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De novo Genome Assembly of Auanema melissensis, a Trioecious Free-Living Nematode Cover

De novo Genome Assembly of Auanema melissensis, a Trioecious Free-Living Nematode

Open Access
|Feb 2023

Figures & Tables

Figure S1

Diagram of the experimental design to test if the crowding cues experienced by hermaphrodite mothers change the sex ratios of the F1 generation. Dauer larvae were isolated onto five 6 cm plates under each condition (control and crowded) and left to mature into a hermaphrodite. F1 eggs were then collected and placed individually onto non-treated 3.5 cm plates. Egg collection occurred >3 d and hermaphrodite mothers were moved to new plates (of their original condition) each day. Eggs were allowed to develop until adulthood and sexed.
Diagram of the experimental design to test if the crowding cues experienced by hermaphrodite mothers change the sex ratios of the F1 generation. Dauer larvae were isolated onto five 6 cm plates under each condition (control and crowded) and left to mature into a hermaphrodite. F1 eggs were then collected and placed individually onto non-treated 3.5 cm plates. Egg collection occurred >3 d and hermaphrodite mothers were moved to new plates (of their original condition) each day. Eggs were allowed to develop until adulthood and sexed.

Figure S2

Visualization of the contamination present in the four genomic libraries using BlobTools. The libraries were generally free from contaminants except for a few (<2%) proteobacteria most likely corresponding to the nematode food source (E. coli strain OP50-1).
Visualization of the contamination present in the four genomic libraries using BlobTools. The libraries were generally free from contaminants except for a few (<2%) proteobacteria most likely corresponding to the nematode food source (E. coli strain OP50-1).

Figure 1

Pictures of a (A) male, (B) female, and (C) hermaphrodite of Auanema melissensis on day 1 of adulthood (100× magnification). A dauer larva (D), fated to develop as a hermaphrodite, is depicted at a magnification of 112×.
Pictures of a (A) male, (B) female, and (C) hermaphrodite of Auanema melissensis on day 1 of adulthood (100× magnification). A dauer larva (D), fated to develop as a hermaphrodite, is depicted at a magnification of 112×.

Figure 2

Differences between females and hermaphrodites during the first three days of adulthood. (A) Representative example of the size and pigmentation differences between A. melissensis females and hermaphrodites over the first 3 d of adulthood (100× magnification). The scale bar is the same for all images. (B) Hermaphrodites’ body length is longer than that of females during the first three days of adulthood (repeated measures ANOVA F(1, 8) = 26.580, P < 0.05). As the worms aged, they also became longer (repeated measures ANOVA F(2, 16) = 19.151, P < 0.05).
Differences between females and hermaphrodites during the first three days of adulthood. (A) Representative example of the size and pigmentation differences between A. melissensis females and hermaphrodites over the first 3 d of adulthood (100× magnification). The scale bar is the same for all images. (B) Hermaphrodites’ body length is longer than that of females during the first three days of adulthood (repeated measures ANOVA F(1, 8) = 26.580, P < 0.05). As the worms aged, they also became longer (repeated measures ANOVA F(2, 16) = 19.151, P < 0.05).

Figure 3

Male tail characters of A. melissensis. Micrographs (A) and (B) show the spicules. Male tail in ventral (C) and lateral (D) orientation. “ph” = Phasmid, “CO” = cloaca, “gb” = gubernaculum, “vh” = ventral hook. Genital papillae/rays are designated by arrowheads and named r1-r8.
Male tail characters of A. melissensis. Micrographs (A) and (B) show the spicules. Male tail in ventral (C) and lateral (D) orientation. “ph” = Phasmid, “CO” = cloaca, “gb” = gubernaculum, “vh” = ventral hook. Genital papillae/rays are designated by arrowheads and named r1-r8.

Figure S3

Whole body length of males (n = 10), females (n = 10) and hermaphrodites (n = 10).
Whole body length of males (n = 10), females (n = 10) and hermaphrodites (n = 10).

Figure 4

Hermaphrodite production is promoted when A. melissensis hermaphrodite mothers are cultured in the presence of a crowding cue. The boxplots were drawn from the proportion of hermaphrodites (number of hermaphrodites/number of hermaphrodites and females) under each condition for each replicate.
Hermaphrodite production is promoted when A. melissensis hermaphrodite mothers are cultured in the presence of a crowding cue. The boxplots were drawn from the proportion of hermaphrodites (number of hermaphrodites/number of hermaphrodites and females) under each condition for each replicate.

