Transfer of the yeast salt tolerance gene HAL1 to Cucumis melo L. cultivars and in vitro evaluation of salt tolerance.
An Agrobacterium-mediated gene transfer method for production of transgenic melon plants has been optimized. The HAL1 gene, an halotolerance gene isolated from yeast, was inserted in a chimaeric construct and joined to two marker genes: a selectable-neomycin phosphotransferase-II (nptII)-, and a reporter-beta-glucuronidase (gus)-. The entire construct was introduced into commercial cultivars of melon. Transformants were selected for their ability to grow on media containing kanamycin. Transformation was confirmed by GUS assays, PCR analysis and Southern hybridization. Transformation efficiency depended on the cultivar, selection scheme used and the induction of vir-genes by the addition of acetosyringone during the cocultivation period. The highest transformation frequency, 3% of the total number of explants cocultivated, was obtained with cotyledonary explants of cv. 'Pharo'. Although at a lower frequency (1.3%), we have also succeeded in the transformation of leaf explants. A loss of genetic material was detected in some plants, and results are in accordance with the directional model of T-DNA transfer. In vitro cultured shoots from transgenic populations carrying the HAL1 gene were evaluated for salt tolerance on shoot growth medium containing 10 gl-1 NaCl. Although root and vegetative growth were reduced, transgenic HAL1-positive plants consistently showed a higher level of tolerance than control HAL1-negative plants.
Bordas
M
M
Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-C.S.I.C., Spain.
Montesinos
C
C
Dabauza
M
M
Salvador
A
A
Roig
L A
LA
Serrano
R
R
Moreno
V
V
D000098:Acetophenones / Q000494:pharmacology; D015152:Blotting, Northern; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018920:Coculture Techniques; D046508:Culture Techniques; D004247:DNA / Q000032:analysis; D005656:Fungal Proteins; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D005966:Glucuronidase / Q000235:genetics* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D019868:Kanamycin Kinase; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics*; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D012231:Rhizobium / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts / Q000378:metabolism; D014170:Transformation, Genetic; D019076:Transgenes; D015003:Yeasts / Q000235:genetics*
D000098:Acetophenones; D005656:Fungal Proteins; C076232:HAL1 protein, S cerevisiae; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D012492:Salts; C051667:acetosyringone; D004247:DNA; D017853:Phosphotransferases (Alcohol Group Acceptor); D019868:Kanamycin Kinase; D005966:Glucuronidase