Agrobacterium-mediated transformation with a gene encoding for betaine-aldehyde dehydrogenase(BADH) in brassica napus
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DOI:10.7606/j.issn.1000-7601.2007.04.02
Key Words: Brassica napus  transformation  BADH  tolerance to salt
Author NameAffiliation
HAN De-jun College of Agronomy, Northwest A & F University, Yangling, Shaanxi 712100, China 
CHEN Yao-feng College of Agronomy, Northwest A & F University, Yangling, Shaanxi 712100, China 
LI Chun-lian College of Agronomy, Northwest A & F University, Yangling, Shaanxi 712100, China 
GUO Dong-wei College of Agronomy, Northwest A & F University, Yangling, Shaanxi 712100, China 
LI Zheng-qi College of Plant Protect, Northwest A & F University, Yangling, Shaanxi 712100, China 
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Abstract:
      Glycinebetaine(GB) is one of the organic compatible solutes that can accumulate rapidly in many plants under salinity or drought stress. Betaine aldehyde dehydrogenase(BADH) is the enzyme that catalyzes the second step in the synthesis of the GB. Cotyledon and hypocotyl explants of 9 varieties of B. napus were used to investigate the regeneration competence of them under the stress of Agrobacterium, and establish an efficient transformation experiments for the BADH gene. The result indicated that the 9 varieties could be divided into three types according to the response to the infection of Agrobacterium: resistant type(R); supper susceptive type(SS) and middle type(M). The R type could not form regeneration shoot owing to hypersusceptibility response at the cut of the explant; the SS type could not also form regeneration shoot owing to propagate so far on the surfer of the explant; and only the M type could form regeneration shoot. The frequency of regeneration shoot can be enhanced by optimizing the co-cultivate condition: using filter paper as co-cultivate support, it results in not only avoiding vitrification of explant, but also prolong the time of co-cultivate, thus the cells on the explant could have enough time to regenerate. The use of AgNO3 (3~6 mg/L) was a prerequisite for efficient shoot regeneration under selective conditions, but the mount is dependented on genotype. The hypocotyl explant was more easy death infected by Agrobacterium than cotyledon explant. two Brassica napus lines of breeding, P137 and 487, using Agrobacterium tumefaciens strain AGL1 carrying a binary vector pBin438, with cotyledon and hypocotyl regeneration system. Polymerase chain reaction analyses demonstrated that the BADH gene had integrated into the genome of B. napus. Transgenic B. napus plants showed the levels of activity of BADH were similar to or higher than wild-type plants leaves after exposure to salt stress. Observations on rooting development under the salt stress with concentrations up to 0.5% suggested that the transgenic plants exhibited tolerance to salt stress than wild-type plants.