RESUMO
BACKGROUND AND SCOPE: Agaves played a central role as multi-use plants providing food, fibre and beverage to pre-contact and historical Mesoamerican cultures. However, their importance to Indigenous Peoples in the Southwest USA and northern Mexico, where they occur because of adaptations such as CAM photosynthesis, is less well known. Archaeological research indicates the Hohokam and other pre-contact Southwestern agrarian people increased agricultural potential in this region by engineering riverine terraces and bajadas for agave dry farming. Agricultural features such as terraces and rock piles were especially characteristic of post-1000 CE with the increase of dense, aggregated populations. We present an overview of six pre-contact agave domesticates (PCADs) the Hohokam and other cultures cultivated, and their ecological and cultural attributes. These PCADs are Agave murpheyi, A. delamateri, A. phillipsiana, A. sanpedroensis, A. verdensis and A. yavapaiensis. CONCLUSION: Pre-contact agriculturists cultivated at least six once cryptic domesticated agave species in the modern Arizona landscape associated with pre-contact agricultural features, such as rock structures. Because of the longevity and primarily asexual reproduction of these agaves, relict clones have persisted to the present day, providing an opportunity to study pre-contact nutrition, trade, migration and agricultural practices. Taxonomic data imply that pre-contact farmers selected desirable attributes, initiating domestication processes that resulted in discrete lineages. These agaves are morphologically and genetically distinct from Southwest US and northern Mexico wild agaves and Mesoamerican wild and domesticated species. Additionally, the remnant clones present a rare opportunity to examine domesticates virtually unchanged since they were last cultivated prehistorically. These discoveries underline the need to view landscapes and some plant species from a cultural, rather than 'natural', perspective and discern potential cryptic species veiled by traditional taxonomic treatments. Protecting and understanding the distribution, and ecological and cultural roles of these plants require interdisciplinary collaboration between botanists, archaeologists, federal agencies and Indigenous Peoples.
Assuntos
Agave , Humanos , Agave/anatomia & histologia , Arizona , Domesticação , Agricultura , MéxicoRESUMO
Cactaceae comprise a diverse and iconic group of flowering plants which are almost exclusively indigenous to the New World. The wide variety of growth forms found amongst the cacti have led to the trafficking of many species throughout the world as ornamentals. Despite the evolution and physiological properties of these plants having been extensively studied, little research has focused on cactus-associated viral communities. While only single-stranded RNA viruses had ever been reported in cacti, here we report the discovery of cactus-infecting single-stranded DNA viruses. These viruses all apparently belong to a single divergent species of the family Geminiviridae and have been tentatively named Opuntia virus 1 (OpV1). A total of 79 apparently complete OpV1 genomes were recovered from 31 different cactus plants (belonging to 20 different cactus species from both the Cactoideae and Opuntioideae clades) and from nine cactus-feeding cochineal insects (Dactylopius sp.) sampled in the USA and Mexico. These 79 OpV1 genomes all share > 78.4% nucleotide identity with one another and < 64.9% identity with previously characterized geminiviruses. Collectively, the OpV1 genomes display evidence of frequent recombination, with some genomes displaying up to five recombinant regions. In one case, recombinant regions span ~40% of the genome. We demonstrate that an infectious clone of an OpV1 genome can replicate in Nicotiana benthamiana and Opuntia microdasys. In addition to expanding the inventory of viruses that are known to infect cacti, the OpV1 group is so distantly related to other known geminiviruses that it likely represents a new geminivirus genus. It remains to be determined whether, like its cactus hosts, its geographical distribution spans the globe.