| Peanut is one of the five major oil crops in world.It is also an important oil and economic crop ranked the first in yield per hecter,total output and export amount for cash of all the oil crops in China.It is a gernocarpic crop with the characteristes of flowering above the ground but podding under the ground,and with pods as the main harvested organ.Thd pod growth and development status of peanut affect much on the yield and quality formation,which is also regulated by genes expression and regulation in pod developing.Mining and studing genes involved in the pod development is of great importance to future pod yield and quality improvement.In the study we first conducted a large-scale sequencing for a full-length cDNA library constructed with pods of various developing stages,then focused on investigating obtained sequences using bioinformatics method to analyze and forecast their structure characteristics and function.Many genes relevant to seed development,quality formation,and resistance were got, which should have benefits to the subsequent in-depth study.The main results are as follows.1.2000 clones from the cDNA library were made one read at their 5' terminal,and 1827 ESTs were got.Preliminary analysis and feature notes were made for the ESTs.It was found that 80 percent of ESTs obtained are similar to known functional genes,and.another 366 ESTs are unknown genes..Among the 1827 ESTs,770 ESTs were identified as Unigene,which have been released on GenBank(accession numbers:ES490643-491295 and EY396003-396119).Many of the abtained genes was the first report in peanut.One hundred genes with more important function were subjected to two-way sequencing and 51 full-length genes were acquired after preliminary analysis.2.The 1827 ESTs were classified according to their function,then 408different genes were found,and 74 genes have at least two copies of same function,or homologs,or identity sequences, which made up to 1220 ESTs,accounting for 66.7%of all.Some storage proteins genes had highly degree of homologic copies.These functional genes could be clustered into 7 categories of seed storage protein,energy metabolism,transport,protein synthesis and degradation,protein modification,signal transduction,resistance-related proteins.Based on analyzing metabolic pathway,12 genes were found involved in fatty acid metabolism,10 genes involved in energy metabolism,40 genes involved in plant disease resistant genes and 22 genes participating in stress-related resistance3.After removed the redundancy sequences from 1827 ESTs,SSRs sequences were mined with SSRIT search software,and 19 different SSR sequences were found.Primer pairs were designed for the 19 EST-SSR(cSSR).These SSRs could be used as molecule marker in traits mapping and genetic map construction.4.A Glycine canescens seed maturation protein LEA 4-like gene and a Glycine max Ca+2-binding EF hand protein GmPM13-related gene selected from the full length genes were evaluated for their structure and function prediction by bioinformatic method.The two full-length gene were 750 bps and 1250 bps in length,respectively,with coding regions of 515bps and 678 bps,encoding two proteins of 172 a.a.and 225 a.a,in the order.LEA4-like protein is a drought protection protein which can be used to improve drought resistance by gene engineering. GmPM14-related protein is a acidic calcium-binding protein,hydrophobic strong,containing abumdant ofα-helix,a lot of extended strands and large number of random coils,which may demonstrates a broad physiological functions.The above findings preliminarily revealed the composition and function of expression genes in developing seed.A number of valuable genes were than found,especially for the two individual genes with structural and functional prediction made in detail.This provides a basis for further molecular biology and genetic engineering studies in peanut. |
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