Michaelmoelleria (Gesneriaceae), a new lithophilous dwelling genus and species with zigzag corolla tube from southern Vietnam

Michaelmoelleria (Gesneriaceae), a new lithophilous dwelling genus and species with zigzag corolla tube from southern Vietnam
expand article infoFang Wen, Zi-Bing Xin, Long-Fei Fu, Shu Li, Lan-Ying Su, Stephen Maciejewski, Zhang-Jie Huang, Truong Van Do, Yi-Gang Wei

Citation: Wen F, Xin Z-B, Fu L-F, Li S, Su L-Y, Maciejewski S, Huang Z-J, Do TV, Wei Y-G (2020) Michaelmoelleria (Gesneriaceae), a new lithophilous dwelling genus and species with zigzag corolla tube from southern Vietnam. PhytoKeys 146: 89-107.

Abstract
Michaelmoelleria, a new genus from southern Vietnam is described with a single species, M. vietnamensis. The new genus is morphologically most similar to Deinostigma and Tribounia but it differs from the latter two by having four fertile stamens. Nuclear ribosomal internal transcribed spacer (ITS) region and plastid trnL-F intron spacer (trnL-F) DNA sequence data from the new genus and eighty-seven species representing 42 genera within tribe Didymocarpeae are used to resolve its generic placement. The molecular evidence reveals that it is most closely related to Cathayanthe rather than Deinostigma and Tribounia. The chromosome number is counted as 2n = 36 that further clarified its distinction comparing to the related genera within tribe Didymocarpeae. A global conservation assessment is also performed and classifies Michaelmoelleria vietnamensis as Critically Endangered (CR).
Keywords
Cathayanthe, cliff-dwelling, Deinostigma, Didymocarpoideae, flora of Vietnam, IUCN, phylogeny, Tribounia
Morphological observations and specimens examined
A study of the new genus Michaelmoelleria and the only currently known species, M. vietnamensis, from southern Vietnam, was undertaken. All available specimens of Michaelmoelleria are stored in the following herbaria in China and Vietnam: IBK and VNMN (herbarium acronyms according to Index Herbariorum; Thiers 2016, 2019). All morphological characters were studied using a dissecting microscope (SZX16, Olympus, Tokyo, Japan). Characteristics were described using the applicable terminology presented by Wang et al. (1998). The morphological comparison with other species was based on the study of living plants in the field, in cultivation in the VNMN and the GCCC, and herbarium specimens.
Genomic DNA extraction, PCR amplification, and Sequencing
To confirm the placement of this new plant, we performed phylogenetic inference of DNA sequence data obtained from the nuclear ribosomal internal transcribed spacer (ITS) region and the plastid trnL-F intron spacer (trnL-F). Eighty-seven species representing 42 genera as in-group and two species representing one genus as an out-group, including nearly all genera within tribe Didymocarpeae, were sampled. DNA extraction, PCR amplification, and sequencing were performed, following Wei et al. (2013). Sequences obtained from this study and GenBank are listed in the Appendix I.
Phylogenetic analysis
Sequence data were edited and assembled using Lasergene Navigator 7.1 (DNAstar, Madison, Wisconsin, USA). Cleaned sequences were aligned with Geneious R11 (Kearse et al. 2012). Regions of ambiguous alignment and sites with more than 80% missing data were excluded during analyses (Sun et al. 2018). Phylogenetic analyses were conducted using Bayesian inference (BI) and maximum likelihood (ML) methods. ITS and trnL-F datasets were used to construct the ML tree independently to evaluate the congruence between two makers. As there were no hard incongruences (Nishii et al. 2015), we performed the following analysis using a combined dataset. Best-fit DNA substitution models were selected using the Akaike Information Criterion (AIC) in Modeltest v 2.7 (Posada and Crandall 1998). Modeltest determined the best models GTR + G + 1 for the combined dataset. BI analyses were based on a Markov chain algorithm implemented in MRBAYES 3.2.6 (Huelsenbeck and Ronquist 2001). Four chains of the Markov chain Monte Carlo (MCMC) simulation were performed for 4,000,000 generations, each with trees sampled every 100 generations. After discarding the first 25% of the trees, the retained ones were used to calculate the node probability (posterior probability). ML analyses with 1000 bootstrap resampling were conducted using an online version of RAxML-HPC2 v8.2.10 (Stamatakis et al. 2008), available at (http://www.phylo.org/index.php/portal/) (Miller et al. 2010) with the gamma model of rate heterogeneity.
