| Glucosinolates are nitrogen- and sulfur-containing natural plant secondary metabolites which derived from amino acid, wildly exist in cruciferous plants, such as the model plant Arabidopsis thaliana and lots of important vegetables, like cabbage and broccoli. Glucosinolates are divided into three types: indole glucosinolate, aliphatic glucosinolate and aromatic glucosinolate. The myrosinases which are separated from glucosinolats in natural plant, can hydrolysis glucosinolates into bio-chemical products when damaged by herbivores and insects. The glucosinolates and their hydrolysis products play an important role in defense response to pathogen, herbivores and insects. The glucosinolates are also involved in regulating the biosynthesis of IAA. For human, glucosinolates and their products have cancer-prevent ability. The 8-methylsulfinyloctyl isothiocyanate has the most toxicant to Sclerotinia sclerotiorum within all isothiocyanates derived from aliphatic glucosinolates. Sulforaphane is derived from 4-methylsulphinylbutyl glucosinolate, it has the strongest cancer-combating property in natural plant products. Thus, the research on biosynthesis of glucosinolates has important theoretical and practical significance.The antimicrobial activity of aliphatic glucosinolate and its hydro lysis products is dependent on side chain elongation and modification. The flavin monooxygenases FMO GS-OX play roles in secondary modification of aliphatic glucosinolate, they catalyze the transformation of Methylthioalkyl GSL（MT GSL） to Methylsulfinylalk yl GSL（MS GSL） by S-oxygenation. So far, there have been identified five genes in FMOGS-OXS, as FMOGS-OX1, FMOGS-OX2, FMOGS-OX3, FMOGS-OX4 and FMOGS-OX5. According to the analysis of At1g12130, At1g12160 and At1g12200 compared with other five FMOGS-OX, they have closely genetic relationship. They both have the S-oxygenation ability according to the prediction. They might be involved in the side-chain modification of aliphatic glucosinolate. So, we chose these three genes as the candidate genes of FMOGS-OX. In this paper, we named At1g12130, At1g12160, At1g12200 with FMOGS-OX6, FMOGS-OX7, FMOGS-OX8.To identify the function of FMOGS-OX6, FMOGS-OX7 and FMOGS-OX8, we planed to construct theover-expression lines of these three genes, buy the loss-of-function mutants and research theexpression pattern of these genes. Parts of these work has already been completed by ourlaboratory, including the expression pattern of FMOGS-OX6 and FMOGS-OX7 and the construction ofover-expression lines of FMOGS-OX8. Based on these results, we continued to identify the function of FMOGS-OX6, FMOGS-OX7 and FMOGS-OX8 in this research.The main conclusions of this paper are as follows:（1）Got the over-expression lines of FMOGS-OX6, FMOGS-OX7On the basic of p CAMBIA230035 Su, we inserted the PCR cloning genes of FMOGS-OX6, FMOGS-OX7, got the 35S::FMOGS-OX6 and 35S::FMOGS-OX7 plant expression vectors, shifted the expression vectors into Arabidopsis through agrobacterium, and finally got the over-expression lines of FMOGS-OX6, FMOGS-OX7 after the identification by PCR and RT-PCR.（2）Identified two new FMOGS-OX.According to the alteration of GSL contents in those different gene types plant, MT :（MT+MS）was reduced in seed of 35::FMOGS-OX6, in seed and leaves in 35S::FMOGS-OX7. No significant alteration was observed in their mutant plants, most likely due to other FMOGS-OX made up the function loss. Based on these results, we concluded that FMO GS-OX6、FMOGS-OX7 could catalyze the transformation of MT GSL TO MS GSL, they functioned as FMOGS-OX.The function of FMOGS-OX8 is unapparent, FMOGS-OX8 do not have the ability of S-oxygenation on MT GSL.（3）The expression pattern of FMOGS-OX8.FMOGS-OX8 mainly expressed in the germination stage and blossom stage. It highly expressed in new leaves, main leaf vein, nodes between main roots and sid e roots and nodes between petioles and hypocotyl. |
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