Bursicon mediates antimicrobial peptide gene expression to enhance crowded larval prophylactic immunity in the oriental armyworm, Mythimna separata
Bursicon mediates antimicrobial peptide gene expression to enhance crowded larval prophylactic immunity in the oriental armyworm, Mythimna separata
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Bursicon 介导抗菌肽基因表达，增强东方粘虫 Mythimna separata 拥挤幼虫的预防性免疫力
DOI：
10.1016/j.dci.2020.103896
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发表时间：
2021-02-01
影响因子：
2.9
通讯作者：
Luo, Lizhi
中科院分区：
文献类型：
--
作者：
Kong, Hailong;Jing, Wanghui;Luo, Lizhi
据报道，高种群密度改变了昆虫的预防性免疫力。Bursicon在新出现的成年人的预防性免疫中起关键作用。本论文对粘虫（Mythimna separata）幼虫囊体蛋白α和β亚基的全长cDNA进行了鉴定。Msburs α和Msburs β的cDNA分别含有编码145和139个氨基酸残基的蛋白质的开放阅读框（ORF）。多重序列比对和系统发育分析表明，Msbursicons（Msburs alpha和Msburs beta）与其他鳞翅目昆虫中的bursicons是直系同源的。Msbursicons在所有发育状态下表达，在卵、蛹和成虫阶段具有较高的相对表达。相对于其他测试组织，Msbursicon（Msburs α和Msburs β）在腹神经索和脑中高度表达。在整个4龄和5龄阶段，高密度处理（10头/罐）的幼虫比低密度处理（1头/罐）的幼虫的Msbursicon表达量显著增加。抗菌肽（AMP）基因天蚕素C和防御素在试验阶段的表达趋势一致，并延迟与囊体表达的增加。通过在接受高密度处理的幼虫中注射dsRNA来沉默Msburs α（或Msburs β）表达显著降低了天蚕素C和防御素基因的表达水平。重组Msbursicon同源二聚体显着诱导天蚕素C和防御素基因的表达。苏云金白僵菌感染的Msburs alpha（或Msburs beta或Mscecropin C或Msdefensin）敲除幼虫的存活率显著降低。我们的研究结果提供了第一个见解幼虫密度如何介导AMP基因的表达，随后影响高密度条件下的昆虫的预防性免疫。
It has been reported that a high population density alters insect prophylactic immunity. Bursicon plays a key role in the prophylactic immunity of newly emerged adults. In this paper, full-length cDNAs encoding the alpha and beta subunits of bursicon in Mythimna separata larvae (Msburs alpha and Msburs beta) were identified. The cDNAs of Msburs alpha and Msburs beta contain open reading frames (ORFs) encoding 145- and 139-amino acid residue proteins, respectively. Multiple alignment sequences and phylogenetic analysis indicated that Msbursicons (Msburs alpha and Msburs beta) are orthologous to bursicons in other lepidopterans. The Msbursicons were expressed throughout all developmental states with higher relative expression during the egg, pupae, and adult stages. Msbursicons (Msburs alpha and Msburs beta) were highly expressed in the ventral nerve cord and brain relative to other tested tissues. Msbursicon expression of larvae subject to high-density treatment (10 larvae per jar) was significantly increased compared with that of the larvae subject to low-density treatment (1 larva per jar) in the whole fourth and fifth instar stages. The trend in the expression of the antimicrobial peptide (AMP) genes cecropin C and defensin in the test stage was accorded and delayed with increased expression of bursicons. Silencing Msburs alpha (or Msburs beta) expression by dsRNA injection in larvae subject to high-density treatment significantly decreased the expression levels of the cecropin C and defensin genes. Recombinant Msbursicon homodimers significantly induced the expression of the cecropin C and defensin genes. There was a notable decrease in the survival rate of the Msburs alpha (or Msburs beta or Mscecropin C or Msdefensin) knockdown larvae infected by Beauveria thuringiensis. Our findings provide the first insights into how larval density mediates AMP gene expression, which subsequently affects the prophylactic immunity of insects under high-density conditions.