Phytolith evidence for the pastoral origins of multi-cropping in Mesopotamia (ancient Iraq)

Multi-cropping was vital for provisioning large population centers across ancient Eurasia. In Southwest Asia, multi-cropping, in which grain, fodder, or forage could be reliably cultivated during dry summer months, only became possible with the translocation of summer grains, like millet, from Africa and East Asia. Despite some textual sources suggesting millet cultivation as early as the third millennium BCE, the absence of robust archaeobotanical evidence for millet in semi-arid Mesopotamia (ancient Iraq) has led most archaeologists to conclude that millet was only grown in the region after the mid-first millennium BCE introduction of massive, state-sponsored irrigation systems. Here, we present the earliest micro-botanical evidence of the summer grain broomcorn millet (Panicum miliaceum) in Mesopotamia, identified using phytoliths in dung-rich sediments from Khani Masi, a mid-second millennium BCE site located in northern Iraq. Taphonomic factors associated with the region’s agro-pastoral systems have likely made millet challenging to recognize using conventional macrobotanical analyses, and millet may therefore have been more widespread and cultivated much earlier in Mesopotamia than is currently recognized. The evidence for pastoral-related multi-cropping in Bronze Age Mesopotamia provides an antecedent to first millennium BCE agricultural intensification and ties Mesopotamia into our rapidly evolving understanding of early Eurasian food globalization.

The Life Cycle and Ultrastructure of the Host Response of the Smut Pathogen, Anthracocystis destruens, on Broomcorn Millet

Broomcorn millet smut caused by the fungus Anthracocystis destruens is one of the most destructive diseases in broomcorn millet production. The life cycle of A. destruens and host defense responses against A. destruens remain elusive. Here we investigated the disease symptom development and the parasitic process of A. destruens as well as the ultrastructure of the host-pathogen interface. The results showed that there are four typical symptoms of broomcorn millet smut, which are blackfly, cluster leaves, hedgehog head and incomplete fruiting. A. destruens colonizes all tissues of broomcorn millet but only produces teliospores in the inflorescence. After infection, A. destruens proliferates in the host likely in a systemic manner. Ultrastructural study of the infected inflorescence showed that the pathogen grows intercellularly and intracellular within the host. The host active defense response against pathogen invasion, includes host secrets callose analogs and highly electron-dense deposits to prevent pathogen infection.

Genomic resources of broomcorn millet: demonstration and application of a high-throughput BAC mapping pipeline

Background With high-efficient water-use and drought tolerance, broomcorn millet has emerged as a candidate for food security. To promote its research process for molecular breeding and functional research, a comprehensive genome resource is of great importance. Results Herein, we constructed a BAC library for broomcorn millet, generated BAC end sequences based on the clone-array pooled shotgun sequencing strategy and Illumina sequencing technology, and integrated BAC clones into genome by a novel pipeline for BAC end profiling. The BAC library consisted of 76,023 clones with an average insert length of 123.48 Kb, covering about 9.9-fold of the 850 Mb genome. Of 9216 clones tested using our pipeline, 8262 clones were mapped on the broomcorn millet cultivar longmi4 genome. These mapped clones covered 308 of the 829 gaps left by the genome. To our knowledge, this is the only BAC resource for broomcorn millet. Conclusions We constructed a high-quality BAC libraray for broomcorn millet and designed a novel pipeline for BAC end profiling. BAC clones can be browsed and obtained from our website (http://eightstarsbio.com/gresource/JBrowse-1.16.5/index.html). The high-quality BAC clones mapped on genome in this study will provide a powerful genomic resource for genome gap filling, complex segment sequencing, FISH, functional research and genetic engineering of broomcorn millet.

Plant remains unearthed at the Donghulin site in Beijing: discussion on results of flotation

A number of charred plant seeds were recovered from the Donghulin site by means of flotation. The site is located in suburban Beijing and dates from 11,000 to 9000 BP. A total of 14 charred grains of foxtail millet have been collected and identified as of the domesticated species (Setaria italica) according to morphological analysis. One grain of broomcorn millet was also identified. These are the earliest domesticated millet grains recovered by flotation, providing crucial archaeological evidence for understanding the timing, locations, and processes of millet domestication. Moreover, the charred seeds of Setaria viridis provide important clues for exploring the wild ancestral plants of foxtail millet and the domestication process. The results of flotation at the Donghulin site are important for understanding the origins of dryland agriculture in North China, which was predominated by millet farming.

Recovery of Chloroplast Genomes from Medieval Millet Grains Excavated from the Areni-1 Cave in Southern Armenia

Broomcorn millet (Panicum miliaceum L.) was domesticated in northern China at least 7,000 years ago and was subsequentially adopted as a cereal in many areas throughout Eurasia. One such locale is Areni-1 an archaeological cave site in Southern Armenia, a region that has an important history in crop domestication. The rich botanical material found at Areni-1 includes grains identified by morphology as broomcorn millet that were 14C dated to the medieval era (873 ± 36 CE and 1118 ± 35 CE). To retrace the demographic history of these broomcorn millet samples, we used ancient DNA extraction and hybridization capture enrichment to sequence and assemble three chloroplast genomes from the Areni-1 grains and then compared these sequences to 50 modern chloroplast genomes. Overall, the chloroplast genomes contained a low amount of diversity and little inference on broomcorn demography could be made. However, in a phylogeny the chloroplast genomes separated into two clades with strong bootstrap support, similar to what has been reported for nuclear DNA from broomcorn millet. In a haplotype network, the chloroplast genomes of two accessions of wild (undomesticated) broomcorn millet contained a relatively large number of variants, 11 SNPs. These SNPs were not present in the domesticated varieties, suggesting these wild accessions may not be directly related to the lineages that underwent domestication or that broomcorn millet may have undergone a domestication bottleneck resulting in lost diversity in the chloroplast genome. These results demonstrate that broomcorn millet from archaeological sites can preserve DNA for at least 1000 years and serve as a genetic resource to study the domestication of this cereal crop.

Food, farming and trade on the Danube frontier: plant remains from Roman Aelia Mursa (Osijek, Croatia)

Archaeobotanical investigations at the Roman town of Aelia Mursa, located near the Danube frontier in modern day Croatia, have revealed an extraordinary assemblage of food remains from a series of pits dated to the early 2nd century ad. The site yielded a wide array of economically important food remains, including staples such as Hordeum (barley), Panicum miliaceum (broomcorn millet), Triticum aestivum (bread wheat), Secale cereale (rye), Lens culinaris (lentil) and Vicia faba (broad bean). We also found a range of fruits, nuts, herbs and vegetables, such as Daucus carota (carrot), Cichorium intybus (chicory), Allium sativum (garlic), Ficus carica (fig), Vitis vinifera (grape) and Olea europaea (olive). Further, we found clearly identifiable remains of eggshell, fish bones and scales, unidentifiable fruit flesh and porridge or bread remains, as well as possible animal dung. The site provides important evidence of exotic foods including Piper nigrum (pepper), Oryza sp. (rice) and Punica granatum (pomegranate). This diverse and unique assemblage provides a tantalising insight into the character of food, farming and trade of the people living on the frontier of the Roman Empire.