌株NRRL 3299对欧洲防风草（Pastinaca sativa）根系具有致病性，并在植物中产生T-2毒素。感染这种菌株的防风根也积累了大量的真菌毒性呋喃香豆素，主要是黄毒素和当归素。对侵染根的连续切片分析表明，呋喃香豆素浓度在侵染边界处急剧下降，明显不足以完全阻断真菌生长或毛霉素的产生。研究人员利用先前分离的三个互补的NRRL 3299突变体，在T-2毒素生物合成的不同步骤中被阻断，来研究毛霉烯在发病机制中的作用。当这些突变体成对生长在一起并且每个突变体积累不同的最终产物时，T-2毒素的产生就会恢复。在这项研究中，这些突变体感染防风草的能力与它们产生某些毛霉烯的能力有关。因此，积累了4,15-二乙酰氧基旋甲醇的突变体，一种几乎与T-2毒素一样毒性的毛霉烯，与野生型亲本一样具有致病性。相反，积累毒性较低的calonectrin类似物的突变体和积累无毒的trichodiene前体的突变体都不是致病性的。此外，后两种突变体在防风根上同时接种会导致感染。
Many plant pathogenic fusaria produce trichothecenes, which are potent phytotoxins and inhibitors of protein synthesis in eukaryotes. In this study we show that a wild-type, trichothecene-producing strain of F. sporotrichioides, NRRL 3299, is pathogenic on Pastinaca sativa (parsnip) roots and produces T-2 toxin in planta. Parsnip roots infected with this strain also accumulate high levels of fungitoxic furanocoumarins, mainly xanthotoxin and angelicin. Analysis of serial sections of infected roots showed that furanocoumarin concentrations decease sharply at the infection boundary to levels apparently insufficient to completely block fungal growth or trichothecene production. The involvement of trichothecenes in pathogenesis was investigated by using three presiously isolated, complementary mutants of NRRL 3299, blocked at different steps in T-2 toxin biosynthesis. T-2 toxin production is restored when these mutants are grown together pairwise and each mutant accumulates different end products. In this study the ability of these mutants to infect parsnips correlates with their ability to produce certain trichothecenes. Thus, the mutant that accumulates 4,15-diacetoxyscirpenol, a trichothecene nearly as toxic as T-2 toxin, is as pathogenic as the wild-type parent. In contrast, neither the mutant that accumulates the less toxic calonectrin analogues nor the mutant that accumulates the nontoxic trichothecene precursor, trichodiene, is pathogenic. Furthermore, coinocul ation of these latter two mutants on parsnip roots results in infection.