Chromosome preparations
Leaf cuttings yielded new root tips when grown hydroponically for 2–3 weeks. The new root tips were then pretreated with a solution of 0.002 mol·L-1 8-hydroxyquinoline at 13 °C for 4–5 h. After fixation for 24 h by Carnoy solution (3:1 ethanol: acetic acid) at 4 °C, dissociate, stain, and squash methods followed (Jong and Möller 2000, Christie et al. 2012). The chromosome numbers were determined in at least 20 cells from 10 different root tips with well-spread chromosomes in metaphase and captured using a light microscope (Leica DM 2500, camera Leica DFC420).
Michaelmoelleria vietnamensis
 Figure 5. Photos of Cathayanthe biflora Chun, the related genus/species of Michaelmoelleria vietnamensis F. Wen, Z.B. Xin & T.V. Do A habitat B cyme and frontal view of flower C cyme and lateral view of flower D fruit. Photos by Fang Wen, arranged by Wen-Hua Xu.
T.grandiflora
Figure 6. Photos of Deinostigma W.T.Wang & Z.Y.Li (A–E) and Tribounia D.J.Middleton (F–I), the morphologically similar genera and species of Michaelmoelleria F.Wen, Y.G.Wei & T.V.Do (M. vietnamensis F.Wen, Z.B.Xin & T.V.Do) A Deinostigma eberhardtii (Pellegr.) D.J.Middleton & H.J.Atkins B D. tamiana (B.L.Burtt) D.J.Middleton & H.J.Atkins C D. cycnostyla (B.L.Burtt) D.J.Middleton & H.J.Atkins D D. cicatricosa (W.T.Wang) D.J.Middleton & Mich.Möller ED. cyrtocarpa (D.Fang & L.Zeng) Mich.Möller & H.J.Atkins F–G Tribounia venosa (Barnett) D.J.Middleton H–I T.grandiflora D.J.Middleton. A–E photos by Fang Wen F–I photos by David Middleton, arranged by Wen-Hua Xu.
Results
Discussion
In March 2018, a plant having bluish-purple flowers of Gesneriaceae was collected in southern Vietnam. Neither the collectors nor the researchers on the family were able to allocate it to any known genus at that time. Collectors once thought that it might be a member of Deinostigma because this genus is distributed from South China to Central Vietnam (Möller et al. 2016), and shows superficial similarities to Deinostigma in general appearance. For example, the caulescent habit (D. cicatricosa, D. cyrtocarpa, D. minutihamata(D.Wood) D.J.Middleton & H.J.Atkins), usually more and less fleshy leaves (in most Deinostigma species except three species as mentioned above) and fleshy stems, but differs in long and zigzag narrowly infundibuliform corolla tube, four fertile stamens and two lingulate stigmas. The other morphological similar genus is Tribounia, a genus endemic to Thailand (Middleton and Möller 2012). The two genera share the characters of zigzag corolla tube and rounded corolla lobes but can be distinguished by the number of fertile stamens. Based on those morphological characters above, we confirmed that it does not belong to Deinostigma or Tribounia. Furthermore, after consulting the related literature (Burtt 1954, 1963; Wang et al. 1990, 1998; Li and Wang 2005; Weber et al. 2011c, 2013), we also could not find any genus in which to place this unknown species.
