The formation of propagules is the critical stage for transmission of the pathogenic fungus Stemphylium eturmiunum. However, how the development of these propagules is regulated remains to be fully understood. Here, we show that nitric oxide (NO) is necessary for reproduction in S. eturmiunum.Application of NO scavenger carboxy-CPTIO (cPTIO) or soluble guanylate cyclase (sGC) inhibitor NS-2028 abolishes propagules formation, which was increased by a supplement of sodium nitroprusside (SNP). SNP supplement also triggered increased biosynthesis of melanin, which can be inhibited upon the addition of arbutin or tricyclazole, the specific inhibitors for DOPA and DHN synthetic pathway, respectively. Intriguingly, enhanced melanin biosynthesis corelates with an increased propagules formation; The SNP-induced increment propagules formation can be also compromised upon the supplement of cPTIO or NS-2028. RT-PCR analysis showed that SNP promoted transcription of brlA, abA and wetA at 0.2 mmol/L, but inhibited at 2 mmol/L. In contrast, SNP increased transcription of mat1, and mat2, and the synthetic genes for DHN and DOPA melanins at 2 mmol/L. However, the increased transcription of these genes is down-regulated upon the supplement of cPTIO or NS-2028. Thus, NO regulates reproduction and melanin synthesis in S. eturmiunum possibly through the NO-sGC-GMP signaling pathway.

繁殖体的形成是病原真菌Stemphylium eturmiunum传播的关键阶段 。然而，如何调节这些繁殖体的发育仍有待充分了解。在这里，我们表明一氧化氮 (NO) 是S. eturmiunum繁殖所必需的 。NO 清除剂羧基-CPTIO (cPTIO) 或可溶性鸟苷酸环化酶 (sGC) 抑制剂 NS-2028 的应用消除了繁殖体的形成，这通过补充硝普钠 (SNP) 而增加。SNP 补充剂还引发了黑色素生物合成的增加，这可以通过添加熊果苷或三环唑（分别为 DOPA 和 DHN 合成途径的特异性抑制剂）而受到抑制。有趣的是，增强的黑色素生物合成与增加的繁殖体形成相关；在补充 cPTIO 或 NS-2028 后，SNP 诱导的增量繁殖体形成也会受到影响。RT-PCR分析表明SNP促进了brlA、  abA和wetA的转录 在 0.2 mmol/L 时，但在 2 mmol/L 时被抑制。相比之下，SNP在 2 mmol/L 时增加了mat 1 和mat 2 的转录 ，以及 DHN 和 DOPA 黑色素的合成基因。然而，在补充 cPTIO 或 NS-2028 后，这些基因的转录增加被下调。因此，NO可能通过 NO-sGC-GMP 信号通路调节S. eturmiunum 中的繁殖和黑色素合成 。