The AVA gene with and without intron were inserted downstream of 35S promoter into a vetor pBI121 to get pBI121AVA-GUS and pBI121AVAc-GUS vetor respectively.
By the PCR method, we got a fragment about 1200 bp, sequencing and homoly analysis result showed that the fragment was 1192 bp's long, and was 94.1%, 82.4% and 75.2% homoly to the cDNA sequence of apricot, pear and apple respectively, it also showed the sequence might have a intron.
Comparison of the PGIP DNA and cDNA sequence showed that the PGIP DNA seqence have two extrons interrupted by a 147 bp's intron, the first extron indued 581 base pair, the second is 464 bp.
The results from insect bioassay with peach aphid(Myzus persicae) showed that the transgenic plants of pBI121AVA-GUS and pBI121AVAc-GUS were aphid resistant,evidenced by a 60.81%~50.63% reduction in insect population density,some plants were more than 97%.
A pair of primers, designed from conserved regions of plant soluble acid invertase gene, was used to amplify 1096bp fragment by polymerase chain reaction (PCR). The fragment was cloned into pUCm-T, and then sequenced.
The result of sequence analysis indicated that the length of cDNA and DNA fragments of Lectin gene and the length of cDNA and DNA fragments of Pectate Lyase gene were 508 bp,575 bp,1,316 bp and 1,858 bp respectively.
A pair of primers was designed according to the conserved sequences of plant so luble acid invertase genes, and a 743bp fragment was amplified by polymerase cha in reaction (PCR) using the genomic DNA of Malus pumila (Liao Fu) as a templa te.
Furthermore, characteristics of EID, such as intron phase, distribution of different splice sites, and the relationship between genome size and intron proportion or intron density, have been studied.
The exon-intron structure of these genes has been analyzed in zebrafish Danio rerio, loach Misgurnus fossilis, fugu Takifugu rubripes, and Nile puffer Tetraodon fahaka.
This is supported by high sequence similarity between mlc1 and mlc3 as well as by the exon-intron structure of these genes and their localization on different chromosomes.