The phylogenetic relationship was largely congruent with previous studies (Möller et al. 2009, 2011a, 2016; Middleton et al. 2015, 2018). Michaelmoelleria vietnamensis and its morphologically similar genus Deinostigma is recovered within a polytomy but the phylogenetic relationship of them is distant. It also shows a more distant relationship between Michaelmoelleria vietnamensis and the other similar genus Tribounia. However, our analyses of DNA sequence data suggest that Michaelmoelleria vietnamensis is closely related to the genus Cathayanthe with strong support (PP = 1, BS = 100) and both of them sister to the clade comprised of the genera of Allocheilos, Gyrocheilos, Liebigia, and Didymocarpus with strong support of BI analysis (PP = 0.99) but weak support of ML analysis (BS = 69). Morphologically, Michaelmoelleria vietnamensis, which represents this new genus endemic to Vietnam, can be easily distinguished from the genera of Cathayanthe, Allocheilos, Gyrocheilos, Liebigia, and Didymocarpus by these distinct characters: fleshly stem and leaves alternate on elongated aerial stem. In addition, only two genera’s chromosome numbers among above-mentioned genera were reported (Liebigia speciosa (Blume) DC. in Liebigia: 2n = 28 or 32; Didymocarpus ssp.: 2n = 20, 22, 24, 28, 32, 36, 44, 54) (Möller and Pullan 2015onwards; Yang et al. 2019). Furthermore, the chromosome numbers of Allocheilos W.T. Wang (two species, both endemic to China) and Gyrocheilos W.T. Wang (six species and two varieties, distributed from South China to North Vietnam), which are the relative genera of Michaelmoelleria, had never been reported before (Li and Wang 2005; Middleton 2015). The cytological evidence showed 2n = 36, which is the difference from above genera, except Didymocarpus pedicellatus R.Br. (Mehra and Vasudevan 1972; Vasudevan 1976). Building on these, we treat Michaelmoelleria vietnamensis as a distinct genus of tribe Didymocarpeae. All distinguishing characters for identification of Michaelmoelleria, Cathayanthe (Fig. 5), Deinostigma (Fig. 6A–E) and Tribounia (Fig. 6F–I) are listed in Table 1.

Thanks to: Mr. Wen-Hua Xu for his attractive arrangement of photos; Mr. Wuf and Ms. Banbino and VietNam’s Garden (the owner of the Facebook account) for their helpful information about this species and Dr. David Middleton from Singapore Botanic Gardens for his constructive suggestions and photos. This study was financially supported by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 106.03-2019.308, the Fund of Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain (19-050-6), the National Natural Science Foundation of China (31860047), the Natural Science Foundation of Guangxi (2017GXNSFAA198006), Science Research Foundation of Guangxi Academy of Sciences (2017YJJ23022), Guilin Science and Technology Foundation (20180107-6), the Key Sci. & Tech. Research and Development Project of Guangxi (Guike AB16380053). We also wish to thank Michael LoFurno (Adjunct Professor, Temple University) from Philadelphia, USA for his editorial assistance.
Acknowledgments
References
  • Averyanov LV, Loc PK, Hiep NT, Harder DK (2003) Phytogeographic review of Vietnam and adjacent areas of Eastern Indochina. Komarovia 3: 1–83.
  • Bridson D, Forman L (1998) The Herbarium Handbook Royal Botanic Gardens (3rd edn.). Kew: Royal Botanic Gardens, London.
  • Burtt BL (1954) Studies in Gesneriaceae of the Old World. 1: General introduction. Notes from the Royal Botanic Garden Edinburgh 21: 185–192.
  • Burtt BL (1963) Studies in Gesneriaceae of the Old World. XXIV: Tentative keys to the tribes and genera. Notes from the Royal Botanic Garden Edinburgh 24: 205–220.
  • Burtt BL (1977) Classification above the genus, as exemplified by Gesneriaceae, with parallels from other groups. Plant Systematics and Evolution 1(Suppl.): 97–109.
  • Christie F, Barber S, Möller M (2012) New chromosome counts in Old World Gesneriaceae: Numbers for species hitherto regarded as Chirita and their systematic and evolutionary significance. Edinburgh Journal of Botany 69(2): 323–345. https://doi.org/10.1017/S0960428612000169
  • Fu LF, Monro A, Do TV, Nuraliev MS, Averyanov LV, Wen F, Xin ZB, Maisak TV, Kuznetsov AN, Kuznetsova SP, Nguyen KS, Wei YG (2019) Checklist to the Elatostema (Urticaceae) of Vietnam including 19 new records, ten new combinations, two new names and four new synonyms. PeerJ 7: e6188. https://doi.org/10.7717/peerj.6188
  • Ho PH (2000) An Illustrated Flora of Vietnam. Vol. 3. Tre Ho Chi Minh City Press, Ho Chi Minh, Vietnam. [in Vietnamese]
  • Jong K, Möller M (2000) New chromosome counts in Streptocarpus (Gesneriaceae) from Madagascar and the Comoro Islands and their taxonomic significance. Plant Systematics and Evolution 224: 173–182. https://doi.org/10.1007/BF00986341
  • Kearse M, Moir R, Wilson A, Stones-Havas S, Cheung M, Sturrock S, Buxton S, Cooper A, Markowitz S, Duran C, Thierer T, Ashton B, Meintjes P, Drummond A (2012) Geneious Basic: An integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics (Oxford, England) 28(12): 1647–1649. https://doi.org/10.1093/bioinformatics/bts199
  • Li ZY, Wang YZ (2005) Plants of Gesneriaceae in China. Henan Science and Technology Publishing House, Zhengzhou.
