The Fine Mapping Of Genes Increasing Fruit Color And Differential Expression Of Genes Related To Fruit Color In Tomato

Fruit color is one of the important quality characters in tomato. Utilizing the genes increasing fruit color from wild germplasm is significant to improving fruit color of cultivated tomatoes. Until now 54 QTLs related to fruit color have been characterized in the world. And QTL-NILs(nearly isogenic lines) or Sub-NILs of major QTLs concerned to fruit color have been developed. TA517, a introgression line containing a 50-cM fragment at the bottom of chromosome 4 of L.hirsutum ace. LA1777 in the background of L.esculenttan cv.E6203, have been demonstrated that it includes 2 QTLs significantly increasing fruit color (denoted IFC QTLs).Based on the previous study, the TA517 and its NILs were employed to fine map the 2 IFC QTLs mentioned as above. Differential expression of the genes at different development stages of fruit was studied through cDNA-AFLP approach. The objectives were to :1) acquire marks tightly linkage to IFC QTLs and enhance the capability manipulating the QTLs for breeders, and provide theory basis for further QTL cloning. 2)study relative genes expression profiling and expression level at different fruit development stages and discus the mechanism that QTLs effect fruit color. The results were as follows:1. The feasibility of analyzing genetic diversity on L.hirsutum by using molecular marks included RFLP and COS (Conserved Ortholog Set) marks located at the linkage map of L.pennellii, and the feasibility of overcoming the shortcomings of RFLP and COS marks with complex manipulating step, time and labor consuming, high cost and radio labeling, were studied. 11 CAPS marks were developed through converting 21 COS and RFLP marks located in a 50 cM DNA fragment from the bottom of chromosome 4 in Lpennellii. The polymorphism is consist as expected by analysis on TA517 and its NILs with these converted 11 marks. The result indicated that RFLP and COS marks can be converted into CAPS marks which can be easily manipulated with high efficiency and low cost.2.AFLP analysis was conducted on L.hirsutum.cv.LAU77, TA517 and E6203 with 72 primer pah's of Ecor I and Mse I. From 60 to 100 bands were amplified with each primer combination. The molecular weight of these bands ranges from 20-600bp. Eight ALFP marks: E32/M47-180, E32/M59-90, E33/M48-160, E37/M49-290, E38/M47-150, E38/M62-300, E41/M59-140 and E41/M60-180 were developed. These eight marks have been located at the fragment of 50-cM at the bottom of chromosome 4 in L.hirsutum tomato by linkage analysis.3.The high-density molecular genetic map, which contains 26 marks, including the newly developed 11 CAPS marks and eight AFLP marks, was constructed. This map covered the 50-cM fragment at the bottom of chromosome 4. The average distance between two marks is 1.92Cm. The map provides a fundamental basis for gene location of qualitative characters, genome comparative study and QTL fine mapping of important agricultural character at this chromosome fragment.4.The fine mapping of two IFC QTLs existing on the 50-cM fragment at the bottom of chromosome 4 in L.hirsutum was conducted. ecol4.1 increase the external color of tomato fruit, icol4.2increase the internal color. ecol4.1 was mapped between mark CT50 and E41/ M59-140 with 2.0cM distance. The distance was decreased 3.5cM by comparison with previous distance 5.5cM. icol4.2 was mapped between mark CP57 and CT173 with 2.3cM distance.5. Utilizing the cDNA-AFLP approach, 162 special TDFs were detected at different development stage of fruit, especially at break stage and red stage. 90 special TDFs that the molecular weight is more than 180bp were reamplified, purified, sequenced and homology analyzed. The result indicated that sequences of 2 TDFs reveal high homology with genes which function was known, TDF-TA1465B-E33/M60-460 (originated from tomato TA1465 at break stage, obtained after selective reamplification with primer E33/M60, its molecular weight is 460bp.) has high homology with Solatium Lycopersiunm chloroplast tRNA-Leu gene; TDF-TA1467B-E33/M60-300 has high homology with Lesculentian putative...