Functional Analysis Of Flavonoids Biosynthesis Mediated By Tomato Transcription Factor SlMYB12, And Functional Analysis Of A Rice Defense-related Gene OsDRxoc5

Two independent aspects were included in this study.Flavonoids, one subclass of plant polyphenols, exhibit a broad spectrum of health-promoting effects, anti-oxidants, anti-virus and so on. Tomato cultivars that are widely planted today only contains a small amount of flavonoids. In this study, by combination with fruit specific promoter E8 and endogenous gene SlMYB12, we got a lot of tomato transgenic lines enriched caffeoyl quinic acid and flavonoids, included lutin, kaempferol rutinoside and naringenin chalcone. The results suggested that tomato endogenous gene SlMYB12 could regulated the flavonoids synthesis as well as the reported AtMYB12 in tomato.Firstly, we constructed the plant expression vector pX6-E8::SlMYB12 by replaced the GFP fragment with DNA fragment of E8 promoter and SlMYB12 in pX6-GFP vector, which cloned from tomato cultivars Micro-Tom and Zhongshu 4, respectively. It was mobilised into Agrobacterium strain AGL1 and introduced into three cherry tomato cultivars, Micro-Tom, Csl09-03 and Shengnvguo via leaf disc method. After identified by PCR, the number of 15, 20 and 31 positive transgenic lines were got with three tomato receptors.The content of flavonoids and caffeoyl quinic acid (CQA) were shown to dramatically increased among the transgenic tomato fruits after analysis by HPLC. In Micro-Tom genetic background, 15.66 and 12.99 mgï¹’g^-1 DW lutin were identified in lines CD07T-2 and CD07T-7. In CSl09-03 genetic background, line CD08T-8 was found a 35.8-time increase in lutin content, and line CD08T^-13 was found to 17.7 times increase of CQA. As to Shengnvguo genetic background, lines CD09-7, CD09^-15, CD09-20 and CD09-33 were identified to 24.4 to 33.6 times increase of lutin. And the content of CQA in CD09-20 and CD09-33 were up to 1.50 and 2.25 mgï¹’g^-1 DW.On this basis, these results were formed a good foundation to support the further study on cultivating safety edible cherry tomato and bioreactor to produce flavonoids products in industry.On the other hand, rice is one of the most important crops in the world. Bacterial streak, caused by Xanthomonas oryzae pv. Oryzicola (Xoc), is one of the most serious diseases of rice worldwide, resulting yield loss of ten to twenty percent for each year. Until now, it is really a big threat to world food production without any effective method to contorl this diease.In this study, we cloned and functional analysis of a Xoc inoculation up-regulated gene OsDRxoc5 which encoded a heat shock protein in susceptible rice variety Mudanjiang 8 and Shengdao 806. In general, we firstly constucted the overexpression (pU1301-OsDRxoc5) and RNAi vecotr (ds1301-OsDRox5) of OsDRxoc5, then introduced into both rice variety Mudanjiang 8 and Shengdao 806. For pU1301-OsDRxoc5, we have achieved for forty-nine and forty-four positive transgenic lines with rice varieties Mudanjiang 8 and Shengdao 806, respectively. And forty-five and thirty positive individuals were achieved for constuct ds1301-OsDRox5 with the two rice varieties.After inoculation with Xoc isolates RS105 at T1 generation, differences in lesion length were visible. Transformants from overexpression vector presented a shorter lesion compared to the control group. And the RNAi ones appeared more serious. In conclusion, OsDRxoc5 was suggested to a positive regulator which involved into the interaction between rice and Xoc isolates RS105. Thus we can use the OsDRox5 for enhancing rice bacterial streak resistance in the future.