  • Middleton DJ, Triboun P (2012) Somrania, a new genus of Gesneriaceae from Thailand. Thai Forest Bulletin (Botany) 40: 9–13.
  • Middleton DJ, Atknis H, Truong LH, Nishii K, Möller M (2014) Billolivia, a new genus of Gesneriaceae from Vietnam with five new species. Phytotaxa 161(4): 241–269. https://doi.org/10.11646/phytotaxa.161.4.1
  • Middleton DJ, Nishii K, Puglisi C, Forrest LL, Möller M (2015) Chayamaritia (Gesneriaceae: Didymocarpoideae), a new genus from Southeast Asia. Plant Systematics and Evolution 301(7): 1947–1966. http://doi.10.1007/s00606-015-1213-2
  • Middleton DJ, Khew GS, Poopath M, Puglisi C, Möller M (2018) Rachunia cymbiformis, a new genus and species of Gesneriaceae from Thailand. Nordic Journal of Botany 36(11): e01992. http://doi.10.1111/njb.01992
  • Middleton DJ, Armstrong K, Baba Y, Balslev H, Chayamarit K, Chung RCK, Conn BJ, Fernando ES, Fujikawa K, Kiew R, Luu HT, Aung MM, Newman MF, Tagane S, Tanaka N, Thomas DC, Tran TB, Utteridge TMA, van Welzen PC, Widyatmoko D, Yahara T, Wong KM (2019) Progress on Southeast Asia’s Flora projects. Gardens’ Bulletin Singapore 71(2): 267–319. http://doi.10.26492/gbs71(2).2019-02
  • Miller MA, Pfeiffer W, Schwartz T (2010) Creating the CIPRES Science Gateway for inference of large phylogenetic trees. Proceedings of the Gateway Computing Environments Workshop (GCE), 2010. Institute of Electrical and Electronics Engineers, New Orleans, 1–8.
  • Möller M, Pullan M (2015 onwards): RBGE WebCyte2 – An updated Gesneriaceae cytology database.
  • Möller M, Pfosser M, Jang CG, Mayer V, Clark A, Hollingsworth ML, Barfuss MHJ, Wang YZ, Kiehn M, Weber A (2009) A preliminary phylogeny of the ‘didymocarpoid Gesneriaceae’ based on three molecular data sets: Incongruence with available tribal classifications. American Journal of Botany 96(5): 989–1010. https://doi.org/10.3732/ajb.0800291
  • Möller M, Forrest A, Wei YG, Weber A (2011a) A molecular phylogenetic assessment of the advanced Asiatic and Malesian didymocarpoid Gesneriaceae with focus on non-monophyletic and monotypic genera. Plant Systematics and Evolution 292(3–4): 223–248. https://doi.org/10.1007/s00606-010-0413-z
  • Möller M, Middleton D, Nishii K, Wei YG, Sontag S, Weber A (2011b) A new delineation for Oreocharisincorporating an additional ten genera of Chinese Gesneriaceae. Phytotaxa 32(1): 1–36. https://doi.org/10.11646/phytotaxa.23.1.1
  • Möller M, Nishii K, Atkins HJ, Kong HH, Kang M, Wei YG, Wen F, Hong X, Middleton DJ (2016) An expansion of the genus Deinostigma (Gesneriaceae). Gardens’ Bulletin Singapore 68(1): 145–172. http://doi.10.3850/S2382581216000119
  • Nishii K, Hughes M, Briggs M, Haston E, Christie F, DeVilliers JM, Hanekom T, Roos GW, Bellstedt UD, Möller M (2015) Streptocarpus redefined to include all Afro-Malagasy Gesneriaceae: Molecular phylogenies prove congruent with geography and cytology and uncovers remarkable morphological homoplasies. Taxon 64: 1243–1274. https://doi.org/10.12705/646.8
  • Phuong VX (2005) Checklist of plant species in Vietnam. Vol. 3. Agriculture Press, Ha Noi.
