CADMIUM EXCLUSION FROM RICE GRAINS:DEVELOPMENT OF MOLECULAR AND PHYSIOLOGICAL MARKERS

Among trace elements not essential for plant growth and metabolism, Cd is of particular concern as it may exert phytotoxic effects and have direct consequences on human health by accumulating in staple food crops which make up a large proportion of dietary intake. Cd is generally present in the soil medium either naturally and/or from anthropogenic sources. Concerning agricultural activities, the application of sewage sludge and phosphate fertilizers containing Cd as an impurity, as well as the use of Cd containing irrigation water, are of particular relevance. Compared to other heavy metals, Cd constitutes a big issue in terms of food safety as it tends to be more mobile and thus more available to be translocated to the edible portion of the plant, causing acute or chronic toxicity to humans even at low soil concentrations. The well established tendency of rice (Oryza sativa L.) to accumulate Cd to levels often exceeding the international limits for the cereal grain trade highlights the need to apply sound strategies aimed at reducing the risk of grain Cd accumulation. Compared to the sole use of agronomic techniques, the selection of rice cultivars that accumulate low Cd in the grains by taking advantage from the broad variability in the Cd accumulation trait observed in Indica and Japonica cultivars is far more promising. Therefore, the general purpose of this study was to deepen the knowledge of the physiological basis governing Cd distribution in rice, with particular concern on Cd root retention and Cd translocation, as they have been seen to be crucial in determining Cd accumulation. Specifically, the role of phytochelatins (PCs) in chelation and subcellular compartimentalization of Cd in the roots was investigated, both by characterizing Cd-PCs complexes with respect of the external Cd concentration and examining the molecular basis of their synthesis. As Cd chelation by PCs has seen to be a crucial but not the only determinant in limiting the amount of Cd potentially available to be translocated to the shoots, the focus moved on the identification of the genes encoding transporters putatively involved in Cd xylem loading. Particularly we looked at two transporters, OsHMA2 and OsHMA4, belonging to the P1B-type ATPase subfamily, acknowledging the major role of such class of transporters in Cd translocation. While characterizing these transporters both by molecular and physiological analysis, the occurrence of clear competition effects of Cd over Zn at the translocation level emerged. Such an outcome highlighted that Cd movement determining its allocation through the plant is not strictly associated to Zn, which is likely to result from the existence of Cd transport pathways that are Zn-independent. These results, obtained by exposing rice plants to relatively low Cd concentrations aiming at simulating the real conditions in moderately contaminated soils, contributed to advance the understanding of the complex network of processes governing Cd accumulation in rice grains which, despite the economical and agricultural relevance of this crop, is still lacking. With regard to this, our study could be intended as a step further towards the development of molecular and/or physiological markers to early select rice genotypes able to exclude Cd from the grains with the intent of ensuring the food safety of the consumers

Cashew, from seed to market : a review

Cashew is a tropical tree native to South America. Cashew was introduced in Asia and Africa by European explorers in the sixteenth century. The world production of cashew raw nuts reached 4.27 million tons in 2011. Vietnam is the top producer of raw nuts, and India is the first processor and exporter of processed nuts. The cashew market is expected to remain strong due to the high growth of production in some areas such as West Africa. For instance, a 40\ua0% production increase has been observed in Nigeria over the last 5\ua0years. There is also an increasing exploitation of high-value by-products, particularly those made of cashew nut shell liquid. Cashew production is potentially a major value for smallholder farmers from emerging countries. Despite the relevance of cashew production on the international markets and the potential for boosting rural development and reducing poverty, a complete review on cashew is missing. Therefore, we review here the cashew production chain. Our main conclusions are as follows: (1) several management practices, processing methods, and uses of products and by-products are published; (2) however, there is still a lack of knowledge due to a scattered research framework lacking integrated research programs; (3) smallholder farmers face major constraints limiting the development of cashew sector locally, ranging from difficult access to good planting material and training to lack of investment for innovating processing facilities; (4) among them, women, that account for up to 95\ua0% of the workforce in the sector, receive lower wages and are subject to worse working conditions

The Environmental and Social Impact Assessment : a further step towards an integrated assessment process

Since its introduction, the Environmental Impact Assessment (EIA) process has been subject to both critiques and adjustments with the aim of addressing the main issues emerging from its wide implementation. In this regard, one of the most active debates has focused on the weight allocated to the analysis of the social impacts of project implementation, often considered too limited. The Social Impact Assessment (SIA) was then launched but it has for long been considered as a component subordinate to the Environmental Impact Assessment. As a follow up to such a debate, the Environmental and Social Impact Assessment (ESIA) has been introduced and is now being widely applied by multilateral donors, international agencies and private lending institutions. It appears as a promising tool based on an integrated assessment where biophysical and social impacts of projects, programs and policy initiatives, are equally acknowledged and evaluated. However, it still misses a proper scientific foundation as, to date, few scientific publications on the theoretical base, opportunities and limits of such an assessment process have been made available. Therefore, the present paper aims to catch the attention of the scientific community on this gap in research, as well as to contribute to fill it. With this aim, a wide spectrum of grey literature documents has been analyzed in order to deduce the Environmental and Social Impact Assessment's core elements and advancements potentially provided in the framework of an increased awareness of environmental issues, no longer limited to biophysical components. While retracing the Environmental Impact Assessment (EIA) and Social Impact Assessment (SIA) co-evolution over time, as well as the outset of the Environmental and Social Impact Assessment (ESIA), a profound change in the approach to environmental and social concerns arising from project implementation clearly emerged. Such a change, that occurred with a particular emphasis since the early 2000s, has led to the establishment of the Environmental and Social Impact Assessment as an integrated assessment process properly capturing the interrelationship between land and society

Cadmium exclusion from rice grains : development of molecular and physiological markers

Cd accumulation in rice shoots and grains depends on its uptake by roots, xylem-loading-mediated translocation to shoots, and further translocation to grains via the phloem. Here we present a preliminary characterizations of rice genes involved in these processes: PCS1 and PCS2, coding for two isoforms of phytochelatin synthase, and HMA2 and HMA4, belonging to the P1B-Type ATPase heavy metal transporter family