| Pollen tubes play an important role in the whole process of plants’ pollination and fertilization, they act as the carrier of sperm cells, and their growth is almost the most important stage in the sexual reproduction of angiosperms. The reproduction process between diploid (B2) and natural triploid mutant (B355) of ’Longquan No.1’ loquat is quite different, there are some abnormal activities during the process of the meiosis and pollination and fertilization of B355, the germination and elongation of pollen tubes are blocked. These are similar phenomena in most of polyploidy plants. So the research on the regular mechanic of pollen tubes growth and development plays an important act on the reproduction researches of triploid loquat, this also can refer to the similar research of some other polyploidy plants. There are several genes that regulate the development of pollen tubes, and the blocks of triploid loquat pollen tubes development is mostly related to the difference of gene expression as compared to the diploid. So the research on the genes and its expression can promote the related researches of triploid pollen tubes development.This research is based on the transcriptome sequencing and digital gene expression profile of B2 and B355 loquat, partial sequences of 5 genes related to the pollen tube growth have been cloned, the bioinformation tools and real-time PCR were used to analyze the expression and biological characters of these genes in the same time. The difference of expression characters and profiles of these genes between diploid and triploid loquat were be certified. All these provided some important reference values on the critical gene screening and mechanism of its regulating network and some other related researches. The main results of this research showed as the following:1. Screening of the different expression genes related the pollen tube growth of B2 and B355.18 of 2413 different expressed genes that related to the pollen tube growth were screened out from the transcriptome sequencing and digital gene expression profiles, CL1893, CL13463, CL12486, CL9564 and Unigene4683 were the candidate genes whose expressions were quite different between B2 and B355. 2. Partial sequences cloning of CL1893, CL13463, CL12486, CL9564 and Unigene4683 genes.① CL1893 fragment with the length of 1034bp is a homologous gene of the leucine-rich repeats receptor-like protein kinase (LRR-RLK), it may located on the top of pollen tubes, and participated in the process of its growth. ② The fragments of 426 bp length CL13463 and 736 bp length CL9564 maybe the homologous gene of ANX1 and ANX2 respectively, they probably take functions to maintain the form of pollen tubes.③ 972 bp length CL12486 fragment is the homologous gene of Rho GEF, and it may participated in the growth progress of pollen tubes.④ 740bp length Unigene4683 fragment is the homologous gene of pectinesterase, it may be take part in the regulation the growth speed of pollen tubes. All these five gene fragments were predicted to be related to the pollen tube growth.3. Analysis on the gene expression characters of cloned genes.These five cloned gene fragments all may be taken function during the growth process of pollen tubes, and all expressed in the used B2 and B355, but there had some different expression profiles between them. ① These genes were up regulated in B2 and down regulated in B355. ② The ploidy of pollen provider may influence the expression profile of genes. ③The ploidy of female gamete provider may influence the expression time and degree. |
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