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The region of Arica and Parinacota hosts unexplored remote sites with unique characteristics suitable for developing novel agricultural bioproducts. Notable locations include Jurasi Hot Springs, Polloquere Hot Springs, and Amuyo Lagoons, featuring open pools fed by thermal mountain springs. These geothermal sites harbor bacteria with plant growth-promoting activities, particularly interesting to the strains J19, TP22, A20, and A3. These bacteria possess in vitro plant growth-promoting traits, the ability to produce hydrolytic enzymes, and the capacity to inhibit phytopathogenic fungi. Moreover, they can tolerate different concentrations of NaCl and boron, making them suitable for developing new agricultural bioproducts for arid environments. The bacterial strains A3 and A20 have a positive effect on the growth of the aerial part of tomato plants (increased stem length, fresh and dry weight), with a significant increment in proline concentration and chlorophyll A and B content under saline conditions. Meanwhile, the strains J19 and TP22 exhibit herbicidal activity against Cenchrus echinatus by reducing root elongation and germination of the weed. These strains possess plant growth-promoting traits and improve plant resistance to salinity stress. They are promising candidates for developing innovative bio-based agricultural products suited to arid and semi-arid regions.

Malesherbia auristipulata is an endemic plant species of the Atacama Desert, with unique morphological and physiological adaptations. This research was conducted at Cuesta El Águila, Arica and Parinacota Region, Chile. Adult and juvenile plants were monitored, recording their growth, flowering, and fruiting phases. Additionally, plant community species were identified. For the study of endophytic mycoflora, samples of seeds, roots, stems, and leaves were collected, disinfected, and cultivated in specific media. The isolated fungi were analyzed morphologically and molecularly, determining their distribution in different plant organs. The diversity of endophytic fungi associated with M. auristipulata and the associated fungal community was determined. The presence of endophytic fungi varied depending on the organ studied, suggesting dynamic interactions in the structure of its fungal community. Among the identified endophytic fungi, Alternaria sorghi , A. alstroemeriae , and Fusarium nurragi stand out for their presence in the root and stem of the plant. Of particular interest is the presence of F. circinatum in the leaves. This study provides valuable information for the conservation of M. auristipulata and other organisms in the Atacama Desert, highlighting the importance of ecological interactions in the resilience of plants to extreme environmental conditions.

Neltuma alba (Algarrobo blanco), Neltuma chilensis (Algarrobo Chileno) and Strombocarpa strombulifera (Fortuna) are some of the few drought resistant trees and shrubs found in small highly fragmented populations, throughout the Atacama Desert. We reconstructed their plastid genomes using de novo assembly of paired-end reads from total genomic DNA. We found that the complete plastid genomes of N. alba and N. chilensis are larger in size compared to species of the Strombocarpa genus. The Strombocarpa species presented slightly more GC content than the Neltuma species. Therefore, we assume that Strombocarpa species have been exposed to stronger natural selection than Neltuma species. We observed high variation values in the number of cpSSRs (chloroplast simple sequence repeats) and repeated elements among Neltuma and Strombocarpa species. The p-distance results showed a low evolutionary divergence within the genus Neltuma, whereas a high evolutionary divergence was observed between Strombocarpa species. The molecular divergence time found in Neltuma and Strombocarpa show that these genera diverged in the late Oligocene. With this study we provide valuable information about tree species that provide important ecosystem services in hostile environments which can be used to determine these species in the geographically isolated communities, and keep the highly fragmented populations genetically healthy., (© 2024. The Author(s).)

