Campylosiphon

Li, Xiaojuan, Qu, Lu, Hu, Guoxiong & Zhang, Dianxiang, 2023, Revision of Campylosiphon (Burmanniaceae), with New Combinations and a New Species Described, Systematic Botany (Basel, Switzerland) 48 (3), pp. 395-409 : 397-399

Plastomes of Two Species in Campylosiphon —Like the plastome of Burmannia disticha L., an autotrophic species ( Ma et al. 2018), both plastomes of Burmannia championii and the proposed new species of Campylosiphon have typical plastome

structure with two inverted regions (IRs) separated by a large single-copy region (LSC) and a small single-copy region ( Fig. 6 ). The plastomes of B. championii and the proposed new Campylosiphon species are reduced in both length and gene contents compared with those of B. disticha having plastome with ca. 150 kbp length and 112 genes ( Ma et al. 2018) and C. congestus plastome with ca. 120 kbp in length ( Lam 2016). Plastomes of the three individuals of B. championii are 85,890 bp, 85,984 bp, and 86,051 bp and contain 88 genes (79 intact genes and nine partial genes), 23 genes of which are located in inverted repeat region. The plastome of the newly found entity is 58,703 bp in length and contains 66 genes including 12 partial genes. IRs of B. championii plastome are ca. 26,690 bp in length, while the IRs of Campylosiphon sp. are reduced to 466 bp.

Phylogenetic Inference —There are five plastid encoding protein genes (infA, rpl14, rps12, rps14, and rps19) present among the four Burmanniaceae genera sampled consisting of Apteria , Burmannia , Campylosiphon , and Gymnosiphon . The phylogenetic trees inferred using both five shared genes only, or all 78 plastid protein-coding genes exhibited that Burmannia s.s. was sister to the other three genera, and the clade consisting of Apteria and Gymnosiphon has extremely long branch lengths ( Fig. 7A, C ). Excluding the species of Apteria and Gymnosiphon , the phylogenetic results strongly supported the proposed new species as part of the group formed by B. championii and C. congestus ( Fig. 7B ) based on coding sequences of 78 plastid protein-coding genes. Both the partial 18S sequences matrix (Supplemental Fig. S3 , Li et al. 2023) and the concatenated matrix of mitochondrial DNA sequences (partial of atp1, matR, and nad1 b-c) (Supplemental Fig. S4 , Li et al. 2023) placed Dictyostega orobanchoides (Hook.) Miers into Campylosiphon , and the partial 18S sequences matrix also placed Burmannia longifolia Becc. into Campylosiphon , both of which were with low bootstrap values, though (Supplemental Fig. S3 ). Phylogenetic analyses based on both the concatenated 13 mitochondrial genes ( Fig. 8A ) and the concatenated matrix of the mitochondrial DNA sequences (partial of atp1, matR and nad1 b-c) and partial 18S sequences indicated that the Burmanniaceae genera sampled were monophyletic, and the phylogenetic relationships of the genera were not resolved ( Fig. 8B ).

Phylogenetic inference based on the mitochondrial nad1 b-c sequence showed that B. championii , B. densiflora , and C. congestus (an individual distinct from the typical C. congestus , were respectively named Campylosiphon congestus 1 and C. congestus 2 in Fig. 9 ) were grouped as the sister clade of the other Campylosiphon species ( Fig. 9 ), and weakly supported that the proposed new species was sister to the clade formed by C. purpurascens and C. congestus (specimen voucher: Jongkind 5463 (WAG), named C. congestus 3 in Fig. 9 ) ( Fig. 9 ).

Figures

FIG. 6. Complete plastome maps of Campylosiphon congestus and Campylosiphon saundersii. Genes outside the circle are transcribed counterclockwise, genes inside the circle are transcribed clockwise, and colors indicate the functions of genes.

FIG. 7. Maximum likelihood phylogenetic trees of Burmanniaceae based on the concatenated matrix including the coding sequences of the plastid genes encoding proteins. A. Phylogenetic tree based on the concatenated matrix of the coding sequences of 78 plastid genes encoding proteins. B. Phylogenetic tree based on the concatenated matrix of the coding sequences of 78 plastid genes encoding proteins excluding Apteria and Gymnosiphon. C. Phylogenetic tree based on the concatenated matrix of five shared plastid genes among Burmanniaceae. Name of taxon in red indicates this taxon is fully mycoheterotrophic.

FIG. 3. Five species of Campylosiphon. A. Campylosiphon congestus, photographed by Dr. Merckx. B. Campylosiphon densiflorus, part of holotype (Barcode: B100165441). C. Campylosiphon purpurascens, photographed by Dr. Merckx. D. Campylosiphon championii, photographed by Xiaojuan Li. E. Campylosiphon saundersii, photographed by Lu Qu.

FIG. 4. Continuous variation of floral morphology among Campylosiphon lineages. A. Campylosiphon purpurascens, partial of holotype (Barcode: B100165441). B. Campylosiphon saundersii, photographed by Qu Lu. C. Campylosiphon congestus, partial of specimen sheet (Barcode: E00044117). D. Campylosiphon congestus, partial of holotype (Barcode: K000366035). E. Campylosiphon sp., partial of herbarium specimen collected from the Western Ghat, India (Barcode: MH00018421). F. Campylosiphon championii, partial of holotype of Burmannia chionantha (Barcode: B100296387). G. Campylosiphon sp., partial of herbarium specimen collected from Java (Barcode: L.1486663). H. Campylosiphon congestus, partial of holotype of Burmannia aptera (Barcode: B100165442). I. Campylosiphon championii, partial of holotype of Burmannia dalzielii (Barcode: BM000058511). J. Campylosiphon densiflorus, part of holotype (Barcode: B100165441). K. Campylosiphon championii, partial of Burmannia tuberosa lectotype (Barcode: FI013466). L. Burmannia micropetala, partial of holotype (Barcode: BM000058513).

FIG. 8. Maximum likelihood phylogenetic trees of Burmanniaceae based on mitochondrial genes and 18S sequences. A. Phylogenetic tree based on the concatenated 13 mitochondrial gene alignments. B. Phylogenetic tree based on the concatenated matrix of 18S and three mitochondrial DNA sequences (atp1, matR, and nad1 b-c). Name of taxon in red indicates this taxon is fully mycoheterotrophic.

FIG. 9. Phylogenetic relationships of Campylosiphon species based on mitochondrial sequence nad1 b-c. Name of taxon in red indicates this taxon is fully mycoheterotrophic.