Figure 5

Phylogenetic position of A. melissensis. Single-copy BUSCO orthologs (2071) were used to build a concatenated alignment, which was subsequently used to construct the phylogenetic tree. The supermatrix alignment was 1,018,758 amino acids in length.
Phylogenetic position of A. melissensis. Single-copy BUSCO orthologs (2071) were used to build a concatenated alignment, which was subsequently used to construct the phylogenetic tree. The supermatrix alignment was 1,018,758 amino acids in length.

Whole body measurements of ten males, females and hermaphrodites_

IDSexual morphLength (μm)
MM1Male408.007
MM2Male417.763
MM3Male459.784
MM4Male416.338
MM5Male448.795
MM6Male440.899
MM7Male461.569
MM8Male446.739
MM9Male431.713
MM10Male440.548
FM1Female823.88
FM2Female762.546
FM3Female761.116
FM4Female853.252
FM5Female945.703
FM6Female918.242
FM7Female894.754
FM8Female912.291
FM9Female741.757
FM11Female926.158
HM1Hermaphrodite1,006.355
HM2Hermaphrodite960.354
HM3Hermaphrodite1,001.369
HM4Hermaphrodite1,024.498
HM5Hermaphrodite856.356
HM6Hermaphrodite1,010.322
HM7Hermaphrodite839.704
HM8Hermaphrodite986.148
HM10Hermaphrodite982.561
HM11Hermaphrodite963.425

Number of F1 males, females and hermaphrodites produced by selfing mothers in the absence (control) and presence (crowding) of a crowding cue_

ReplicateMale (%)Female (%)Hermaphrodite (%)Total
Control 19 (11.7)68 (88.3)0 (0)77
Control 23 (7.7)35 (89.7)1 (2.6)39
Control 31 (7.7)9 (69.2)3 (23.1)13
Control 44 (23.5)13 (76.5)0 (0.0)17
Control 50 (0.0)45 (97.8)1 (2.2)46
Total Control17 (8.9)170 (88.5)5 (2.6)192
Crowding 10 (0.0)15 (88.2)2 (11.8)17
Crowding 20 (0.0)15 (68.2)7 (31.8)22
Crowding 31 (2.2)44 (95.7)1 (2.2)46
Crowding 40 (0.0)27 (56.3)21 (43.8)48
Crowding 50 (0.0)8 (19.5)33 (80.5)41
Total Crowding1 (0.6)109 (62.6)64 (36.8)174

BUSCO scores of the genomes used to construct the phylogeny_

CompleteComplete and single copyComplete and duplicatedFragmentedMissing
A. melissensis (this study, GCA_943334845.1)2,784 (88.9%)2,771 (88.5%)13 (0.4%)45 (1.4%)302 (9.7%)
A. freiburgensis (Talal Al Yazeedi, pers. comm.)2,789 (89.1%)2,756 (88.0%)33 (1.1%)48 (1.5%)294 (9.4%)
A. rhodensis (GCA_947366455)2,812 (89.8%)2,796 (89.3%)16 (0.5%)39 (1.2%)280 (9.0%)
O. tipulae (GCA_013425905.1)2,843 (90.8%)2,786 (89.0%)57 (1.8%)47 (1.5%)241 (7.7%)
C. elegans (GCF_000002985.6)3,113 (99.4%)3,096 (98.9%)17 (0.5%)3 (0.1%)15 (0.5%)
P. pacificus (GCA_000180635.4)2,587 (82.6%)2,537 (81.0%)50 (1.6%)38 (1.2%)506 (16.2%)

Preprocessing of the genomic libraries_

Library (insert size)Number of raw pairsNumber of pairs after trimming (quality and size)*Number of pairs after contamination removal
Pair-end DNA library (200 bp)68,587,06468,109,105 (99.30%)67,271,297
Mate-pair DNA library (3 kb)16,195,0939,920,448 (61.26%)9,766,526
Mate-pair DNA library (5 kb)11,655,4877,484,279 (64.21%)7,372,147
Mate-pair DNA library (8 kb)10,769,1337,125,674 (66.17%)7,017,505

