Cycad population genomics and chemical diversity (funded by SENACYT 2018-2020)
The extinction risk in tropical regions is elevated due to anthropogenic activities. The genetic diversity of tropical plants, their endophytes and their chemical richness has been extensively studied in flowering plants. On the contrary, the tropical gymnosperms (e.g. conifers, cycads) have been largely understudied. Cycads represent a unique lineage of gymnosperms, with fossil records dated from the Permian (~250 Ma). Besides the evolutionary importance of the group, some species have a great impact on human health, due to the accumulation of cyanide compounds (amino acid ß-methyloamino-L-alanine, BMAA), produced by symbiotic cyanobacteria lodged inside their roots, the compounds bio accumulate in their seeds eventually consumed by local communities in remote tropical regions. In addition, preliminary data have identified a suite of endophytes (fungi and bacteria) that could potentially contribute to the production of secondary metabolites. Cycads are also known for their aesthetic value and each individual plant could be valued in hundreds of dollars in the legal and illegal market. All these factors along with the increasing deforestation and the urban and mining development threaten the species habitats, without a basic knowledge of their genetic and chemical diversity. Panamá is country particularly vulnerable for the illegal trade of cycads, because of strategic geopolitical position. In Panama, there exist 15-17 species of the genus Zamia, with 65% of endemism, including the only epiphytic gymnosperm, Z. pseudoparasitica. The species is particularly abundant in the mining region of Donoso, eastern Panama.
In this project, we will be focusing on the genetic and chemical diversity of Panamanian cycad endemic species and their endophytes. The data recovered from the study will be essential to undertake effective programs of demographic and genetic rescue. Additionally, using modern techniques such as molecular chemical networking will help us to evaluate the chemical composition and potential human use of all 17 species.
This project is done in collaboration with scientists of two Panamanian institutions: INDICASAT and Universidad de Panamá, with all molecular work to be carried out at the STRI. The study will provide the baseline for the conservation of the genetic and chemical diversity of Central American local flora. The project is done in collaboration with Dr. Kristin Saltonstall (STRI), Rita Bethancourt (UP), Ariadna Bethancourt (UP), Armando Durant (INDICASAT) and Brian Sedio (STRI, U. of Austin, Texas).
Genome scale study of symbiosis between plants and nitrogen-fixing bacteria and tropical diversity- The Panama case (Funded by STRI, 2015-2019) and SENACYT (2018-2020)
Hornworts are arguably the oldest land plant lineage involved in an obligatory symbiosis with cyanobacteria of the genus Nostoc. Most hornworts have globose colonies while the sister species to all other hornworts, Leiosporoceros dussii, has bifurcating cyanobacterial strands locked inside the thallus. In cycads, the cyanobionts form a dark band between the inner and outer cortex of the roots, with elongated cortical cells, presumably related to metabolite transport, interconnecting the two partners. The Panamanian project focuses on the hornwort Leiosporoceros dussii and two endemic Zamia species, Zamia nana (terrestrial) and Zamia pseudoparasitica, the only epiphytic gymnosperm. We have RNA seq data and genomic data of axenic (sterile) plants and plants re-infected in-vitro with cultured cyanobacteria. Additionally, we have gathered sequences from the genomic regions rbcL-rbcX, 16S, ITS and trnL intron to investigate the genetic diversity of Panamanian cyanobacteria, other bacteria and endophytic fungi.
The research addresses three contemporary topics in evolutionary biology. First, mRNA sharing is a likely mechanism for horizontal gene transfer. Second, horizontal gene transfer has been highlighted as a fundamental drive in the evolution of prokaryotes and eukaryotes (Cooper, Current Biol., 2013). Third, our study will start to uncover the genetic diversity of symbionts in the tropics, providing a new dimension to tropical studies on plant-cyanobacterial symbiosis. This is research is done in conjunction with Noris Salazar Allen and José Gudiño (STRI) and two undergraduates (Maycol Madrid and Yessenia Guadalupe, Univ. Panamá and STRI) and Fay-Wei Li (Cornell University).
Functional diversity of nitrogen-fixing bacteria associated to Panamanian cycads, especially Zamia pseudoparasitica, the only epiphytic gymnosperm, project by Philip Bell-Doyon
Functional genomics of the symbiotic association between the Panamanian cycads and cyanobacteria, project by JCVA