The (seco)iridoids and their derivatives, the monoterpenoid indole alkaloids (MIAs), form two large families of plant-derived bioactive compounds with a wide spectrum of high-value pharmacological and insect-repellent activities. Vinblastine and vincristine, MIAs used as anticancer drugs, are produced by Catharanthus roseus in extremely low levels, leading to high market prices and poor availability. Their biotechnological production is hampered by the fragmentary knowledge of their biosynthesis. Here we report the discovery of the last four missing steps of the (seco)iridoid biosynthesis pathway. Expression of the eight genes encoding this pathway, together with two genes boosting precursor formation and two downstream alkaloid biosynthesis genes, in an alternative plant host, allows the heterologous production of the complex MIA strictosidine. This confirms the functionality of all enzymes of the pathway and highlights their utility for synthetic biology programmes towards a sustainable biotechnological production of valuable (seco)iridoids and alkaloids with pharmaceutical and agricultural applications.

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SummaryArtemisia annua, which produces the anti-malaria compound artemisinin, occurs as highartemisinin production (HAP) and low-artemisinin production (LAP) chemotypes. Understanding the basis of the difference between these chemotypes would assist breeding and optimising artemisinin biosynthesis.Here we present a systematic comparison of artemisinin biosynthesis genes that may be involved in determining the chemotype (CYP71AV1, DBR2 and ALDH1). These genes were isolated from the two chemotypes and characterized using transient expression in planta. The enzyme activity of DBR2 and ALDH1 from the two chemotypes did not differ, but structural differences in CYP71AV1 from LAP and HAP chemotypes (AMOLAP and AMOHAP, respectively) resulted in altered enzyme activity.AMOLAP displays a seven amino acids N-terminal extension compared with AMOHAP. The GFP fusion of both proteins show equal localization to the ER but AMOHAP may have reduced stability.Upon transient expression in Nicotiana benthamiana, AMOLAP displayed a higher enzyme activity than AMOHAP. However, expression in combination with the other pathway genes also resulted in a qualitatively different product profile ('chemotype'); that is, in a shift in the ratio between the unsaturated and saturated (dihydro) branch of the pathway.

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Oil palm has become an important source of revenue for smallholders in Indonesia, but productivity of smallholder plantations is generally poor. Nutrient limitations have been suggested as an important agronomic constraint to yield. Our research aimed to quantify fertiliser use, soil and tissue nutrient status, and palm growth and yield in a sample of independent smallholder plantations. We selected 49 plantations in Indonesia in two provinces with contrasting soils. For all plantations, we obtained self-reported fertiliser use and yield data, collected soil and tissue samples, and analysed vegetative growth. More than 170 kg N ha −1 year −1 was applied in one site, and P was applied in excess of recommended quantities in both sites, but on average farmers applied less than 100 kg K ha −1 year −1 . Soils in the palm circle were poor in N, P and K in 29, 40 and 82% of the plantations, and deficiencies were measured in 57, 61 and 80% of the leaflet samples, respectively. We found statistically significant correlations between tissue nutrient concentrations and vegetative growth, but a large part of the variation in the data remained unaccounted for. Single leaf area was reduced in >80% of the plantations. Average yields were estimated to be 50-70% of the water-limited potential. Our results demonstrate that widespread nutrient imbalances and deficiencies, especially potassium and phosphorus, occur in smallholder oil palm plantations, due to inadequate and unbalanced fertiliser application practices. These deficiencies may be an important underlying cause of the overall poor productivity, which threatens the economic and environmental sustainability of the smallholder sector.

In Indonesia more than 40% of the area under oil palm is owned by smallholders. The productivity in smallholder plantations is usually less than in large plantations, and limited fertiliser applications may be one of the key reasons. We investigated the use of fertilisers by [ 300 smallholder farmers in Sumatra and Kalimantan, some of whom were involved in training programmes aimed at yield improvement. In our sample, the total applications of N were largest (166 kg ha-1 year-1), followed by K (122 kg) and P (56 kg). The applications of K were insufficient to compensate for the off-take with a production of 20 tonne fruit bunches ha-1 year-1 , while N applications were excessive. On average, farmers applied 1130 kg fertiliser ha-1 year-1 , and relied strongly on subsidised fertilisers, especially NPK Ponska (66%) and urea (39%). The average costs for fertiliser application were USD 225 ha-1 year-1. Trained farmers applied significantly more P in one research area, but for the other nutrients and research areas, there was no significant difference between trained and untrained farmers. Plantation size and nutrient application were weakly correlated in some areas, but not in the sample as a whole. Previously reported nutrient application rates were mostly less than our findings indicated, suggesting that actual nutrient limitations may be more severe. To overcome nutrient limitations and enhance nutrient use efficiency, we recommend that fertilisers are used in the correct balance; a ground cover vegetation is maintained to protect against erosion; and the application of empty fruit bunches is encouraged.

ABSTRACT. Common lands provide smallholder farmers in Africa with firewood, timber, and feed for livestock, and they are used to complement human diets through the collection of edible nontimber forest products (NTFPs). Farmers have developed coping mechanisms, which they deploy at times of climatic shocks. We aimed to analyze the importance of NTFPs in times of drought and to identify options that could increase the capacity to adapt to climate change. We used participatory techniques, livelihood analysis, observations, and measurements to quantify the use of NTFPs. Communities recognized NTFPs as a mechanism to cope with crop failure. We estimated that indigenous fruits contributed to approximately 20% of the energy intake of wealthier farmers and to approximately 40% of the energy intake of poor farmers in years of inadequate rainfall. Farmers needed to invest a considerable share of their time to collect wild fruits from deforested areas. They recognized that the effectiveness of NTFPs as an adaptation option had become threatened by severe deforestation and by illegal harvesting of fruits by urban traders. Farmers indicated the need to plan future land use to (1) intensify crop production, (2) cultivate trees for firewood, (3) keep orchards of indigenous fruit trees, and (4) improve the quality of grazing lands. Farmers were willing to cultivate trees and to organize communal conservation of indigenous fruits trees. Through participatory exercises, farmers elaborated maps, which were used during land use discussions. The process led to prioritization of pressing land use problems and identification of the support needed: fast-growing trees for firewood, inputs for crop production, knowledge on the cultivation of indigenous fruit trees, and clear regulations and compliance with rules for extraction of NTFPs. Important issues that remain to be addressed are best practices for regeneration and conservation, access rules and implementation, and the understanding and management of competing claims on the common lands. Well-managed communal resources can provide a strong tool to maintain and increase the rural communities' ability to cope with an increasingly variable climate.

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