甘露醇-1-磷酸脫氫酶(mtlD基因)是可提高耐鹽性的基因。早期研究已對mtlD基因轉殖發現甘露醇積累對鹽害具緩解作用。楊樹品種廣泛，其具快速生長、造林栽植的園林綠化、生質能的生產和維護全球環境等特點。然而，鹽害影響了這些樹的生存能力，特別是在鹽鹼地區。本研究目的擬利用帶有mtlD基因之農桿腫瘤菌感染歐洲黑楊X毛白楊之雜交種，生產具抗鹽鹼能力的轉殖株。試驗結果顯示，所有轉殖株皆帶有1149 bp之mtlD基因片段。楊樹培殖體發現在含1 mg/L TDZ和0.1 mgL^(-1) NAA之MS培養基，比其它植物生長調節劑的組合，其癒傷組織、不定芽、不定根誘導率較高。較佳農桿菌感染培植體時間為8分鐘，300 ppm的抗生素是抑制農桿菌之較佳濃度。基因轉植株在50、85和120 mM之氯化鈉逆境下，其存活和發根率均明顯高於對照組植物。此外，轉基因楊樹在120 mM之氯化鈉影響下，其生長速度、芽體高度都較對照組好。
Bacterial mannitol-1-phosphate dehydrogenase (mtlD) is known for its tolerance to salinity. Previous work on a number of transgenics having mtlD established the role of mannitol accumulation in alleviating salt stress. Populus species are extensively planted for landscaping, biomass production, and maintenance of the global environment due to their rapid growth and ease of reforestation. However, salt stress tremendously limits these trees’ survivability, particularly within saline areas. The objective of this study was to use Agrobacterium tumefaciens harboring the mtlD gene to infect Populus nigra x P. tomentosa hybrids and produce salt-resistant transgenic plants using a callus organogenesis system. Our results show that all transformants presented an expected fragment of the mtlD transgene of 1149 bp. Significantly higher rates of callus induction, shooting, and rooting in poplar explants were observed in an MS-cultured medium containing 1 mgL^(-1) thidiazuron and 0.1 mgL^(-1) naphthaleneacetic acid compared to other of combinations plant growth regulators. The optimal infection time for A. tumefaciens to infect explants was 8 min, and 300 ppm of cefotaxime was the best concentration for eliminating A. tumefaciens. Survival and rooting rates in transgenic plants under 50, 85, and 120 mM NaCl were both significantly higher than in nontransgenic (NT) plants. In addition, transgenic poplar plants grew faster than NT plants subjected to 120 mM NaCl, as revealed by better growth, longer shoots, and greater plant heights.
