A polyketide synthase, BbpksP, contributes to conidial cell wall structure and UV tolerance in Beauveria bassiana.
A polyketide synthase, BbpksP, contributes to conidial cell wall structure and UV tolerance in Beauveria bassiana.
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DOI：
10.1016/j.jip.2019.107280
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发表时间：
2019-11
影响因子：
3.4
通讯作者：
Junyao Wang;Yuge Ma;Yu Liu;S. Tong;Shengan Zhu;D. Jin;Y. Pei;Yanhua Fan
中科院分区：
文献类型：
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作者：
Junyao Wang;Yuge Ma;Yu Liu;S. Tong;Shengan Zhu;D. Jin;Y. Pei;Yanhua Fan
丝状真菌分生孢子色素在真菌生物/非生物胁迫耐受中起着重要作用，通常由聚酮酶或其他色素合成蛋白合成。球孢白僵菌（Beauveria bassiana）是一种重要的昆虫病原真菌，在人工培养基上能产生白色分生孢子，但在其分生孢子色素中未见报道。然而，real-time PCR和启动子报告分析显示了B. bassiana（命名为BbpksP）基因是黑色素合成基因的同源基因，在气生分生孢子中特异表达。我们发现，BbpksP的缺失不会导致分生孢子产量，发芽率或菌落径向生长的变化，但是，缺陷损害分生孢子细胞壁结构。透射电镜观察发现，野生型分生孢子的细胞外膜边缘有一致密的电子层，而Δ BbpksP突变型分生孢子的细胞外膜边缘没有致密的电子层。BbpksP基因的缺失也降低了B.巴西乌头属生物测定表明BbpksP的缺失降低了B.通过局部感染防治大蜡螟。这些数据表明BbpksP的产物有助于B的完整性。细胞壁的变化，进而影响其对UV-B胁迫的耐受性和杀虫活性。
Conidial pigments of filamentous fungi play vital roles in fungal biotic/abiotic stress tolerance and are usually synthesized by polyketide synthases or other pigment synthesis proteins.Beauveria bassiana, an important insect pathogenic fungus used worldwide for pest biocontrol, produces white conidia on artificial media, while no conidial pigment has been observed or reported in it. However, real-time PCR and promoter-report analyses reveal a polyketide gene ofB. bassiana(namedBbpksP), homologous to melanin synthesis genes, is specifically expressed in aerial conidia. We show that deletion ofBbpksPdoes not result in changes in conidial yield, germination rate or colony radial growth; however, the defect impairs conidial cell wall structure. A dense electron layer appears in the outer edge of the cell envelope in wild-type conidia, as observed by TEM, but this dense layer is absent in theΔBbpksPmutant. The lack ofBbpksPgene also reduces the UV-B tolerance ofB. bassianaconidia. Bioassay reveals that deletion ofBbpksPdecreased virulence ofB. bassianaagainstGalleria mellonellalarvae via topical infection. These data indicate that the product(s) ofBbpksPcontributes to the integrity of theB. bassianaconidial cell wall and further affects the tolerance of UV-B stress and insecticidal activity.