The Region of Arica and Parinacota (Atacama Desert) offers several unexplored remote sites with unique characteristics that would allow for the formulation of new bioproducts for agriculture. Among them, Jurasi Hot Springs, Polloquere Hot Springs, and Amuyo Lagoons represent a group of open pools fed by thermal water springing from the mountains. Their microbiomes remain unspecified, providing a unique opportunity to characterize the endemic community of these sites and develop new bioproducts for sustainable agriculture. Bacteria were isolated from the sediments of these geothermal sites and characterized by sequencing the 16S rRNA gene, microbiological characterization, and agricultural functional characterization. A total of 57 bacteria were isolated from three geothermal sites north of the Atacama Desert. The sequence analysis showed that the isolates belong to several bacterial genera, including Pantoea , Bacillus , and Pseudomonas , among others. The functional characterization revealed the presence of PGP traits, hydrolytic enzymes, and biocontrol activity against phytopathogenic fungi. These bacteria possess the potential to develop new biobased products for agriculture in arid conditions.

Dione ( Agraulis ) dodona (Nymphalidae: Heliconiinae) is a butterfly restricted to the western slopes of the Andes of Peru and Chile and is associated with Malesherbia tenuifolia in xerophytic environments. In this study, we found six additional species of host plants for D. ( A. ) dodona belonging to the genus Malesherbia (Passifloraceae). We used mitochondrial DNA sequences (COI) and microsatellites to screen genetic variation and investigate population structure in six geographic disjointed populations of D . ( A .) dodona associated with distinct Malesherbia species. The PCoA analysis based on allele frequencies evidenced a lack of differentiation among populations and a low F ST . The Bayesian cluster analyses revealed the existence of three genetically distinct groups, but almost all individuals present an admixture ancestry. An absence of isolation by distance pattern was observed. Possible scenarios are discussed: a bottleneck or recent colonization from interconnected populations from the south, and ongoing gene flow among local populations by high dispersal through a landscape formed of isolated populations of Malesherbia .

We provide new information on Neotropical Phyllocnistis Zeller (Gracillariidae) associated with Baccharis (Asteraceae) in the Andes region. Two new species are described, P. canta Cerdea Farfn, n. sp. and P. elongata Cerdea Farfn, n. sp., from the western slopes of the Andes of Peru between 2,000 and 3,000 m elevation, both associated with Baccharis latifolia (R.P.) Pers. The type locality of P. baccharidis Hering is confirmed; immature stages were found at 1,300 m feeding on Baccharis tucumanensis Hook. Arn. in Quebrada las Higueras (Tucumn, Argentina). Four new locality records for P. furcata Vargas Cerdea are provided, extending its distribution by 450 km to the north of the type locality.

Tillandsia landbeckii Phil. is a vulnerable species belonging to the terrestrial Bromeliaceae family; it is highly adapted to extremely hyper-arid conditions of the Atacama Desert and Peruvian deserts. In this study, we sequenced, assembled, and annotated its chloroplast genome. T. landbeckii chloroplast genome is 159,131 bp in length, containing a large single-copy region of 87,164 bp, a small single-copy region of 18,521 bp, and a pair of inverted repeat regions of 26,723 bp. The GC content of the chloroplast genome is 37.33%. It encodes a total of 132 genes, including 86 protein-coding genes, 38 tRNA genes and 8 rRNA genes. The phylogenetic tree indicates that T. landbeckii is placed within the Bromeliaceae family and has a close relationship with T. marconae with 100% support., Competing Interests: No potential conflict of interest was reported by the authors., (© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Late embryogenesis abundant (LEA) proteins are a large protein family that mainly function in protecting cells from abiotic stress, but these proteins are also involved in regulating plant growth and development. In this study, we performed a functional analysis of LEA13 and LEA30 from Arabidopsis thaliana . The results showed that the expression of both genes increased when plants were subjected to drought-stressed conditions. The insertional lines lea13 and lea30 were identified for each gene, and both had a T-DNA element in the regulatory region, which caused the genes to be downregulated. Moreover, lea13 and lea30 were more sensitive to drought stress due to their higher transpiration and stomatal spacing. Microarray analysis of the lea13 background showed that genes involved in hormone signaling, stomatal development, and abiotic stress responses were misregulated. Our results showed that LEA proteins are involved in drought tolerance and participate in stomatal density.

