Identification and Phylogenetic Analysis of Basic Helix-Loop-Helix Genes in the Diamondback Moth

Abstract

Basic helix-loop-helix (bHLH) transcription factors play essential roles in regulating eukaryotic developmental and physiological processes such as neuron generation, myocyte formation, intestinal tissue development, and response to environmental stress. In this study, the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), genome was found to encode 52 bHLH genes. All 52 P. xylostella bHLH (PxbHLH) genes were classified into correspondent bHLH families according to their orthology with bHLHs from fruit fly and other insect species. Among these 52 PxbHLH genes, 19 have been annotated consistently with our classification in GenBank database. The remaining 33 PxbHLH genes are either annotated as general bHLH genes or as hypothetical genes. Therefore, our data provide useful information for updating annotations to PxbHLH genes. P. xylostella has four stem cell leukemia (SCL) genes (one of them has three copies), two Dys genes, two copies of MyoR, Mitf, and Sima genes, and three copies of Sage genes. Further studies may be conducted to elucidate functions of these specific bHLH genes in regulating P. xylostella growth and development.

Genome‐wide identification and characterization of basic helix‐loop‐helix transcription factors in Spodoptera litura upon pathogen infection

“…Similar to D. melanogaster and T. castaneum (Moore et al, 2000;Bitra et al, 2009;Zeng et al, 2018), only 1 AP4 gene and 1 ARNT gene were identified in A. mellifera in our study. P. xylostella contains 52 bHLH genes in 38 families, but lacks AP4 and SREBP genes (Zeng et al, 2018). We identified 56 bHLH genes, including 1 AP4, 1 SREBP, 1 Lep, 1 more Clock, 2 more H/E(spl), and 2 instead of 4 SCL genes in P. xylostella, based on the latest genome annotation (Table S2).…”

“…1). Previous studies also showed that the grouping of bHLH domains of P. xylostella does not follow strict criteria (Wang et al ., 2007; Zeng et al ., 2018). SlbHLHs in groups A, B, and D contain only the bHLH domain, except SlTai.…”

“…A. mellifera contains 55 bHLH genes belonging to 38 families, including 2 AP4 and 2 ARNT genes (Wang et al ., 2008; Zeng et al ., 2018). Similar to D. melanogaster and T. castaneum (Moore et al ., 2000; Bitra et al ., 2009; Zeng et al ., 2018), only 1 AP4 gene and 1 ARNT gene were identified in A. mellifera in our study. P. xylostella contains 52 bHLH genes in 38 families, but lacks AP4 and SREBP genes (Zeng et al ., 2018).…”

“…The numbers of bHLH genes in 5 insect species vary from 53 in A. mellifera to 59 in D. melanogaster , and are consistent with a previous study (Zeng et al ., 2018). Amos from the Atonal family of group A and Sidpn from the H/E(spl) family of group E are not present in lepidopteran species.…”

“…Genomes of S. litura (GCF_002706865.1) (Cheng et al ., 2017), Drosophila melanogaster (GCF_000001215.4) (Hoskins et al ., 2015), A. mellifera (GCF_003254395.2) (Wallberg et al ., 2019), Tribolium castaneum (GCF_000002335.3) (Richards et al ., 2008), and P. xylostella (GCF_905116875.1) (Whiteford et al ., 2019) were downloaded from NCBI. Previously reported bHLH proteins in D. melanogaster (Moore et al ., 2000) and P. xylostella (Zeng et al ., 2018) were used to search for bHLH homologs in S. litura using BLASTP, followed by manual improvement. SMART was used to analyze the conserved domains of bHLH proteins (Letunic et al ., 2015).…”