Plant-parasitic nematodes are costly burdens of crop production. Ubiquitous in nature, phytoparasitic nematodes are associated with nearly every important agricultural crop and represent a signiicant constraint on global food security. Root-knot nematodes (Meloidogyne spp.) cyst nematodes (Heterodera and Globodera spp.) and lesion nematodes (Pratylenchus spp.) rank at the top of list of the most economically and scientiically important species due to their intricate relationship with the host plants, wide host range, and the level of damage ensued by infection. Limitations on the use of chemical pesticides have brought increasing interest in studies on alternative methods of nematode control. Among these strategies of nonchemical nematode management is the identiication and implementation of host resistance. In addition, nematode genes involved in parasitism represent key targets for the development of control through gene silencing methods such as RNA interference. Recently, transcriptome proiling analyses has been used to distinguish nematode resistant and susceptible genotypes and identify the speciic molecular components and pathways triggered during the plant immune response to nematode invasion. This summary highlights the importance of plant-parasitic nematodes in agriculture and the molecular events involved in plant-nematode interactions.

The Sustainable Technology for Orange and Purple Sweetpotatoes (STOPS) project, led by researchers from Tuskegee University, USA, identified gaps in the value chain from production, processing, product development to consumption of sweet potato, aimed at addressing vitamin A deficiency (VAD) and improving the health and nutritional status of vulnerable populations in rural communities in Ghana. The orange sweet potato (OSP) could be an inexpensive, year-round, rich source of β-carotene, a precursor of vitamin A. The anthocyanins that account for the purple pigmentation in the purple variety are powerful antioxidants with good bioavailability to be easily absorbed by the body. The STOPS project promotes the utilization of both varieties into value-added products from the root including flour, yogurt, and bread. Sweet potato-based bread, TUO vitabread, prepared from a composited wheat flour and OSP puree at a ratio of 2.5:1 ("as-is" basis) was compared with traditional wheat (white) bread on the Ghanaian market in compositional and sensory analyses. The proximate composition (moisture, protein, fat, ash and carbohydrate by difference) and energy content were not statistically different (P>0.05), although TUO vitabread contains 18% more moisture than the white bread. The β-carotene and lutein concentrations in the OSP-based bread were approximately 6-fold higher (P=0.01). The TUO vitabread could meet 17% of the daily adequate intake of vitamin A for a 1-to 3-year-old child consuming about 50 g of the bread, but only 3% from the white bread. Consumer preference assessment of 50 undergraduate students showed a high preference for the OSP puree-based bread but further work on extension of shelf-life under ambient conditions is warranted. Thus, the inclusion of OSP in the traditional diet can be an inexpensive and year-round source of dietary β-carotene to complement the vitamin A supplementation programme to reduce VAD in children.

Peanut plants (Arachis hypogaea L. cv. Georgia Red) were grown hydroponically using a recirculating nutrient film technique. The effect of CO2 enrichment on nutritive composition of hydroponic peanut seeds was examined at two elevated CO2 levels (700 and 1400 ppm) that simulate potential conditions in National Aeronautics and Space Administration (NASA) Controlled Ecological Life-Support Systems (CELSS) and compared to ambient CO2 condition in hydroponics (the control). Plants were harvested at 97 days after planting, and the seeds were air-dried and analyzed for composition. Percentages of crude protein, crude fat, ash, and carbohydrate of hydroponic peanut seeds were around 30%, 30%, 3%, and 30%, respectively. The major amino acids were aspartic acid, glutamic acid, and arginine. The limiting amino acid of peanut, methionine, was 1.2%. Linoleic acid was the major fatty acid, followed by oleic and palmitic acids. The major mineral elements were K, P, Mg, and Ca. The results showed that certain peanut varieties can be grown hydroponically. The composition of the hydroponically grown peanuts is generally similar to reported peanut composition. The nutrient composition was not affected at the elevated CO2 concentrations investigated. Keywords: CELSS; hydroponic; NFT; elevated CO2 levels; peanut

Because sweetpotato [Ipomoea batatas (L.) Lam.] stem cuttings regenerate very easily and quickly, a study of their early growth and development in microgravity could be useful to an understanding of morphological changes that might occur under such conditions for crops that are propagated vegetatively. An experiment was conducted aboard a U.S. Space Shuttle to investigate the impact of microgravity on root growth, distribution of amyloplasts in the root cells, and on the concentration of soluble sugars and starch in the stems of sweetpotatoes. Twelve stem cuttings of ‘Whatley/Loretan’ sweetpotato (5 cm long) with three to four nodes were grown in each of two plant growth units filled with a nutrient agarose medium impregnated with a half-strength Hoagland solution. One plant growth unit was flown on Space Shuttle Columbia for 5 days, whereas the other remained on the ground as a control. The cuttings were received within 2 h postflight and, along with ground controls, processed in ≈45 min. Adventitious roots were counted, measured, and fixed for electron microscopy and stems frozen for starch and sugar assays. Air samples were collected from the headspace of each plant growth unit for postflight determination of carbon dioxide, oxygen, and ethylene levels. All stem cuttings produced adventitious roots and growth was quite vigorous in both ground-based and flight samples and, except for a slight browning of some root tips in the flight samples, all stem cuttings appeared normal. The roots on the flight cuttings tended to grow in random directions. Also, stem cuttings grown in microgravity had more roots and greater total root length than ground-based controls. Amyloplasts in root cap cells of ground-based controls were evenly sedimented toward one end compared with a more random distribution in the flight samples. The concentration of soluble sugars, glucose, fructose, and sucrose and total starch concentration were all substantially greater in the stems of flight samples than those found in the ground-based samples. Carbon dioxide levels were 50% greater and oxygen marginally lower in the flight plants, whereas ethylene levels were similar and averaged less than 10 nL·L−1. Despite the greater accumulation of carbohydrates in the stems, and greater root growth in the flight cuttings, overall results showed minimal differences in cell development between space flight and ground-based tissues. This suggests that the space flight environment did not adversely impact sweetpotato metabolism and that vegetative cuttings should be an acceptable approach for propagating sweetpotato plants for space applications.

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