Abiotic stress is the major limiting factor of forage crops growth and yields. The objective of this work was to study the stress tolerance and regeneration capability of transgenic forage crops carrying a MsHSP23 gene, encoding a alfalfa mitochondrial sHSP protein. The expression of the MsHSP23 gene was confirmed in bacteria, recombinant mHSP23 conferred tolerance to salinity and arsenic stress. Furthermore, mHSP23 was cloned in a plant expressing vector and transformed into forage crops such as alfalfa, tall fescue and bent grass. The transgenic plants exhibited enhanced tolerance to salinity and arsenic stress conditions. In comparison to wild type plants, transgenic plants were exhibited significantly lower electrolyte leakage. Moreover, the transgenic plants had superior germination rates when placed on medium containing arsenic. Taken together, these overexpression results imply that mHSP23 plays an important role in salinity and arsenic stress tolerance in transgenic forage crops. This approach could be useful to develop stress-tolerant plants including forage crops.

A gene flow has been tested from transgenic herbicide-resistant Chinese cabbage to major crops in Cruciferae. Hybridizations were made between transgenic Basta-resistant Chinese cabbage and non-transgenic Chinese cabbage, B. napus, B. juncea and Brassicoraphanus(B. campestris × Raphanus sativus, 2n=4x=38) with honey-bee mediated fertilization. Progeny populations were selected by Basta herbicide. The F1 hybrids with pat gene were again self-pollinated or cross-pollinated with nontransgenic Chinese cabbage and rape naturally or artificially. Pod setting ratio were compared as a tentative parameter for potential gene flow. Key agronomic characters were compared among the F1 hybrid populations obtained. In the days to flowering after cold treatment, the F1 hybrids of Brassicoraphanus x B. campestris and B. napus x B. campestris(GM) were the shortest (75 days), and the GM Chinese cabbage and the F1 hybrid of B. juncea x B. campestris(GM) were 87 and 93 days, respectively. In the stem length, the F1 hybrid of Brassicoraphanus x B. campestris was the longest(175 cm), and followed by the F1 hybrid of B. napus x B. campestris(GM), the F1 hybrid of B. juncea x B. campestris(GM) in order. The naturally occurring pod setting ratios were fluctuated seriously among individual and segregation lines. Natural pod setting of the transgenic Chinese cabbage was 10 to 19 %. The F1 hybrid of B. napus x B. campestris(GM) showed the ratio of 4-11%. However, the F1 hybrids of B. juncea x B. campestris and Brassicoraphanus x B. campestris(GM) did not produced seeds. The F1 hybrids with pat gene were hybridized with nontransgenic Chinese cabbage and rape by artificial bud pollination to test potential gene flow. All cross combinations except Brassicoraphanus produced seeds and the pod setting ratios ranged from 35 to 100 percentages. Thus, the potentials of the gene flow from Chinese cabbage with pat gene to the order specise in the same gene interspecies or intergeneric species and from the F1 hybrids with pat gene to nontransgenic Chinese cabbage and rape were detected. Herbicide resistant test to the acquired seeds by natural and artificial pollinations including honey-bee mediated fertilization using the same materials is going on.

The dramatic increase in population accompanied by rapid industrialization in developing countries including China has caused imbalances in the supply of food and energy. To cope with these global crises over food and energy supplies as well as environmental problems, it is urgently required to develop industrial GM crops to be grown in marginal lands including desertification and polluted lands for sustainable agriculture. Recently we developed several tansgenic crops such as sweetpotato (Ipomoea batatas L. Lam), potato (Solanum tuberosum L.), tall fescue (Festuca arundinacea Schreb.) expressing genes of both Cu/Zn superoxide dismutase and ascorbate peroxidase in the chloroplasts under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter (referred to SSA plants). SSA plants showed a strong tolerance to oxidative stress caused bythe application of methyl viologen (MV, paraquat), a ROS-generating non-selective herbicide. SSA sweetpotato plants showed higher tolerance to chilling stress than non-transgenic (NT) plants, whereas SSA potato plants showed higher tolerance to high temperature. SSA sweetpotato plants showed a strong tolerance to the application of sulfur dioxide (500 ppb) compared to NT plants. Enhanced tolerance of transgenic crops expressing NDP kinase 2 in cytosols under SWPA2 promoter (SN plants) to environmental stress will be introduced. In addition, the strategies for sustainable agriculture in marginal areas will be discussed