Soil Microbiome Influences on Seedling Establishment and Growth of Prosopis chilensis and Prosopis tamarugo from Northern Chile

Prosopis chilensis and Prosopis tamarugo, two woody legumes adapted to the arid regions of Chile, have a declining distribution due to the lack of new seedling establishment. This study investigated the potential of both species to establish in soil collected from four locations in Chile, within and outside the species distribution, and to assess the role of the root-colonizing microbiome in seedling establishment and growth. Seedling survival, height, and water potential were measured to assess establishment success and growth. 16S and ITS2 amplicon sequencing was used to characterize the composition of microbial communities from the different soils and to assess the ability of both Prosopis species to recruit bacteria and fungi from the different soils. Both species were established on three of the four soils. P. tamarugo seedlings showed significantly higher survival in foreign soils and maintained significantly higher water potential in Mediterranean soils. Amplicon sequencing showed that the four soils harbored distinct microbial communities. Root-associated microbial composition indicated that P. chilensis preferentially recruited mycorrhizal fungal partners while P. tamarugo recruited abundant bacteria with known salt-protective functions. Our results suggest that a combination of edaphic properties and microbial soil legacy are potential factors mediating the Prosopis establishment success in different soils

Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Background: "Garra de Leon" (Leontochir ovallei) is an ephemeral endangered Alstroemeriaceae species endemic to Chile. Despite many efforts to improve the conservation of this species, the stimulation of dormant seeds and the production of rhizomes under controlled conditions remain unexplored. The aims of this study were to examine the germination responses of L. ovallei seeds under different in vitro conditions and to evaluate the formation of viable rhizomes after transplantation from in vitro to ex vitro conditions. Methods: We evaluated five in vitro seed germination treatments: (1) acid scarification, (2) acid scarification followed by imbibition of seeds in aerated water, (3) imbibition of seeds in gibberellic acid, (4) clipping of seeds with a scalpel, and (5) seeds without any treatment (control). Seedlings obtained under in vitro conditions were transplanted to ex vitro conditions following a gradual acclimation process. After eight months, the number of rhizomes per plant was counted. To test asexual multiplication, each rhizome with its respective storage organ was divided using a scalpel and then left to rest for two years before subsequent evaluation of viability. After that period, the rhizomes were re-hydrated, and the emergence of plants after three months was evaluated. Results: Seeds exposed to treatment 2 showed the highest germination percentage (36%), followed by the seeds whose coats were clipped (14%) and seeds treated with sulphuric acid (8%). The seed germination of the control treatment was 3%. After transplantation to ex vitro conditions, we obtained 220 rhizomes, with an average of three to six rhizomes per plant. After two years of dormancy, a total of 34 rhizomes (of 220 rhizomes) reactivated growth after re-ydration, indicating that, at least, 15,5% responded positively to watering. Conclusions: We found that the seed germination of L. ovallei was increased by strong acidic conditions, suggesting that the main type of seed dormancy in this species is physical. However, germination was further increased by aeration, indicating embryo dormancy. In addition, we were able to obtain viable rhizomes by transplanting seedlings from in vitro to ex vitro conditions, which may be helpful for the propagation and ex situ conservation of this rare geophyte of Chile and potentially other geophyte species adapted to wet-dry cycle environment

Disease Prevention: An Opportunity to Expand Edible Plant-Based Vaccines?

The lethality of infectious diseases has decreased due to the implementation of crucial sanitary procedures such as vaccination. However, the resurgence of pathogenic diseases in different parts of the world has revealed the importance of identifying novel, rapid, and concrete solutions for control and prevention. Edible vaccines pose an interesting alternative that could overcome some of the constraints of traditional vaccines. The term “edible vaccine” refers to the use of edible parts of a plant that has been genetically modified to produce specific components of a particular pathogen to generate protection against a disease. The aim of this review is to present and critically examine “edible vaccines” as an option for global immunization against pathogenic diseases and their outbreaks and to discuss the necessary steps for their production and control and the list of plants that may already be used as edible vaccines. Additionally, this review discusses the required standards and ethical regulations as well as the advantages and disadvantages associated with this powerful biotechnology tool

Additional file 4: of Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Monthly distribution of temperatures (T) and relative humidity (RH) in La Serena during years the 2014, 2015 and 2016. Data were obtained from Meteorological Station “La Serena”, which is controlled by the Center for Advanced Studies in Arid Areas (CEAZA, www.ceazamet.cl ). This station is installed at 50 meters from where this study was performed. (DOCX 16 kb

Additional file 3: of Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Rhizome production and multiplication of L. ovallei rhizomes. A) Rhizomes obtained from an eight-month old seedling. Bar = 1 cm. B) Eight rhizomes each with its food storage organ obtained from one plant. Bar = 1 cm. C) Rhizome dissection using a scalpel. Bar = 1 cm. D) Dormant rhizomes of L. ovallei reactivated after two years of resting. Bar = 1 cm. (JPG 1675 kb

Additional file 1: of Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Graphical diagram showing the methodology applied for the sexual and asexual propagation of L. ovallei. A) Inflorescences of L. ovallei growing in Llanos de Challe National Park in November 2011. Bar = 10 cm. B) Inflorescence of L. ovallei covered with a paper bag (December 2011). Bar = 5 cm. C) Healthy state of inflorescences and their seeds after two months covered with the paper bag (February 2012). Bar = 1 cm. D) One-month old seedling growing inside a petri dish. Bar = 1 cm. E) Three-month old seedlings transplanted to ex vitro conditions. Young seedlings were covered with a plastic cup to protect them against dehydration; this plastic cup was opened to permit aeration. Bar = 2 cm. F) Group of acclimated five-month old seedlings. Bar = 5 cm. (JPG 1867 kb

Additional file 5: of Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Physico-chemical analysis of La Serena tap water*. (DOCX 16 kb

Additional file 2: of Sexual and asexual reproductive aspects of Leontochir ovallei, a rare and endangered geophyte of the Atacama Desert

Information on the baseline conditions used for in vitro seed germination analysis of L. ovallei seeds. Both in vitro cultivation conditions and pre-sowing treatments were evaluated using approximately 4000 seeds in total. (DOCX 18 kb