Genomic and transcriptomic raw data used in this study_

Library (insert size)Number of raw pairsGC content (%)Run accession number (experiment acc)
Pair-end DNA library (200 bp)68,587,06437ERR9709439 (ERX9258761)
Mate-pair DNA library (3 kb)16,195,09337ERR9709942 (ERX9259264)
Mate-pair DNA library (5 kb)11,655,48737ERR9710904 (ERX9260226)
Mate-pair DNA library (8 kb)10,769,13337ERR9709954 (ERX9259276)
RNA-seq library of mixed stages22,509,19544ERR9712246 (ERX9261548)

Basic statistics on the genome of A_ melissensis compared to that of C_ elegans_ The nematoda_odb10 database was used for the BUSCO analysis_

A. melissensis PRJEB51845/ GCA_ 943334845.1C. elegans PRJNA13758/ GCF_ 000002985.6
Number of scaffolds7,5116 + MT
Span (Mb)59.7100.3
GC content (%)37.135.4
N50 (bp)404,820 (n = 39)17,493,829
Longest scaffold/ chromosome2,171,61120,924,180
N counts5,769,0060.00
Gaps3,945NA
Repeats4,816,819 bp (8.07%)(21.95%)
BUSCO (v5.2.2) score (on genome)C: 88.9% [S: 88.5%, D: 0.4%], F: 1.4%, M: 9.7%, n: 3,131C: 99.4% [S: 98.9%, D: 0.5%], F: 0.1%, M: 0.5%
No. of protein-coding genes11,04020,184
BUSCO (v5.2.2) score (on the proteome, using nematoda_ odb10, n = 3,131)C: 89.7% [S: 77.2%, D: 12.5%], F: 1.1%, M: 9.2%C: 100.0% [S: 74.8%, D: 25.2%], F: 0.0%, M: 0.0%

Crosses were performed between A_ melissensis and A_ rhodensis or A_ freiburgensis_ The number of crosses performed is denoted by “n_”

Males
A. melissensisA. rhodensisA. freiburgensis
FemalesA. melissensis No offspring (n = 5)No offspring (n = 11)
A. rhodensisNo offspring (n = 5)
A. freiburgensisNo offspring (n = 8)

Putative X scaffolds_ Scaffolds containing at least 3 Nigon X BUSCO genes were considered putative X scaffolds_

ScaffoldsNumber of Nigon X BUSCO genesNumber of BUSCO genes of other Nigons
scaffold120 (CALQYR010007222.1)100
scaffold167 (CALQYR010007273.1)180
scaffold125 (CALQYR010007227.1)50
scaffold146 (CALQYR010007250.1)50
scaffold91 (CALQYR010007503.1)120
scaffold79 (CALQYR010007489.1)70
scaffold72 (CALQYR010007482.1)60
scaffold42 (CALQYR010007449.1)30
scaffold41 (CALQYR010007448.1)30
scaffold190 (CALQYR010007299.1)30
scaffold168 (CALQYR010007274.1)30

Classification of the repeats by Repeat Masker_

CategoryNumber of elements*Length occupied (bp)Percentage of sequence
SINEs (all)307,7570.01
SINEs (ALUs)000.00
SINEs (MIRs)000.00
LINEs (all)7822,8280.04
LINEs (LINE1)000.00
LINEs (LINE2)104,0880.01
LINEs (L3/CR1)145,5070.01
LTR elements (all)1,799727,0031.22
LTR elements (ERVL)000.00
LTR elements (ERVL-MaLRs)000.00
LTR elements (ERV_classI)000.00
LTR elements (ERV_classII)000.00
DNA elements430161,0380.27
DNA elements (hAT-Charlie)000.00
DNA elements (TcMar-Tigger)18070.00
Unclassified6,8502,109,4483.53
Total interspersed repeatsNA3,028,0745.07
Small RNA792186,9730.31
Satellites16746,7550.08
Simple repeats24,6871,082,6941.81
Low complexity8,083464,8280.78
DOI: https://doi.org/10.2478/jofnem-2022-0059 | Journal eISSN: 2640-396X | Journal ISSN: 0022-300X
Language: English
Submitted on: Sep 25, 2022
Published on: Feb 7, 2023
Published by: Society of Nematologists, Inc.
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year

© 2023 Sophie Tandonnet, Maairah Haq, Anisa Turner, Theresa Grana, Panagiota Paganopoulou, Sally Adams, Sandhya Dhawan, Natsumi Kanzaki, Isabelle Nuez, Marie-Anne Félix, André Pires-daSilva, published by Society of Nematologists, Inc.
This work is licensed under the Creative Commons Attribution 4.0 License.