An arabinose-induced enhancement of asexual reproduction and concomitant changes in metabolic state in the filamentous fungus Bipolaris maydis
An arabinose-induced enhancement of asexual reproduction and concomitant changes in metabolic state in the filamentous fungus Bipolaris maydis
复制标题
阿拉伯糖诱导的丝状真菌玉米双极菌无性繁殖的增强和代谢状态的伴随变化
DOI：
10.1099/mic.0.001009
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发表时间：
2021
期刊：
影响因子：
1.5
通讯作者：
Tanaka C.
中科院分区：
文献类型：
--
作者：
Yoshida H.; Tanaka C.
L-阿拉伯糖是植物细胞壁多糖的主要成分戊糖，已被认为是真菌不太优选的碳源，但它是一种潜在的信号分子，可以在真菌细胞中引起独特的全基因组转录变化。在这里，我们探讨了这种独特的戊糖影响植物病原真菌双极性真菌 HITO7711 形态特征的可能性。当在不同糖条件下在平板培养基上生长时，仅使用l-阿拉伯糖的培养物的菌丝干重与不使用糖的培养物一样低，这表明l-阿拉伯糖对营养生长没有显着贡献。然而，在l-阿拉伯糖上的分生孢子形成强度与ond-葡萄糖和ond-木糖相当甚至更高，而在无糖条件下分生孢子的形成较差。为了探索l-阿拉伯糖被动生长和主动分生孢子的生理基础，我们接下来研究了真菌对这些糖条件的细胞反应。与碳水化合物代谢相关的基因的转录分析表明，l-阿拉伯糖通过己糖单磷酸分流（HMP 分流）刺激碳水化合物的利用，这是一种与糖酵解平行的分解代谢途径，参与还原剂 NADPH（烟酰胺腺嘌呤二核苷酸磷酸的还原形式）的生成。然后，HMP 分流因破坏相关基因 BmZwf1 而受损，该基因编码该真菌中的葡萄糖-6-磷酸脱氢酶。与野生型相比，所得的仅1-阿拉伯糖突变体显示分生孢子形成显着减少，但相反增加了菌丝干重。我们的研究表明，l-阿拉伯糖可以增强 B 中无性繁殖的资源分配。 maydisHITO7711 以营养生长为代价，并表明这是由 HMP 分流的伴随刺激介导的。
l-Arabinose, a major constituent pentose of plant cell-wall polysaccharides, has been suggested to be a less preferred carbon source for fungi but to be a potential signalling molecule that can cause distinct genome-wide transcriptional changes in fungal cells. Here, we explore the possibility that this unique pentose influences the morphological characteristics of the phytopathogenic fungusBipolaris maydisstrain HITO7711. When grown on plate media under different sugar conditions, the mycelial dry weight of cultures onl-arabinose was as low as that with no sugar, suggesting thatl-arabinose does not substantially contribute to vegetative growth. However, the intensity of conidiation onl-arabinose was comparable to or even higher than that ond-glucose and ond-xylose, in contrast to the poor conidiation under the no-sugar condition. To explore the physiological basis of the passive growth and active conidiation onl-arabinose, we next investigated cellular responses of the fungus to these sugar conditions. Transcriptional analysis of genes related to carbohydrate metabolism showed thatl-arabinose stimulates carbohydrate utilization through the hexose monophosphate shunt (HMP shunt), a catabolic pathway parallel to glycolysis and which participates in the generation of the reducing agent NADPH (the reduced form of nicotinamide adenine dinucleotide phosphate). Then, the HMP shunt was impaired by disrupting the related geneBmZwf1, which encodes glucose-6-phosphate dehydrogenase in this fungus. The resulting mutants onl-arabinose showed remarkably decreased conidiation, but a conversely increased mycelial dry weight compared with the wild-type. Our study demonstrates thatl-arabinose acts to enhance resource allocation to asexual reproduction inB. maydisHITO7711 at the cost of vegetative growth, and suggests that this is mediated by the concomitant stimulation of the HMP shunt.