Arginine metabolism governs microcycle conidiation by changing nitric oxide content in Metarhizium acridum
Arginine metabolism governs microcycle conidiation by changing nitric oxide content in Metarhizium acridum
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DOI：
10.1007/s00253-022-12355-6
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发表时间：
2023-01-14
影响因子：
5
通讯作者：
Xia, Yuxian
中科院分区：
文献类型：
--
作者：
Li, Mengfei;Wang, Shuqin;Xia, Yuxian
微循环分生孢子广泛存在于丝状真菌中，在真菌杀虫剂的大规模生产中具有巨大的潜力。L-精氨酸代谢是分生孢子形成、条件生长和毒力所必需的，但其在微循环分生孢子形成中的作用尚未被探索。在这里，一个独特的推定的酶（MaAGA）的特点是在昆虫病原真菌绿僵菌acridum。MaAGA的破坏促进了分生孢子的萌发和耐热性。尽管对真菌生长和毒力影响不大，但在正常培养条件下，在微循环分生孢子培养基（SYA）上孵育60 h后，破坏导致正常的分生孢子。在MaAGA破坏突变体（三角洲MaAGA），细胞内精氨酸积累急剧增加。补充的直接代谢产物的酶，即鸟氨酸和/或尿素，不能恢复破坏突变体的SYA上的微循环分生孢子。有趣的是，一氧化氮合酶（NOS）活性和一氧化氮（NO）水平的三角洲MaAGA株显着下降，在60小时的老SYA文化。最后，添加N-ω-硝基-L-精氨酸，一种NOS的抑制剂，到SYA转换的野生型菌株的微循环分生孢子到正常的分生孢子。相比之下，向SYA中添加NO供体硝普钠可以恢复突变体的微循环孢子化。结果表明，精氨酸代谢通过改变NO含量来控制微循环产孢。
Microcycle conidiation commonly exists in filamentous fungi and has great potential for mass production of mycoinsecticides. L-Arginine metabolism is essential for conidiation and conditional growth and virulence, but its role in microcycle conidiation has not been explored. Here, a unique putative arginase (MaAGA) was characterized in the entomopathogenic fungus Metarhizium acridum. Conidial germination and thermotolerance were facilitated by the disruption of MaAGA. Despite little impact on fungal growth and virulence, the disruption resulted in normal conidiation after a 60-h incubation on microcycle conidiation medium (SYA) under normal culture conditions. In the MaAGA-disruption mutant (Delta MaAGA), intracellular arginine accumulation was sharply increased. Replenishment of the direct metabolites of arginase, namely ornithine and/or urea, was unable to restore the disruption mutant's microcycle conidiation on SYA. Interestingly, nitric oxide synthase (NOS) activity and nitric oxide (NO) levels of the Delta MaAGA strain were markedly decreased in the 60-h-old SYA cultures. Finally, adding N-omega-nitro-L-arginine, an inhibitor of NOS, into the SYA converted the microcycle conidiation of the wild-type strain to normal conidiation. In contrast, adding sodium nitroprusside, an NO donor, into the SYA recovered the mutant's microcycle conidiation. The results indicate that arginine metabolism controls microcycle conidiation by changing the content of NO.