精胺合成酶MrSPS参与调控罗伯茨绿僵菌的生长发育、抗逆和致病力

Spermine synthase is involved in the regulation of development,stress response and pathogenicity of Metarhizium robertsii

本研究以罗伯茨绿僵菌Metarhizium robertsii为研究对象,针对鉴定出的精胺合成酶基因(MAA_02088,Mrsps),利用农杆菌介导的同源重组方法获得Mrsps敲除株ΔMrsps。与野生型相比,ΔMrsps营养生长和产孢能力下降,对氯化钠和紫外照射耐受性增强。大蜡螟幼虫毒力分析表明,浸渍和注射两种情况下ΔMrsps致病力降低,半致死时间(LT50:6.71和4.75 d)比野生型(LT50:5.17和4.19 d)显著增加。Mrsps敲除后不影响附着胞形成率和蝉翅穿透能力,但会显著下调昆虫血腔定殖相关基因的表达量。这些结果说明精胺合成酶Mr SPS参与调控罗伯茨绿僵菌的生长发育、外界胁迫应答和致病力。

This study aimed at characterizing the function of spermine synthase gene(MAA_02088,Mrsps)by knocking it out with Agrobacterium-mediated homologous recombination in Metarhizium robertsii.Compared to the wild-type,knocking strainΔMrsps showed defects in radial growth and conidial production,and increase in tolerance to ultraviolet irradiation and NaCl.The results of bioassay showed reduction of virulence ofΔMrsps infecting Galleria mellonella under the conditions of topical inoculation and injection,and the LT50s of insect infected byΔMrsps were markedly longer than those of insect infected by the wild-type.Different fungal strains exhibited similar abilities on appressorium formation and cicada wing penetration,but the expression of the genes involved in hemocoel colonization were significantly downregulated after Mrsps deletion.These results indicate that spermine synthase is involved in the regulation of development,stress response and pathogenicity of M.robertsii.