Reproductive development and genetic structure of the mycoheterotrophic orchid Pogoniopsis schenckii Cogn.

Author(s)

Alves, Mariana Ferreira ^[1] ; Pinheiro, Fabio ^[1] ; Pereira Nunes, Carlos Eduardo ^[1] ; Prosdocimi, Francisco ^[2] ; Sarzi, Deise Schroder ^[2] ; Furtado, Carolina ^[3] ; Sampaio Mayer, Juliana Lischka ^[1]

Affiliation

^[1] Univ Estadual Campinas, Inst Biol, Dept Biol Vegetal, Sao Paulo - Brazil

^[2] Univ Fed Rio de Janeiro, Inst Bioquim Med Leopoldo Meis, Lab Genom & Biodiversidade, Rio De Janeiro - Brazil

^[3] Inst Nacl Canc, Dept Genet, Rio De Janeiro - Brazil

• Document type: Journal article
• Source: BMC PLANT BIOLOGY; v. 21, n. 1 JUL 12 2021.
• Web of Science Citations: 1

Abstract

Background Pogoniopsis schenckii Cogn. is a mycoheterotrophic orchid that can be used as a model to understand the influence of mycoheterotrophy at different stages of the reproductive cycle. We aimed to verify the presence of endophytic and epiphytic fungi at each stage of the reproductive process and investigated how the breeding system may relate to genetic structure and diversity of populations. In this study we performed anatomical and ultrastructural analyses of the reproductive organs, field tests to confirm the breeding system, and molecular analysis to assess genetic diversity and structure of populations. Results During the development of the pollen grain, embryo sac and embryogenesis, no fungal infestation was observed. The presence of endophytic fungal hyphae was observed just within floral stems and indehiscent fruit. Beyond assuring the presence of fungus that promote seed germination, specific fungi hyphae in the fruit may affect other process, such as fruit ripening. As other mycoheterotrophic orchids, P. schenckii is autogamous, which may explain the low genetic diversity and high genetic structure in populations. Conclusions We discuss an interesting interaction: fungal hyphae in the indehiscent fruit. These fungal hyphae seem to play different roles inside fruit tissues, such as acting in the fruit maturation process and increasing the proximity between fungi and plant seeds even before dispersion occurs. As other mycoheterotrophic orchids, P. schenckii is autogamous, which may explain the low genetic diversity and high genetic structure in populations. Altogether, our findings provide important novel information about the mechanisms shaping ecology and evolution of fragmented populations of mycoheterotrophic plant. (AU)

• FAPESP's process: 16/22785-8 - The role of habitat selection in the maintenance of species integrity in natural hybrid zones
• Grantee: Fábio Pinheiro
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 15/26479-6 - Vegetative structure of the achlorophyllous orchid Pogoniopsis schenckii (Vanilloideae) and its interaction with mycorrhizal fungi
• Grantee: Juliana Lischka Sampaio Mayer
• Support Opportunities: Regular Research Grants