  • Puglisi C, Middleton DJ, Triboun P, Möller M (2011) New insights into the relationships between Paraboea, Trisepalum and Phylloboea (Gesneriaceae) and their taxonomic consequences. Taxon 60(6): 1693–1702. https://doi.org/10.1002/tax.606014
  • Sun YX, Moore MJ, Landis JB, Lin N, Chen L, Deng T, Zhang JW, Meng AP, Zhang SJ, Tojibaev KS, Sun H, Wang HC (2018) Plastome phylogenomics of the early-diverging eudicot family Berberidaceae. Molecular Phylogenetics and Evolution 128: 203–211. https://doi.org/10.1016/j.ympev.2018.07.021
  • Thiers B (2016) Index Herbariorum: A Global Directory of Public Herbaria and Associated Staff. New York Botanical Garden’s Virtual Herbarium. http://sweetgum.nybg.org/science/ih/
  • Thiers BM (2019) The world’s herbaria 2018: A summary report based on data from Index Herbariorum. William and Lynda Steere Herbarium, The New York Botanical Garden. http://sweetgum.nybg.org/science/ih/
  • Vasudevan KN (1976) Contribution to the cytotaxonomy and cytogeography of the flora of the western Himalayas: With an attempt to compare it with the flora of the Alps III. Bulletin de la Société Botanique Suisse 8: 152–203.
  • Wang WT, Pan KY, Li ZY (1990) Gesneriaceae. In: Wang WT (Ed.) Flora Reipublicae Popularis Sinicae (Vol. 69). Science Press, Beijing, 141–271.
  • Wang WT, Pan KY, Li ZY, Weitzman AL, Skog LE (1998) Gesneriaceae. In: Wu ZY, Raven PH (Eds) Flora of China (Vol. 18). Science Press, Beijing, & Missouri Botanical Garden Press, St. Louis, 244–401.
  • Weber A, Wei YG, Sontag S, Möller M (2011b) Inclusion of Metabriggsia into Hemiboea (Gesneriaceae), with notes on carpel reduction and its functional background. Phytotaxa 23: 37–48.
  • Weber A, Middleton DJ, Forrest A, Kiew R, Lim CL, Rafidah AR, Sontag S, Triboun P, Wei YG, Yao TL, Möller M (2011c) Molecular systematics and remodeling of Chirita and associated genera (Gesneriaceae). Taxon60(3): 767–790. https://doi.org/10.1002/tax.603012
  • Weber A, Clark JL, Möller M (2013) A new formal classification of Gesneriaceae. Selbyana 31(2): 68–94.
  • Wei YG, Wen F, Möller M, Monro A, Zhang Q, Gao Q, Mou HF, Zhong SH, Cui C (2010) Gesneriaceae of South China. Guangxi Science and Technology Publishing House, Nanning, Guangxi.
  • Wei YG, Wen F, Zhao B, He SZ (2013) Anna rubidiflora (Gesneriaceae), a new species from Guizhou, the southern part of China. Plant Ecology and Evolution 146(2): 203–211. https://doi.org/10.5091/plecevo.2013.731
  • Wen F, Li S, Xin ZB, Fu LF, Hong X, Cai L, Qin JQ, Pan B, Pan FZ (2019) The updated plant list of Gesneriaceae in China under the new Chinese naming rules. Guangxi Sciences 26(1): 37–63.
  • Yang LH, Feng C, Xu MZ, Sun ZX, Kang M (2019) Synopsis of Cytological Studies on Didymocarpoideae(Gesneriaceae) under New Classification System. Redai Yaredai Zhiwu Xuebao 27(5): 548–557.

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