Cloning And Expression Analysisi Of Genes Ralated With Parthenocarpy In Solanum Melongena L.

Eggplant(Solanum melongena L.) was originated from India. In the 4-5 century it was introduced into Eastern Asia. China is the country which has the largest eggplant planting area with more than 50% eggplant planting area in the world. Eggplant parthenocarpic varieties would reduce the flower and fruit drop caused by poor pollination, improved fruit set rate or field yield. The current research on genes which related to parthenocarpy and auxin in eggplant is few. This research drew on the genes related to auxin signal transduction path and parthenocarpy in eggplants, which had great significance for breeding parthenocarpic varieties and study on seedless or few-seed eggplant varieties.The agronomic traits of the parthenocarpic strain D-7-1, D-6 and non-parthenocarpy strain 142 at different flowering stage and fruit stage were measureed. The five genes ARF6, ARF7, ARF8, GH3.6 and IAA9 associated with parthenocarpy in eggplant were obtained through homologous cloning. In order to explore the effect of the five genes on parthenocarpy in Solanum melongena, the expression level at flowering stage and fruit stage was analysised by means of agronomic traits and Real-Time quantitative PCR technology. The main results were as follows:1、The agronomic characters at flowering and fruit stage The results showed that non-parthenocarpic strain 142 belonged to long style type, parthenocarpy strain D-7-1 and D-6 belonged to the short or middle style type. After 10 days of flowering, fruits(ovaries) were in slow growth period. Especially after 7 days of flowering, the weight changed minimally. From 7 days to 10 days after flowering, the fruit weight began to increase. From 10 days to 15 days after flowering, fruit weight increased significantly. And the growth of fruit diameter was also obvious. If removingthe stigma before flowering, the fruit weight of the parthenocarpy line was significantly higher than the unprocessed.2、Five genes associated with parthenocarpy in eggplant had been cloned. According to the conserved sequences genes, homologous primers were designed to amplify five genes named Sm ARF6, Sm ARF7, Sm ARF8, Sm GH3.6 and Sm IAA9 from the c DNA. The gene fragments respectively were 2824 bp, 3234 bp, 2701 bp, 1821 bp and 1017 bp. And their coding sequences encoded 881, 1076, 891, 606 and 304 amino acid residues. Protein domain analysis showed that amino acid sequences encoded by three ARF family genes contained three Pfam domains: the B3 DNA binding domain, auxin response factor and the Aux/IAA family. They belonged to DBD-QSL-rich AD-III-IV type which was an ARF family molecular structure classification; Amino acid sequence deduced by GH3.6 gene contained a Pfam domains named GH3 auxin-responsive promoter; Amino acid sequence deduced by IAA9 gene encoded a Pfam domain named Aux/IAA family. And it had domain I, II, III and IV four conserved domain which belonged to structural characteristics of Aux/IAA family.3. The expression analysis of five genes in three eggplant materials3.1 Expression of three ARF family genes In the parthenocarpic strain D-7-1, ARF6, ARF7 and ARF8 mainly had the higher expression from the 4th day before flowering to the 7th day after flowering while the flower was developing and fruit was setting. It showed that the three genes mainly involved in the process of flower development and fruit setting in D-7-1. From the 7th day to the 20 th day after flowering, the expression of the three genes were all in a low level. It indicated that the three genes could inhibit the rapid growth of fruit; In the non-parthenocarpic strain 142, the three genes were all in the low expression level before flowering. From bloom day to technology ripening their expression was relatively high, especially on the 15 th day after anthesis their expression had a peak. It speculated that the content of hormone in ovary was changed because of pollination, fertilization and seed formation. So the gene expression level increased. The expression level had a peak when the seed was about to appear on the 15 th day after anthesis; In the parthenocarpic strain D-6, the expression level of ARF6 and ARF7 was relatively low in every period, the expression level of ARF8 fluctuated continuously. The result indicated that ARF8 gene played a more important role in the regulation of flower and fruitdevelopment.The expression level of the ARF gene family existed differences in different strains. The parthenocarpic strain had the expression peak around blooming, but the expression level was low at the rapid development period of fruit which was from the 7th day to the 20 th day after flowering. It indicated that the three genes could inhibit the rapid growth of fruit. For the non parthenocarpic strain 142, the gene expression was at a high level. Especially on the 15 th day after anthesis the gene expression all expressed a peak. It indicated that the expression peak in 142 was caused by the content of hormone which was changed because of pollination, fertilization and seed formation.3.2 Expression of GH3.6 and IAA9 The expression level of the GH3.6 was very low from the 10 th day to the 20 th day after anthesis in all strains. The expression was relatively high during the period of anthesis. The D-7-1 had the expression peak on the 2nd day before anthesis and the first day after anthesis; And the parthenocarpic strain D-6 had the expression peak on the 2nd day after anthesis and the 3rd day after anthesis; But for the non-parthenocarpic strain 142, the expression level had small peak on the first day and the 7th day after anthesis. It indicated that the GH3.6 gene reacted mainly at flower development and fruit setting stage but not fruit development stage.In the three materials the expression level of IAA9 was not high. Only in the parthenocarpic strain D-6 the expression level had a small peak on the 7th day after flowering. And on the 15 th day after flowering the non-parthenocarpy strain 142 had a large expression peak. It indicated that the expression peak in 142 was caused by seed formation and IAA9 gene inhibited the process of flower and fruit development.