Tillandsia marconae Till & Vitek (Bromeliaceae) is a rare plant native species that grows over sand, in the coastal desert from Perú and Chile and is considered an endangered species. In this study, we assembled its chloroplast genome. The draft chloroplast genome of T. marconae is ca . 158,873 bp in length, containing a large single-copy region of 86,937 bp, a small single-copy region of 18,506 bp, and a pair of inverted repeat regions of 26,715 bp. The GC content of the draft chloroplast genome is 37.4%. It encodes a total of 135 genes, including 86 protein-coding genes, 38 tRNA genes, 8 rRNA genes, and three pseudogenes. The phylogenetic tree indicated that T. marconae is placed within the Bromeliaceae family and a close relationship with Tillandsia usneoides with 100% support., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Oregano from Socoroma (Atacama Desert) is characterized by its unique organoleptic properties and distinctive flavor and it is produced using ancestral pesticide-free agricultural practices performed by the Aymara communities. The cultivation in this zone is carried out under extreme conditions where the standard production of different crops is limited by several environmental factors, including aridity, high concentration of salts, and boron among others. However, oregano plants are associated with microorganisms that mitigate biotic and abiotic stresses present in this site. In this work, the S57 strain (member of the Pseudomonas genus that is closely related to Pseudomonas lini ) was isolated from roots of oregano plants, which are grown in soils with high content of non-sodium salts and aluminum. This bacterium stimulates the growth of Micro-Tom tomato plants irrigated with saline-boric water. Moreover, it controls the growth of phytopathogenic fungi Fusarium oxysporum and Botrytis   cinerea and the nematode Meloidogyne incognita under saline-boric conditions. Together with the high levels of bacterial biomass (~47 g/L), these results allow the establishment of the bases for developing a potential new agricultural bioproduct useful for arid and semiarid environments where commercial biological products show erratic behavior.

The southwestern Andes of Peru harbor a hidden taxonomic diversity of reptiles. We describe a new species of Liolaemus Wiegmann (Iguania: Liolaemidae) from xerophytic environments of the southwestern slopes of the Andes of Peru, 2,400-2,900 m asl. The new species, previously considered to be a population of L. insolitus Cei, exhibits unique diagnostic characters of morphology, scalation and color pattern, and molecular evidence that suggest that it belongs in the Liolaemus montanus species group and the L. reichei clade. Moreover, the species is endemic to the eastern slopes of La Caldera batholith in the Department of Arequipa, southern Peru. We also provide information on the conservation status of the species and suggest it be included in the IUCN red list of the threatened species as endangered (EN). A key for the species of the L. reichei clade is provided.

Angelabella (Lepidoptera: Gracillariidae: Oecophyllembiinae) is considered a monotypic Neotropical genus of leaf miner micromoths known only from a few valleys of the arid environments of the Peru-Chile desert, particularly the southernmost part of Peru and northernmost part of Chile (type locality), where natural populations of its primary host plant occur. The geographic distribution of potential host plants provides a scenario for a wider range for this micromoth genus. The aims of this study were to explore the geographic range of Angelabella , determine the spatial distribution of mitochondrial lineages, and test lineage conspecificity hypotheses. The spatial distribution of genetic diversity indicated the presence of four spatial clusters, three of which are north of the previously known geographic range. Genetic distances were 0.2-0.8% and 3.6-8.3% (K2P) between haplotypes of the same and different spatial clusters, respectively. Phylogenetic relationships indicated reciprocal monophyly among the four spatial clusters, suggesting that allopatric differentiation processes have governed the recent history of Angelabella in these arid environments. These groups were defined as different species by four species delimitation methods, suggesting that Angelabella is not a monotypic genus, but harbors at least four morphologically cryptic allopatric species with restricted geographic ranges, including the type species and three candidate species.

