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OsSOS1 <strong>and</strong> ZxSOS1. These results suggest that NsNHX1
encodes a <strong>to</strong>noplast Na + /H + antiporter, which belongs <strong>to</strong>
<strong>the</strong> cation‐pro<strong>to</strong>n antiporter family.
Transient expression of an NsNHX1::GFP translational
fusion product in onion epidermal cells is visualized by
epifluorescence microscopy. GFP fluorescence is
concentrated <strong>to</strong> <strong>the</strong> vacuolar membrane. The result
indicates that <strong>the</strong> NsNHX1 is located in <strong>to</strong>noplast of plant
cells.Semi‐quantitative RT‐PCR analysis shows that <strong>the</strong>
mRNA level of NsNHX1 is significantly higher in leaf than
those in stem or root. The steady‐state level of NsNHX1
transcript is up‐regulated by treatment with NaCl, cold or
ABA, but not induced by drought. In <strong>the</strong> different salt
degree stress, <strong>the</strong> NsNHX1 transcript level has <strong>the</strong>
maximum value in treatment with 200 mM NaCl.
To analyze <strong>the</strong> function <strong>and</strong> expression of NsNHX1, 2
transgenic lines of Arabidopsis WT <strong>and</strong> nhx1 mutation
with heterologously expressed of NsNHX1 were made.
The T2 generations homozygous plants will be used <strong>to</strong>
analyze <strong>the</strong> function of NsNHX1 exposed <strong>to</strong> salt stress.
The Nitraria is a genus of flowering plants in
Zygophyllaceae family, which grows primarily in deserts
<strong>and</strong> semideserts, <strong>and</strong> exhibits a strong salt resistance.
Therefore, <strong>the</strong> research on molecular mechanism of salt
<strong>to</strong>lerance is very necessary in Nitraria.
Characterizing polysaccharide biosyn<strong>the</strong>sis
in plant for syn<strong>the</strong>sis de novo <strong>and</strong> molecular
design
Baocai ZHANG
Institute of Genetics <strong>and</strong> Developmental Biology, Beijing 100101,
China. Email: bczhang@genetics.ac.cn
Polysaccharides, <strong>the</strong> most abundant organic polymers in
<strong>the</strong> world, have versatile applications. Besides being a
basic structural element, enabling plants <strong>to</strong> st<strong>and</strong> up, plant
cells wall also contain polysaccharides with regulation
function <strong>and</strong> clinical effects. Although progress has been
made on identifying glycosyltransferases involved in each
main polysaccharide syn<strong>the</strong>sis, not enough proteins
responsible for syn<strong>the</strong>sis have been identified <strong>to</strong> offer <strong>the</strong>
panoramic view. In a model plant rice, we identified
several genes required for wall syn<strong>the</strong>sis by genetic
analysis, covering glycosyltransferases, nucleotide sugar
transporters <strong>and</strong> proteins for vesicle trafficking <strong>and</strong>
extracellular deposition. How <strong>the</strong> polysaccharides were
efficiently syn<strong>the</strong>sized <strong>and</strong> assembly will be our next
focus. We have already started <strong>to</strong> reconstruct syn<strong>the</strong>sis
machinery in Pichia now. This progress will pave <strong>the</strong> way
for heterologous syn<strong>the</strong>sis de novo <strong>and</strong> molecular design
of high‐value polysaccharides.
Cloning <strong>and</strong> characterization of c<strong>and</strong>idate
genes from an ALS inhabiting
herbicide­resistant mutant line M9 in
brassica napus
Maolong HU, Huiming PU, Jian Qin GAO, Wei
Hua LONG, Cun Kou QI, Jiefu ZHANG <strong>and</strong> Song
CHEN
Institute of industrial Crops, Jiangsu Academy of Agricultural
Sciences, Nanjing Sub‐center, National Center of Oil Crops
Improvement <strong>and</strong> Key Labora<strong>to</strong>ry of Cot<strong>to</strong>n <strong>and</strong> Rapeseed
(Nanjing), Ministry of Agriculture, Nanjing 210014, China.
The application of herbicide‐resistant rapeseed has many
advantages such as saving labor cost, increasing benefits
<strong>and</strong> promoting soil <strong>and</strong> water conservation. However, due
<strong>to</strong> <strong>the</strong> lack of herbicide‐resistant genes with independent
intellectual property rights, commercialized
herbicide‐resistant rapeseed has not yet been planted in
China. A mutant line M9 conferring resistance <strong>to</strong> <strong>the</strong>
ace<strong>to</strong>lactate synthase (ALS) or ace<strong>to</strong>hydroxyacid synthase
(AHAS) inhibiting herbicides was previously found in <strong>the</strong>
rapeseed (Brassica napus L.) by spontaneous mutation.
The resistance of M9 was inherited as a single, dominant
nuclear gene on <strong>the</strong> basis of genetic analyses. Three
genes BnALS1‐3 encoding ALS were isolated from <strong>the</strong>
mutant <strong>and</strong> wild type, using <strong>the</strong> homology‐based
c<strong>and</strong>idate gene method. Molecular analysis identified a
single‐point mutation leading <strong>to</strong> an amino acid
substitution from serine 653 (relative <strong>to</strong> <strong>the</strong> Arabidopsis
thaliana ALS sequence) (AGC) <strong>to</strong> asparagine (AAC) at <strong>the</strong>
herbicide‐binding site of <strong>the</strong> rapeseed BnALS1 gene. The
resistant gene of M9 was designed BnALS1R <strong>and</strong>
transformed <strong>to</strong> MICMS (Mutsu‐Isuzu Cy<strong>to</strong>plasmic Male
Sterile) res<strong>to</strong>rer lines by hybridization <strong>and</strong> microspore
culture. All <strong>the</strong> resistant res<strong>to</strong>re lines had <strong>the</strong> specific
b<strong>and</strong> of BnALS1R by PCR analysis <strong>and</strong> sequencing, which
definitely confirmed that <strong>the</strong> resistance of M9 resulted
from <strong>the</strong> point mutation (Ser653Asn). These results
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