College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences; Jiangsu Key Laboratory for Food and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China.
Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences; Jiangsu Key Laboratory for Food and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Nanjing 210014, China.
Pestic Biochem Physiol. 2024 Sep;204:106090. doi: 10.1016/j.pestbp.2024.106090. Epub 2024 Aug 19.
Chilo suppressalis, a critical rice stem borer pest, poses significant challenges to rice production due to its overlapping generations and irregular developmental duration. These characteristics complicate pest management strategies. According to the dynamic analysis of the overwintering adults of C. suppressalis in fields, it indicates that the phenomenon of irregular development of C. suppressalis exists widely and continuously. This study delves into the potential role of the Broad-Complex (Br-C) gene in the developmental duration of C. suppressalis. Four isoforms of Br-C, named CsBr-C Z1, CsBr-C Z2, CsBr-C Z4, and CsBr-C Z7, were identified. After CsBr-Cs RNAi, the duration of larva development spans extended obviously. And, the average developmental duration of dsCsBr-Cs feeding individuals increased obviously. Meanwhile, the average developmental duration of the dsCsBr-C Z2 feeding group was the longest among all the RNAi groups. After dsCsBr-Cs feeding continuously, individuals pupated at different instars changed obviously: the proportion of individuals pupated at the 5th instar decreased and pupated at the 7th instar or higher increased significantly. Moreover, the pupation rate of dsCsBr-Cs (except dsCsBr-C Z7) were significantly lower than that of dsGFP. The same results were obtained from the mutagenesis in CsBr-C genes mediated by CRISPR/Cas9. The average developmental duration of CsBr-Cs knockout individuals was significantly prolonged. And, the instar of pupation in knockout individuals was also delayed significantly. In conclusion, this work showed that CsBr-Cs played a crucial role in pupal commitment and affected the developmental duration of C. suppressalis significantly.
二化螟是一种严重危害水稻的钻蛀性害虫，其世代重叠和发育历期不规律给害虫的综合防治带来了困难。本研究采用动态分析田间二化螟越冬代成虫的方法，发现二化螟发育不规律的现象广泛而持续存在。本研究探讨了 Broad-Complex（Br-C）基因在二化螟发育历期中的潜在作用。鉴定出了四个 Br-C 基因的异构体，分别命名为 CsBr-C Z1、CsBr-C Z2、CsBr-C Z4 和 CsBr-C Z7。在进行 CsBr-Cs RNAi 后，幼虫的发育时间明显延长。而且，dsCsBr-Cs 喂养个体的平均发育时间明显增加。同时，dsCsBr-C Z2 喂养组的平均发育时间在所有 RNAi 组中最长。在连续喂食 dsCsBr-Cs 后，不同龄期化蛹的个体发生了明显变化：5 龄化蛹的比例明显减少，7 龄或更高龄化蛹的比例显著增加。此外，dsCsBr-Cs（除 dsCsBr-C Z7 外）的化蛹率明显低于 dsGFP。CRISPR/Cas9 介导的 CsBr-C 基因的突变也得到了相同的结果。CsBr-Cs 敲除个体的平均发育时间明显延长，化蛹的龄期也明显延迟。综上所述，本研究表明 CsBr-Cs 在蛹化的决定中起着关键作用，并显著影响二化螟的发育历期。