Morphology and DNA barcode sequences were used to assess the taxonomic status of a micro-moth of the genus Ithome Chambers, 1875 (Lepidoptera, Cosmopterigidae, Chrysopeleiinae), whose larvae feed on inflorescences of Prosopis tamarugo Phil. (Fabaceae), a tree native to the Pampa del Tamarugal, Atacama Desert, northern Chile. As a result, Ithome tamarugensis Vargas, sp. nov. is described and illustrated. Its genitalia are remarkably similar to those of Ithome tiaynai Vargas, 2004 from coastal valleys of the Atacama Desert. However, the two species can be recognized by the shape of the phallus in males and the shape of the antrum and ductus bursae in females. The genetic distance between DNA barcodes of I. tamarugensis and I. tiaynai was 3.0-3.3% (K2P), and a maximum likelihood analysis indicated that they are in reciprocally monophyletic clusters, providing additional support for the heterospecific status suggested by morphology., (Sebastián Espinoza-Donoso, Dante Bobadilla, Wilson Huanca-Mamani, Marcelo Vargas-Ortiz, Héctor A. Vargas.)

Analysis of maternally inherited genes is especially helpful in population studies of host-specialized insects, as female dispersal is key to find an adequate host plant to ensure larval survival. Bucculatrix mirnae (Lepidoptera: Bucculatricidae) is a little-known Neotropical micromoth native to the arid environments of northern Chile whose hypermetamorphic larvae are miners and skeletonizers on leaves of two species of Baccharis (Asteraceae) shrubs. This micromoth has been detected in three isolated locations embracing a narrow geographic range: two from the coastal valleys of the Atacama Desert near sea level and one from the western slopes of the Andes at about 3000 m elevation. As the dispersal of B. mirnae is mostly restricted to the small adult stage, the altitudinal gradient and desert areas among the three localities could be effective barriers, triggering genetic differentiation among populations. Sequences of the DNA barcode fragment of the cytocrome oxidase subunit I mitochondrial gene were analyzed to assess for the first time the patterns of genetic variation of B. mirnae. Fifteen haplotypes, each exclusive to one locality, were found in the 71 specimens analyzed. Genetic divergence (K2P) between haplotypes of different localities was at least 2.0%. A Bayesian analysis with sequences of congeneric species grouped all the B. mirnae haplotypes in a clade, in which three well-supported locality-specific haplogroups were found. In concordance with this pattern, an analysis of molecular variance showed that the highest genetic variation was found among populations. Furthermore, all the population pairwise comparisons (F ST ) were significant. These results suggest that female migration between isolated populations of B. mirnae is absent. This pattern must be considered in the current scenario of habitat destruction and modification in the arid environments of northern Chile.

Long non-coding RNAs (lncRNAs) have been defined as transcripts longer than 200 nucleotides, which lack significant protein coding potential and possess critical roles in diverse cellular processes. Long non-coding RNAs have recently been functionally characterized in plant stress-response mechanisms. In the present study, we perform a comprehensive identification of lncRNAs in response to combined stress induced by salinity and excess of boron in the Lluteño maize, a tolerant maize landrace from Atacama Desert, Chile. We use deep RNA sequencing to identify a set of 48,345 different lncRNAs, of which 28,012 (58.1%) are conserved with other maize (B73, Mo17 or Palomero), with the remaining 41.9% belonging to potentially Lluteño exclusive lncRNA transcripts. According to B73 maize reference genome sequence, most Lluteño lncRNAs correspond to intergenic transcripts. Interestingly, Lluteño lncRNAs presents an unusual overall higher expression compared to protein coding genes under exposure to stressed conditions. In total, we identified 1710 putatively responsive to the combined stressed conditions of salt and boron exposure. We also identified a set of 848 stress responsive potential trans natural antisense transcripts ( trans -NAT) lncRNAs, which seems to be regulating genes associated with regulation of transcription, response to stress, response to abiotic stimulus and participating of the nicotianamine metabolic process. Reverse transcription-quantitative PCR (RT-qPCR) experiments were performed in a subset of lncRNAs, validating their existence and expression patterns. Our results suggest that a diverse set of maize lncRNAs from leaves and roots is responsive to combined salt and boron stress, being the first effort to identify lncRNAs from a maize landrace adapted to extreme conditions such as the Atacama Desert. The information generated is a starting point to understand the genomic adaptabilities suffered by this maize to surpass this extremely stressed environment., Competing Interests: The authors declare no conflict of interest. The funding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

