The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, Ministry of Education, School of Life Science, Shandong University, Shanda Nanlu 27#, Jinan 250100, China.
Plant Cell Environ. 2010 Jun;33(6):877-87. doi: 10.1111/j.1365-3040.2009.02113.x. Epub 2009 Dec 30.
Heavy metal pollution has become one of the most serious environmental problems today. To develop a more efficient plant to clean up heavy metal contaminated soils, a gamma-glutamylcysteine synthetase (GCS) cDNA, named PaGCS, was isolated by PCR from Phragmites australis. The PaGCS sequence was transformed via agroinfection into the heavy metal intolerant grass Agrostis palustris. Five confirmed transgenic A. palustris plants expressing PaGCS were compared with the wild-type line for growth and Cd(2+) accumulation, as well as for the expression of a number of phytochelatin synthesis and stress-responsive enzymes when challenged with Cd(2+) stress. GCS and phytochelatin synthase (PCS) were up-regulated in the transgenic lines. All the transgenic lines accumulated more Cd(2+) and phytochelatins (PCs) than the wild-type line, and three of the five lines grew more effectively than the wild-type after either five or 21 d of Cd(2+) stress. Variation among the transgenics was observed for the distribution of Cd(2+) in the root, shoot and leaf. The malondialdehyde content of all the transgenic lines was lower than that of the wild type under Cd(2+) treatment, while the activity of both superoxide dismutase and peroxidase present in the transgenic lines increased markedly 24 h after Cd(2+) stress, and then rapidly declined.
重金属污染已成为当今最严重的环境问题之一。为了开发更有效的植物来清理重金属污染的土壤，我们通过 PCR 从芦苇中分离出一种γ-谷氨酰半胱氨酸合成酶（GCS）cDNA，命名为 PaGCS。通过根癌农杆菌介导的方法将 PaGCS 序列转化到重金属不敏感的草羊茅中。将 5 个确认的表达 PaGCS 的转基因羊茅植株与野生型进行比较，研究它们在 Cd(2+)胁迫下的生长、Cd(2+)积累以及植物螯合肽合成和应激响应酶的表达情况。结果表明，GCS 和植物螯合肽合成酶（PCS）在转基因株系中上调表达。与野生型相比，所有的转基因株系都积累了更多的 Cd(2+)和植物螯合肽（PCs），在 5 或 21 d 的 Cd(2+)胁迫后，其中 3 个株系的生长情况优于野生型。在 Cd(2+)处理下，所有转基因株系的丙二醛含量均低于野生型，而超氧化物歧化酶和过氧化物酶的活性在 Cd(2+)胁迫 24 h 后明显增加，然后迅速下降。
