Abstract Detail

Systematics

Nickrent, Daniel L [1], Neubig, Kurt Maximillian [2], Su, Huei-Jiun [3].

Multigene phylogeny places Brachynema in Erythropalaceae (Santalales).

Past molecular phylogenetic analyses have advanced our understanding of relationships within the sandalwood order (Santalales), however, one genus has remained unplaced: Brachynema. In 1857, Bentham described the first species, B. ramiflorum from Brazil, and since then one additional species, B. axillare from northern South America, has been described. Its ordinal and familial placement has been enigmatic, including Ebenaceae, Linaceae, Icacinaceae, Lecythidaceae, and Olacaceae s.l. Sequences of nuclear SSU and LSU ribosomal DNA, chloroplast rbcL, matK and accD and mitochondrial matR were obtained for 170 members of Santalales. The analysis included one sample of B. ramiflorum collected July 1980 (Pará, Brazil, C. A. Cid Ferreira 1482, NY). The total DNA obtained from this herbarium specimen was subjected to genome skimming using an Illumina HiSeq which provide complete sequences of the above six genes. A concatenated data set was analyzed with maximum parsimony and likelihood. All separate gene partitions and the concatenated data set yielded the same result: Brachynema is sister to Maburea trinervis (Erythropalaceae), a monospecific shrub from Guyana first described in 1992 by Maas et al. This result is fascinating because Brachynema displays a number of morphological features that are aberrant in the order: glandular-dentate leaf margins, upper and lower pulvinar thickenings, and a 4-5 chambered ovary with axile placentation (1 ovule pendulous in each locule). Placentation in nearly all members of Santalales is free-central with apical, pendulous ovules; however, Maburea was described as being 2-3 locular, also with axile placentation (1-2 somewhat pendulous ovules per locule). Leaf anatomical characters are notably similar between the two genera. This study demonstrates how particular suites of morphological characters support affinities that are in conflict with strongly supported molecular phylogenetic results.

1 - Southern Illinois University, Department Of Plant Biology, 1125 Lincoln Drive, CARBONDALE, IL, 62901-6509, USA
2 - Southern Illinois University Carbondale, Plant Biology, Carbondale, IL, 62901, USA
3 - National Taiwan University, Institute of Ecology and Evolutionary Biology, Life Science Building R1227, Roosevelt Road Section 4, Taipei, Taiwan

Keywords:
phylogeny
genome skimming.

Presentation Type: Oral Paper
Session: 41, Basal Rosids & Rosids I
Location: 101/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 8:45 AM
Number: 41004
Abstract ID:417
Candidate for Awards:None