To investigate the genetic and molecular regulation that the female gametophyte could exert over neighboring sporophytic regions of the ovule, we performed a quantitative comparison of global expression in wild-type and nozzle/sporocyteless (spl) ovules of Arabidopsis thaliana (Arabidopsis), using Massively Parallel Signature Sequencing (MPSS). This comparison resulted in 1517 genes showing at least 3-fold increased expression in ovules lacking a female gametophyte, including those encoding 89 transcription factors, 50 kinases, 25 proteins containing a RNA-recognition motif (RRM), and 20 WD40 repeat proteins. We confirmed that eleven of these genes are either preferentially expressed or exclusive of spl ovules lacking a female gametophyte as compared to wild-type, and showed that six are also upregulated in determinant infertile1 (dif1), a meiotic mutant affected in a REC8-like cohesin that is also devoided of female gametophytes. The sporophytic misexpression of IOREMPTE, a WD40/transducin repeat gene that is preferentially expressed in the L1 layer of spl ovules, caused the arrest of female gametogenesis after differentiation of a functional megaspore. Our results show that in Arabidopsis, the sporophytic-gametophytic cross talk includes a negative regulation of the female gametophyte over specific genes that are detrimental for its growth and development, demonstrating its potential to exert a repressive control over neighboring regions in the ovule.

Chromatin-remodeling factors regulate the establishment of transcriptional programs during plant development. Although 42 genes encoding members of the SWI2/SNF2 family have been identified in Arabidopsis thaliana, <10 have been assigned a precise function on the basis of a mutant phenotype, and none have been shown to play a specific role during the gametophytic phase of the plant life cycle. A. thaliana chromatin-remodeling protein 11 (CHR11) encodes an imitation of switch (ISWI)-like chromatin-remodeling protein abundantly expressed during female gametogenesis and embryogenesis in Arabidopsis. To determine the function of CHR11 in wild-type plants, we introduced a hairpin construct leading to the production of double-stranded RNA, which specifically degraded the endogenous CHR11 mRNA by RNA interference (RNAi). Transcription of the RNAi-inducing hairpin RNA was driven by either a constitutive cauliflower mosaic virus 35S promoter (CaMV35S) acting at most stages of the sporophytic phase or a newly identified specific promoter acting at the onset of the female gametophytic phase (pFM1). All adult transformants that constitutively lacked sporophytic CHR11 activity showed reduced plant height and small cotyledonary embryos with limited cell expansion. In contrast, RNAi lines in which CHR11 was specifically silenced at the onset of female gametogenesis (megagametogenesis) had normal height and embryo size but had defective female gametophytes arrested before the completion of the mitotic haploid nuclear divisions. These results show that CHR11 is essential for haploid nuclear proliferation during megagametogenesis and cell expansion during the sporophytic phase, demonstrating the functional versatility of SWI2/SNF2 chromatin-remodeling factors during both generations of the plant life cycle.

Genomic imprinting is a mitotically stable epigenetic modification that results in the functional non-equivalency of both parental genomes following fertilization. In flowering plants, studies of parent-of-origin effects have mostly identified genes that are only transcribed from a maternally inherited allele. In Arabidopsis, the Polycomb group protein MEDEA regulates seed development through the expression of the MADS-box gene PHERES1. Activation of the maternal MEDEA allele requires the function of DEMETER, a plant DNA glycosylase that also controls the transcriptional activity of the maternally inherited allele of the late-flowering gene FWA. Current studies of parent-of-origin effects have mostly identified genes that are only transcribed from a maternally inherited allele. Our current understanding of parent-of-origin effects could represent a new form of an Oedipus complex in which flowering plants prefer to rely transcriptionally on their maternal rather than their paternal chromosomes to ensure normal initiation of seed development.