Analysis Of The Expression And The Functions Of Genes Induced By β-Aminobutyric Acid In Tomato(Lycopersicon Esculentum L.) Roots

With the rapid expansion of greenhouse technology, the root-knot Nematode (meloidogyne sp.) has become the major pathogens that threat the qualities and reproductivity of the tomato production. During the past 20 years, B-Aminobutyric Acid (BABA) has been proved to have an effective induced resistance against a broad spectrum of pathogens in agricultural crops and vegetables. Moreover in resistance against root-knot nematode, BABA has been verified one of the most effective abiotic elicitors among salicylic acid, Jasmonic acid and so on. Although the phenomenon has long been known, the underlying mechanisms are poorly understood at the biochemical and molecular level. If the new methods are carried out on the research at the level of gene expression, the concept of the induced resistance by BABA will be more clear and the potential of BABA induced resistance could be better utilized.cDNA amplified fragment length polymorphism analysis (cDNA-AFLP) was used to display transcripts whose expression is rapidly altered during the treatment of soil drench of B-Aminobutyric Acid (BABA) to tomato (Lycopersicon esculentum L) roots. Among 5.000 transcript-derived fragments (TDFs), 23 showed increased abundance and 6 showed decreased abundance. By clone and sequencing, the sequences of 12 TDFs were obtained and 3 of them are all strongly induced and have same length and have the identity of 99%. Reverse transcription-PCR analysis was carried out with these three same TDFs. the result confirm their cDNA-AFLP differential pattern. By RACE, partial 3'cDNA sequence of them was obtain. Then 9 of ESTs and a 3'cDNA sequence were analyzed using methods of bioinformatics.Results of Blast analysis in GenBank showed that the BABA induced resistance involves many processes of plant biochemistry and physiology and are controlled by multi different genes in plant. A high percentage of the differentially regulated TDFs identified in this study has homology to genes commonly regulated during plant defense/stress responses. According to the functions of homology genes, these 10 TDFs could be divided into 5 groups. First group are resistant genes such as pathogenesis-related proteins(PR). BIF13, 14 are members of a PR protein family P69. Second group are transporters, BIF 2, 3, 6. 17, 4 have homologies to genes all responsible for transduction across membrane system of little molecular materials such as H₂O, Ca²+ and anti-fungal agents. Third group is signal transduction proteins, BIF4 was found to have a high homology to Ca²+-binding protein which is an important element in Ca²+ signaling pass way. Forth group is molecular chaperone protein, which help keep activity of certain proteins under stress condition. Fifth groups are those that have no homology to known genes. BIF10, 11, 12.By RACE, we got partial 3'cDNA sequence of BIF17, 962bp. Analysis of Blastn, Blastp and CDD showed that the gene is most probably the gene coding the calcium-transporting ATPase...