Origin and genetic variability of the invasive species Stellaria media (Caryophyllaceae) through morphological traits and molecular markers

BREM, MARTA CAROLINA; FORTUNATO, FIAMA ; COULLERI, JUAN PABLO

Puerto Iguazú

Simposio; XVI International Symposium on Biological Control of Weeds; 2023

ISBCW

Stellaria media (“Capipi”, “chickweed”) is a species native to Europe, West Asia andNorth Africa that behaves as a weed in barley, wheat, rye, soybean and sunflower crops.This species accumulates nitrates at potentially toxic levels for animals and is highlyresistant to different herbicides. Moreover, it has several mechanisms that determine itsinvasive character, such as: high tolerance to water stress, high production of flowersand seeds per plant with high germination power and different seed dispersalmechanisms. The objectives of this work are to: (1) evaluate the variation inmorphological traits of S. media in Argentina and (2) estimate the origin of itspopulations in our country from a phylogeographic analysis with nuclear sequences,ITS1 and ITS2. The observation of vegetative and reproductive structures was carriedout from living material, fixed in with formaldehyde-aceticacid-ethanol (FAA) and/orherbarium specimens, using a stereoscopic microscopy and an ANOVA was performedto estimate the morphological variability. For the phylogeographic analysis, ITSsequences were obtained by PCR from four populations from the NEA (Northeastern)and NOA (Northwestern) regions and Buenos Aires Province, and those available inGenebank belonging to Canada (four populations), China (three populations), CzechRepublic (four populations), England (four populations), Germany (two populations),South Korea (three populations) and United States of America (two populations). Thesequences were aligned and analysed by maximum parsimony in MEGA X, to root thetree a Spergula arvensis ITS sequence was used. The ANOVA shows the presence ofsignificant differences between study areas in plant height, degree of pubescence, leafarea (length x width of lamina), fruit size (length x width of capsule) and number ofseeds. The phylogeographic analyses indicate that the Argentinian populations ofStellaria media present multiple origins, probably from North America, England orEastern Europe. This would also indicate that the invasive process could have been theresult of several introduction events, which is consistent with the morphologicalvariability observed.