Evidence of a Possible Double Hybrid Origin for Two Malagasy Species of Piper L. (Piperaceae)

Abstract

two new species of genus Piper L. from Madagascar: Piper malgassicum and Piper tsarasotrae, were analyzed to investigate their phylogenetic position and evolutionary history. Both plastidial and nuclear markers were used for sequencing. The plastidial markers (ndhF and the trnL intron) showed a close relationship between the two species with respect to the other species of Piper. Both species appeared phylogenetically related to the African P. guineense and the Malagasian/Mascarenhas endemic P. borbonense. The nuclear marker (G3PDH) amplification produced two separate sets of sequences: “long” sequences, that could be easily translated into an amino acid chain, and “short” sequences, characterized by deletions that did not allowed to translate them correctly to an amino acid sequence. Analyzing together the nuclear sequences, we observed that the “long” sequence of P. tsarasotrae had a stricter relationship to the African accessions of P. guineense, while the accession of P. malgassicum was more strictly related to P. borbonense. On the contrary both “short” sequences of Piper malgassicum and Piper tsaratsotrae resulted phylogenetically related to Asian accessions and more distantly related to the formerly cited species. This unexpected result was tentatively explained with a more ancient hybridization event between an ancestor of P. malgassicum and P. tsarasotrae (and possibly P. borbonense) and an Asian species of Piper. The Asian contribution would have produced the ancestors of the “short” sequences that would eventually have lost functionality by deletions, becoming paralogs. A more recent hybridization event would have led to the separation of Piper malgassicum from Piper tsarasotrae with an African pollen-derived genome contribution from P. guineense or, more probably, an ancestor thereof, to an ancestor of P. tsarasotrae. The chromosome numbers of P. tsarasotrae (2n = about 38) and P. malgassicum (2n = about 46), were more like the Asian species than to the American species. Unfortunately, no chromosome number of the African species P. guineense is currently available, to analyze eventual chromosomal connections.

Histochemical observations in Piper malgassicum (Piperaceae) with a special focus on the epidermis

“…Most authors studying the genus Piper from a phytochemical point of view focussed their attention on the fruit, since it is the most relevant part of the plant for economical purposes. Our observations on the leaves are in agreement with other authors who showed these phytochemical features in other species of the Piper genus (Marinho et al 2011;Pires Jacinto et al 2018;Silva et al 2017;Bertocco et al 2017) From a phytochemical point of view, P. malgassicum is closely related to P. nigrum (Palchetti et al 2018(Palchetti et al , 2020 and used traditionally in the same way as a spice.…”

“…In this contribution, we investigated the vegetative structures and the localization of secondary metabolites of a recently described species of the genus Piper L. from Madagascar, P. malgassicum Papini, Palchetti, Gori & Rota Nodari (Palchetti et al 2018, 2020, which is used for the production of local pepper named "voatsiperifery", probably mixed with P. borbonense (Miq.) C. DC.…”

<em>Piper</em> species (Piperaceae) of Sri Lanka and the diversity of the economically important <em>Piper nigrum</em> (black pepper): An overview of what has been done and what is yet to be achieved

“…The origin and evolution of Piper in Peninsular India were investigated using nrITS and plastid intron psbJ-petA (Sen et al, 2019). The plastid markers ndhF and trnL intron showed a close relationship of the two Malagasy species with the African P. guineense, but the sequencing of the nuclear G3pdh gene showed some hybridization and introgression with Asian and African species (Palchetti et al, 2020). In addition to DNA sequencing, molecular markers such as RAPD (randomly amplified polymorphic DNA) have been used to characterize genetic diversity among six species of Piper (Shivashankar, 2014).…”